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java.lang.Objectorg.apache.commons.lang3.StringUtils
public class StringUtils
Operations on String that are
null safe.
The StringUtils class defines certain words related to
String handling.
null"")' ', char 32)Character.isWhitespace(char)String.trim()StringUtils handles null input Strings quietly.
That is to say that a null input will return null.
Where a boolean or int is being returned
details vary by method.
A side effect of the null handling is that a
NullPointerException should be considered a bug in
StringUtils.
Methods in this class give sample code to explain their operation.
The symbol * is used to indicate any input including null.
#ThreadSafe#
String| Field Summary | |
|---|---|
static String |
EMPTY
The empty String "". |
static int |
INDEX_NOT_FOUND
Represents a failed index search. |
| Constructor Summary | |
|---|---|
StringUtils()
StringUtils instances should NOT be constructed in
standard programming. |
|
| Method Summary | ||
|---|---|---|
static String |
abbreviate(String str,
int maxWidth)
Abbreviates a String using ellipses. |
|
static String |
abbreviate(String str,
int offset,
int maxWidth)
Abbreviates a String using ellipses. |
|
static String |
abbreviateMiddle(String str,
String middle,
int length)
Abbreviates a String to the length passed, replacing the middle characters with the supplied replacement String. |
|
static String |
capitalize(CharSequence cs)
Capitalizes a String changing the first letter to title case as per Character.toTitleCase(char). |
|
static String |
center(String str,
int size)
Centers a String in a larger String of size size
using the space character (' '). |
|
static String |
center(String str,
int size,
char padChar)
Centers a String in a larger String of size size. |
|
static String |
center(String str,
int size,
String padStr)
Centers a String in a larger String of size size. |
|
static String |
chomp(String str)
Removes one newline from end of a String if it's there, otherwise leave it alone. |
|
static String |
chomp(String str,
String separator)
Removes separator from the end of
str if it's there, otherwise leave it alone. |
|
static String |
chop(String str)
Remove the last character from a String. |
|
static String |
concat(Object... elements)
Joins the provided elements into a single String. |
|
static String |
concatWith(String separator,
Object... elements)
Joins the provided elements into a single String, with the specified separator between each element. |
|
static boolean |
contains(String str,
int searchChar)
Checks if String contains a search character, handling null. |
|
static boolean |
contains(String str,
String searchStr)
Checks if String contains a search String, handling null. |
|
static boolean |
containsAny(String cs,
char[] searchChars)
Checks if the CharSequence contains any character in the given set of characters. |
|
static boolean |
containsAny(String cs,
String searchChars)
Checks if the CharSequence contains any character in the given set of characters. |
|
static boolean |
containsIgnoreCase(String str,
String searchStr)
Checks if String contains a search String irrespective of case, handling null. |
|
static boolean |
containsNone(CharSequence cs,
char[] searchChars)
Checks that the CharSequence does not contain certain characters. |
|
static boolean |
containsNone(CharSequence cs,
String invalidChars)
Checks that the CharSequence does not contain certain characters. |
|
static boolean |
containsOnly(CharSequence cs,
char[] valid)
Checks if the CharSequence contains only certain characters. |
|
static boolean |
containsOnly(CharSequence cs,
String validChars)
Checks if the CharSequence contains only certain characters. |
|
static boolean |
containsWhitespace(String str)
Check whether the given String contains any whitespace characters. |
|
static int |
countMatches(String str,
String sub)
Counts how many times the substring appears in the larger String. |
|
static
|
defaultIfEmpty(T str,
T defaultStr)
Returns either the passed in CharSequence, or if the CharSequence is empty or null, the value of defaultStr. |
|
static String |
defaultString(String str)
Returns either the passed in String, or if the String is null, an empty String (""). |
|
static String |
defaultString(String str,
String defaultStr)
Returns either the passed in String, or if the String is null, the value of defaultStr. |
|
static String |
deleteWhitespace(String str)
Deletes all whitespaces from a String as defined by Character.isWhitespace(char). |
|
static String |
difference(String str1,
String str2)
Compares two Strings, and returns the portion where they differ. |
|
static boolean |
endsWith(String str,
String suffix)
Check if a String ends with a specified suffix. |
|
static boolean |
endsWithIgnoreCase(String str,
String suffix)
Case insensitive check if a String ends with a specified suffix. |
|
static boolean |
equals(CharSequence cs1,
CharSequence cs2)
Compares two CharSequences, returning true if they are equal. |
|
static boolean |
equalsIgnoreCase(String str1,
String str2)
Compares two Strings, returning true if they are equal ignoring
the case. |
|
static String |
getCommonPrefix(String... strs)
Compares all Strings in an array and returns the initial sequence of characters that is common to all of them. |
|
static int |
getLevenshteinDistance(CharSequence s,
CharSequence t)
Find the Levenshtein distance between two Strings. |
|
static int |
indexOf(String str,
int searchChar)
Finds the first index within a String, handling null. |
|
static int |
indexOf(String str,
int searchChar,
int startPos)
Finds the first index within a String from a start position, handling null. |
|
static int |
indexOf(String str,
String searchStr)
Finds the first index within a String, handling null. |
|
static int |
indexOf(String str,
String searchStr,
int startPos)
Finds the first index within a String, handling null. |
|
static int |
indexOfAny(CharSequence cs,
char[] searchChars)
Search a CharSequence to find the first index of any character in the given set of characters. |
|
static int |
indexOfAny(CharSequence cs,
String searchChars)
Search a CharSequence to find the first index of any character in the given set of characters. |
|
static int |
indexOfAny(String str,
String[] searchStrs)
Find the first index of any of a set of potential substrings. |
|
static int |
indexOfAnyBut(CharSequence cs,
char[] searchChars)
Searches a CharSequence to find the first index of any character not in the given set of characters. |
|
static int |
indexOfAnyBut(String str,
String searchChars)
Search a String to find the first index of any character not in the given set of characters. |
|
static int |
indexOfDifference(CharSequence... css)
Compares all CharSequences in an array and returns the index at which the CharSequences begin to differ. |
|
static int |
indexOfDifference(CharSequence cs1,
CharSequence cs2)
Compares two CharSequences, and returns the index at which the CharSequences begin to differ. |
|
static int |
indexOfIgnoreCase(String str,
String searchStr)
Case in-sensitive find of the first index within a String. |
|
static int |
indexOfIgnoreCase(String str,
String searchStr,
int startPos)
Case in-sensitive find of the first index within a String from the specified position. |
|
static boolean |
isAllLowerCase(CharSequence cs)
Checks if the CharSequence contains only lowercase characters. |
|
static boolean |
isAllUpperCase(CharSequence cs)
Checks if the CharSequence contains only uppercase characters. |
|
static boolean |
isAlpha(CharSequence cs)
Checks if the CharSequence contains only unicode letters. |
|
static boolean |
isAlphanumeric(CharSequence cs)
Checks if the CharSequence contains only unicode letters or digits. |
|
static boolean |
isAlphanumericSpace(CharSequence cs)
Checks if the CharSequence contains only unicode letters, digits or space ( ' '). |
|
static boolean |
isAlphaSpace(CharSequence cs)
Checks if the CharSequence contains only unicode letters and space (' '). |
|
static boolean |
isAsciiPrintable(CharSequence cs)
Checks if the CharSequence contains only ASCII printable characters. |
|
static boolean |
isBlank(CharSequence cs)
Checks if a CharSequence is whitespace, empty ("") or null. |
|
static boolean |
isEmpty(CharSequence cs)
Checks if a CharSequence is empty ("") or null. |
|
static boolean |
isNotBlank(CharSequence cs)
Checks if a CharSequence is not empty (""), not null and not whitespace only. |
|
static boolean |
isNotEmpty(CharSequence cs)
Checks if a CharSequence is not empty ("") and not null. |
|
static boolean |
isNumeric(CharSequence cs)
Checks if the CharSequence contains only unicode digits. |
|
static boolean |
isNumericSpace(CharSequence cs)
Checks if the CharSequence contains only unicode digits or space ( ' '). |
|
static boolean |
isWhitespace(CharSequence cs)
Checks if the CharSequence contains only whitespace. |
|
static String |
join(Iterable<?> iterable,
char separator)
Joins the elements of the provided Iterable into
a single String containing the provided elements. |
|
static String |
join(Iterable<?> iterable,
String separator)
Joins the elements of the provided Iterable into
a single String containing the provided elements. |
|
static String |
join(Iterator<?> iterator,
char separator)
Joins the elements of the provided Iterator into
a single String containing the provided elements. |
|
static String |
join(Iterator<?> iterator,
String separator)
Joins the elements of the provided Iterator into
a single String containing the provided elements. |
|
static String |
join(Object[] array)
Joins the elements of the provided array into a single String containing the provided list of elements. |
|
static String |
join(Object[] array,
char separator)
Joins the elements of the provided array into a single String containing the provided list of elements. |
|
static String |
join(Object[] array,
char separator,
int startIndex,
int endIndex)
Joins the elements of the provided array into a single String containing the provided list of elements. |
|
static String |
join(Object[] array,
String separator)
Joins the elements of the provided array into a single String containing the provided list of elements. |
|
static String |
join(Object[] array,
String separator,
int startIndex,
int endIndex)
Joins the elements of the provided array into a single String containing the provided list of elements. |
|
static int |
lastIndexOf(String str,
int searchChar)
Finds the last index within a String, handling null. |
|
static int |
lastIndexOf(String str,
int searchChar,
int startPos)
Finds the last index within a String from a start position, handling null. |
|
static int |
lastIndexOf(String str,
String searchStr)
Finds the last index within a String, handling null. |
|
static int |
lastIndexOf(String str,
String searchStr,
int startPos)
Finds the first index within a String, handling null. |
|
static int |
lastIndexOfAny(String str,
String[] searchStrs)
Find the latest index of any of a set of potential substrings. |
|
static int |
lastIndexOfIgnoreCase(String str,
String searchStr)
Case in-sensitive find of the last index within a String. |
|
static int |
lastIndexOfIgnoreCase(String str,
String searchStr,
int startPos)
Case in-sensitive find of the last index within a String from the specified position. |
|
static int |
lastOrdinalIndexOf(String str,
String searchStr,
int ordinal)
Finds the n-th last index within a String, handling null. |
|
static String |
left(String str,
int len)
Gets the leftmost len characters of a String. |
|
static String |
leftPad(String str,
int size)
Left pad a String with spaces (' '). |
|
static String |
leftPad(String str,
int size,
char padChar)
Left pad a String with a specified character. |
|
static String |
leftPad(String str,
int size,
String padStr)
Left pad a String with a specified String. |
|
static int |
length(CharSequence cs)
Deprecated. See CharSequenceUtils.length(CharSequence) |
|
static String |
lowerCase(String str)
Converts a String to lower case as per String.toLowerCase(). |
|
static String |
lowerCase(String str,
Locale locale)
Converts a String to lower case as per String.toLowerCase(Locale). |
|
static String |
mid(String str,
int pos,
int len)
Gets len characters from the middle of a String. |
|
static int |
ordinalIndexOf(String str,
String searchStr,
int ordinal)
Finds the n-th index within a String, handling null. |
|
static String |
overlay(String str,
String overlay,
int start,
int end)
Overlays part of a String with another String. |
|
static String |
remove(String str,
char remove)
Removes all occurrences of a character from within the source string. |
|
static String |
remove(String str,
String remove)
Removes all occurrences of a substring from within the source string. |
|
static String |
removeEnd(String str,
String remove)
Removes a substring only if it is at the end of a source string, otherwise returns the source string. |
|
static String |
removeEndIgnoreCase(String str,
String remove)
Case insensitive removal of a substring if it is at the end of a source string, otherwise returns the source string. |
|
static String |
removeStart(String str,
String remove)
Removes a substring only if it is at the begining of a source string, otherwise returns the source string. |
|
static String |
removeStartIgnoreCase(String str,
String remove)
Case insensitive removal of a substring if it is at the begining of a source string, otherwise returns the source string. |
|
static String |
repeat(String str,
int repeat)
Repeat a String repeat times to form a
new String. |
|
static String |
repeat(String str,
String separator,
int repeat)
Repeat a String repeat times to form a
new String, with a String separator injected each time. |
|
static String |
replace(String text,
String searchString,
String replacement)
Replaces all occurrences of a String within another String. |
|
static String |
replace(String text,
String searchString,
String replacement,
int max)
Replaces a String with another String inside a larger String, for the first max values of the search String. |
|
static String |
replaceChars(String str,
char searchChar,
char replaceChar)
Replaces all occurrences of a character in a String with another. |
|
static String |
replaceChars(String str,
String searchChars,
String replaceChars)
Replaces multiple characters in a String in one go. |
|
static String |
replaceEach(String text,
String[] searchList,
String[] replacementList)
Replaces all occurrences of Strings within another String. |
|
static String |
replaceEachRepeatedly(String text,
String[] searchList,
String[] replacementList)
Replaces all occurrences of Strings within another String. |
|
static String |
replaceOnce(String text,
String searchString,
String replacement)
Replaces a String with another String inside a larger String, once. |
|
static String |
reverse(String str)
Reverses a String as per StringBuilder.reverse(). |
|
static String |
reverseDelimited(String str,
char separatorChar)
Reverses a String that is delimited by a specific character. |
|
static String |
right(String str,
int len)
Gets the rightmost len characters of a String. |
|
static String |
rightPad(String str,
int size)
Right pad a String with spaces (' '). |
|
static String |
rightPad(String str,
int size,
char padChar)
Right pad a String with a specified character. |
|
static String |
rightPad(String str,
int size,
String padStr)
Right pad a String with a specified String. |
|
static String[] |
split(String str)
Splits the provided text into an array, using whitespace as the separator. |
|
static String[] |
split(String str,
char separatorChar)
Splits the provided text into an array, separator specified. |
|
static String[] |
split(String str,
String separatorChars)
Splits the provided text into an array, separators specified. |
|
static String[] |
split(String str,
String separatorChars,
int max)
Splits the provided text into an array with a maximum length, separators specified. |
|
static String[] |
splitByCharacterType(String str)
Splits a String by Character type as returned by java.lang.Character.getType(char). |
|
static String[] |
splitByCharacterTypeCamelCase(String str)
Splits a String by Character type as returned by java.lang.Character.getType(char). |
|
static String[] |
splitByWholeSeparator(String str,
String separator)
Splits the provided text into an array, separator string specified. |
|
static String[] |
splitByWholeSeparator(String str,
String separator,
int max)
Splits the provided text into an array, separator string specified. |
|
static String[] |
splitByWholeSeparatorPreserveAllTokens(String str,
String separator)
Splits the provided text into an array, separator string specified. |
|
static String[] |
splitByWholeSeparatorPreserveAllTokens(String str,
String separator,
int max)
Splits the provided text into an array, separator string specified. |
|
static String[] |
splitPreserveAllTokens(String str)
Splits the provided text into an array, using whitespace as the separator, preserving all tokens, including empty tokens created by adjacent separators. |
|
static String[] |
splitPreserveAllTokens(String str,
char separatorChar)
Splits the provided text into an array, separator specified, preserving all tokens, including empty tokens created by adjacent separators. |
|
static String[] |
splitPreserveAllTokens(String str,
String separatorChars)
Splits the provided text into an array, separators specified, preserving all tokens, including empty tokens created by adjacent separators. |
|
static String[] |
splitPreserveAllTokens(String str,
String separatorChars,
int max)
Splits the provided text into an array with a maximum length, separators specified, preserving all tokens, including empty tokens created by adjacent separators. |
|
static boolean |
startsWith(String str,
String prefix)
Check if a String starts with a specified prefix. |
|
static boolean |
startsWithAny(String string,
String... searchStrings)
Check if a String starts with any of an array of specified strings. |
|
static boolean |
startsWithIgnoreCase(String str,
String prefix)
Case insensitive check if a String starts with a specified prefix. |
|
static String |
strip(String str)
Strips whitespace from the start and end of a String. |
|
static String |
strip(String str,
String stripChars)
Strips any of a set of characters from the start and end of a String. |
|
static String |
stripAccents(String input)
Removes the accents from a string. |
|
static String[] |
stripAll(String[] strs)
Strips whitespace from the start and end of every String in an array. |
|
static String[] |
stripAll(String[] strs,
String stripChars)
Strips any of a set of characters from the start and end of every String in an array. |
|
static String |
stripEnd(String str,
String stripChars)
Strips any of a set of characters from the end of a String. |
|
static String |
stripStart(String str,
String stripChars)
Strips any of a set of characters from the start of a String. |
|
static String |
stripToEmpty(String str)
Strips whitespace from the start and end of a String returning an empty String if null input. |
|
static String |
stripToNull(String str)
Strips whitespace from the start and end of a String returning null if the String is empty ("") after the strip. |
|
static String |
substring(String str,
int start)
Gets a substring from the specified String avoiding exceptions. |
|
static String |
substring(String str,
int start,
int end)
Gets a substring from the specified String avoiding exceptions. |
|
static String |
substringAfter(String str,
String separator)
Gets the substring after the first occurrence of a separator. |
|
static String |
substringAfterLast(String str,
String separator)
Gets the substring after the last occurrence of a separator. |
|
static String |
substringBefore(String str,
String separator)
Gets the substring before the first occurrence of a separator. |
|
static String |
substringBeforeLast(String str,
String separator)
Gets the substring before the last occurrence of a separator. |
|
static String |
substringBetween(String str,
String tag)
Gets the String that is nested in between two instances of the same String. |
|
static String |
substringBetween(String str,
String open,
String close)
Gets the String that is nested in between two Strings. |
|
static String[] |
substringsBetween(String str,
String open,
String close)
Searches a String for substrings delimited by a start and end tag, returning all matching substrings in an array. |
|
static String |
swapCase(String str)
Swaps the case of a String changing upper and title case to lower case, and lower case to upper case. |
|
static String |
trim(String str)
Removes control characters (char <= 32) from both ends of this String, handling null by returning
null. |
|
static String |
trimToEmpty(String str)
Removes control characters (char <= 32) from both ends of this String returning an empty String ("") if the String is empty ("") after the trim or if it is null. |
|
static String |
trimToNull(String str)
Removes control characters (char <= 32) from both ends of this String returning null if the String is
empty ("") after the trim or if it is null. |
|
static String |
uncapitalize(CharSequence cs)
Uncapitalizes a CharSequence changing the first letter to title case as per Character.toLowerCase(char). |
|
static String |
upperCase(String str)
Converts a String to upper case as per String.toUpperCase(). |
|
static String |
upperCase(String str,
Locale locale)
Converts a String to upper case as per String.toUpperCase(Locale). |
|
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
|---|
public static final String EMPTY
"".
public static final int INDEX_NOT_FOUND
| Constructor Detail |
|---|
public StringUtils()
StringUtils instances should NOT be constructed in
standard programming. Instead, the class should be used as
StringUtils.trim(" foo ");.
This constructor is public to permit tools that require a JavaBean instance to operate.
| Method Detail |
|---|
public static boolean isEmpty(CharSequence cs)
Checks if a CharSequence is empty ("") or null.
StringUtils.isEmpty(null) = true
StringUtils.isEmpty("") = true
StringUtils.isEmpty(" ") = false
StringUtils.isEmpty("bob") = false
StringUtils.isEmpty(" bob ") = false
NOTE: This method changed in Lang version 2.0. It no longer trims the CharSequence. That functionality is available in isBlank().
cs - the CharSequence to check, may be null
true if the CharSequence is empty or nullpublic static boolean isNotEmpty(CharSequence cs)
Checks if a CharSequence is not empty ("") and not null.
StringUtils.isNotEmpty(null) = false
StringUtils.isNotEmpty("") = false
StringUtils.isNotEmpty(" ") = true
StringUtils.isNotEmpty("bob") = true
StringUtils.isNotEmpty(" bob ") = true
cs - the CharSequence to check, may be null
true if the CharSequence is not empty and not nullpublic static boolean isBlank(CharSequence cs)
Checks if a CharSequence is whitespace, empty ("") or null.
StringUtils.isBlank(null) = true
StringUtils.isBlank("") = true
StringUtils.isBlank(" ") = true
StringUtils.isBlank("bob") = false
StringUtils.isBlank(" bob ") = false
cs - the CharSequence to check, may be null
true if the CharSequence is null, empty or whitespacepublic static boolean isNotBlank(CharSequence cs)
Checks if a CharSequence is not empty (""), not null and not whitespace only.
StringUtils.isNotBlank(null) = false
StringUtils.isNotBlank("") = false
StringUtils.isNotBlank(" ") = false
StringUtils.isNotBlank("bob") = true
StringUtils.isNotBlank(" bob ") = true
cs - the CharSequence to check, may be null
true if the CharSequence is
not empty and not null and not whitespacepublic static String trim(String str)
Removes control characters (char <= 32) from both
ends of this String, handling null by returning
null.
The String is trimmed using String.trim().
Trim removes start and end characters <= 32.
To strip whitespace use strip(String).
To trim your choice of characters, use the
strip(String, String) methods.
StringUtils.trim(null) = null
StringUtils.trim("") = ""
StringUtils.trim(" ") = ""
StringUtils.trim("abc") = "abc"
StringUtils.trim(" abc ") = "abc"
str - the String to be trimmed, may be null
null if null String inputpublic static String trimToNull(String str)
Removes control characters (char <= 32) from both
ends of this String returning null if the String is
empty ("") after the trim or if it is null.
The String is trimmed using String.trim().
Trim removes start and end characters <= 32.
To strip whitespace use stripToNull(String).
StringUtils.trimToNull(null) = null
StringUtils.trimToNull("") = null
StringUtils.trimToNull(" ") = null
StringUtils.trimToNull("abc") = "abc"
StringUtils.trimToNull(" abc ") = "abc"
str - the String to be trimmed, may be null
null if only chars <= 32, empty or null String inputpublic static String trimToEmpty(String str)
Removes control characters (char <= 32) from both
ends of this String returning an empty String ("") if the String
is empty ("") after the trim or if it is null.
The String is trimmed using String.trim().
Trim removes start and end characters <= 32.
To strip whitespace use stripToEmpty(String).
StringUtils.trimToEmpty(null) = ""
StringUtils.trimToEmpty("") = ""
StringUtils.trimToEmpty(" ") = ""
StringUtils.trimToEmpty("abc") = "abc"
StringUtils.trimToEmpty(" abc ") = "abc"
str - the String to be trimmed, may be null
null inputpublic static String strip(String str)
Strips whitespace from the start and end of a String.
This is similar to trim(String) but removes whitespace.
Whitespace is defined by Character.isWhitespace(char).
A null input String returns null.
StringUtils.strip(null) = null
StringUtils.strip("") = ""
StringUtils.strip(" ") = ""
StringUtils.strip("abc") = "abc"
StringUtils.strip(" abc") = "abc"
StringUtils.strip("abc ") = "abc"
StringUtils.strip(" abc ") = "abc"
StringUtils.strip(" ab c ") = "ab c"
str - the String to remove whitespace from, may be null
null if null String inputpublic static String stripToNull(String str)
Strips whitespace from the start and end of a String returning
null if the String is empty ("") after the strip.
This is similar to trimToNull(String) but removes whitespace.
Whitespace is defined by Character.isWhitespace(char).
StringUtils.stripToNull(null) = null
StringUtils.stripToNull("") = null
StringUtils.stripToNull(" ") = null
StringUtils.stripToNull("abc") = "abc"
StringUtils.stripToNull(" abc") = "abc"
StringUtils.stripToNull("abc ") = "abc"
StringUtils.stripToNull(" abc ") = "abc"
StringUtils.stripToNull(" ab c ") = "ab c"
str - the String to be stripped, may be null
null if whitespace, empty or null String inputpublic static String stripToEmpty(String str)
Strips whitespace from the start and end of a String returning
an empty String if null input.
This is similar to trimToEmpty(String) but removes whitespace.
Whitespace is defined by Character.isWhitespace(char).
StringUtils.stripToEmpty(null) = ""
StringUtils.stripToEmpty("") = ""
StringUtils.stripToEmpty(" ") = ""
StringUtils.stripToEmpty("abc") = "abc"
StringUtils.stripToEmpty(" abc") = "abc"
StringUtils.stripToEmpty("abc ") = "abc"
StringUtils.stripToEmpty(" abc ") = "abc"
StringUtils.stripToEmpty(" ab c ") = "ab c"
str - the String to be stripped, may be null
null input
public static String strip(String str,
String stripChars)
Strips any of a set of characters from the start and end of a String.
This is similar to String.trim() but allows the characters
to be stripped to be controlled.
A null input String returns null.
An empty string ("") input returns the empty string.
If the stripChars String is null, whitespace is
stripped as defined by Character.isWhitespace(char).
Alternatively use strip(String).
StringUtils.strip(null, *) = null
StringUtils.strip("", *) = ""
StringUtils.strip("abc", null) = "abc"
StringUtils.strip(" abc", null) = "abc"
StringUtils.strip("abc ", null) = "abc"
StringUtils.strip(" abc ", null) = "abc"
StringUtils.strip(" abcyx", "xyz") = " abc"
str - the String to remove characters from, may be nullstripChars - the characters to remove, null treated as whitespace
null if null String input
public static String stripStart(String str,
String stripChars)
Strips any of a set of characters from the start of a String.
A null input String returns null.
An empty string ("") input returns the empty string.
If the stripChars String is null, whitespace is
stripped as defined by Character.isWhitespace(char).
StringUtils.stripStart(null, *) = null
StringUtils.stripStart("", *) = ""
StringUtils.stripStart("abc", "") = "abc"
StringUtils.stripStart("abc", null) = "abc"
StringUtils.stripStart(" abc", null) = "abc"
StringUtils.stripStart("abc ", null) = "abc "
StringUtils.stripStart(" abc ", null) = "abc "
StringUtils.stripStart("yxabc ", "xyz") = "abc "
str - the String to remove characters from, may be nullstripChars - the characters to remove, null treated as whitespace
null if null String input
public static String stripEnd(String str,
String stripChars)
Strips any of a set of characters from the end of a String.
A null input String returns null.
An empty string ("") input returns the empty string.
If the stripChars String is null, whitespace is
stripped as defined by Character.isWhitespace(char).
StringUtils.stripEnd(null, *) = null
StringUtils.stripEnd("", *) = ""
StringUtils.stripEnd("abc", "") = "abc"
StringUtils.stripEnd("abc", null) = "abc"
StringUtils.stripEnd(" abc", null) = " abc"
StringUtils.stripEnd("abc ", null) = "abc"
StringUtils.stripEnd(" abc ", null) = " abc"
StringUtils.stripEnd(" abcyx", "xyz") = " abc"
str - the String to remove characters from, may be nullstripChars - the characters to remove, null treated as whitespace
null if null String inputpublic static String[] stripAll(String[] strs)
Strips whitespace from the start and end of every String in an array.
Whitespace is defined by Character.isWhitespace(char).
A new array is returned each time, except for length zero.
A null array will return null.
An empty array will return itself.
A null array entry will be ignored.
StringUtils.stripAll(null) = null StringUtils.stripAll([]) = [] StringUtils.stripAll(["abc", " abc"]) = ["abc", "abc"] StringUtils.stripAll(["abc ", null]) = ["abc", null]
strs - the array to remove whitespace from, may be null
null if null array input
public static String[] stripAll(String[] strs,
String stripChars)
Strips any of a set of characters from the start and end of every String in an array.
Whitespace is defined byCharacter.isWhitespace(char).
A new array is returned each time, except for length zero.
A null array will return null.
An empty array will return itself.
A null array entry will be ignored.
A null stripChars will strip whitespace as defined by
Character.isWhitespace(char).
StringUtils.stripAll(null, *) = null StringUtils.stripAll([], *) = [] StringUtils.stripAll(["abc", " abc"], null) = ["abc", "abc"] StringUtils.stripAll(["abc ", null], null) = ["abc", null] StringUtils.stripAll(["abc ", null], "yz") = ["abc ", null] StringUtils.stripAll(["yabcz", null], "yz") = ["abc", null]
strs - the array to remove characters from, may be nullstripChars - the characters to remove, null treated as whitespace
null if null array inputpublic static String stripAccents(String input)
Removes the accents from a string.
NOTE: This is a JDK 1.6 method, it will fail on JDK 1.5.
StringUtils.stripAccents(null) = null
StringUtils.stripAccents("") = ""
StringUtils.stripAccents("control") = "control"
StringUtils.stripAccents("&ecute;clair") = "eclair"
input - String to be stripped
public static boolean equals(CharSequence cs1,
CharSequence cs2)
Compares two CharSequences, returning true if they are equal.
nulls are handled without exceptions. Two null
references are considered to be equal. The comparison is case sensitive.
StringUtils.equals(null, null) = true
StringUtils.equals(null, "abc") = false
StringUtils.equals("abc", null) = false
StringUtils.equals("abc", "abc") = true
StringUtils.equals("abc", "ABC") = false
cs1 - the first CharSequence, may be nullcs2 - the second CharSequence, may be null
true if the CharSequences are equal, case sensitive, or
both nullString.equals(Object)
public static boolean equalsIgnoreCase(String str1,
String str2)
Compares two Strings, returning true if they are equal ignoring
the case.
nulls are handled without exceptions. Two null
references are considered equal. Comparison is case insensitive.
StringUtils.equalsIgnoreCase(null, null) = true
StringUtils.equalsIgnoreCase(null, "abc") = false
StringUtils.equalsIgnoreCase("abc", null) = false
StringUtils.equalsIgnoreCase("abc", "abc") = true
StringUtils.equalsIgnoreCase("abc", "ABC") = true
str1 - the first String, may be nullstr2 - the second String, may be null
true if the Strings are equal, case insensitive, or
both nullString.equalsIgnoreCase(String)
public static int indexOf(String str,
int searchChar)
Finds the first index within a String, handling null.
This method uses String.indexOf(int).
A null or empty ("") String will return INDEX_NOT_FOUND (-1).
StringUtils.indexOf(null, *) = -1
StringUtils.indexOf("", *) = -1
StringUtils.indexOf("aabaabaa", 'a') = 0
StringUtils.indexOf("aabaabaa", 'b') = 2
str - the String to check, may be nullsearchChar - the character to find
null string input
public static int indexOf(String str,
int searchChar,
int startPos)
Finds the first index within a String from a start position,
handling null.
This method uses String.indexOf(int, int).
A null or empty ("") String will return (INDEX_NOT_FOUND) -1.
A negative start position is treated as zero.
A start position greater than the string length returns -1.
StringUtils.indexOf(null, *, *) = -1
StringUtils.indexOf("", *, *) = -1
StringUtils.indexOf("aabaabaa", 'b', 0) = 2
StringUtils.indexOf("aabaabaa", 'b', 3) = 5
StringUtils.indexOf("aabaabaa", 'b', 9) = -1
StringUtils.indexOf("aabaabaa", 'b', -1) = 2
str - the String to check, may be nullsearchChar - the character to findstartPos - the start position, negative treated as zero
null string input
public static int indexOf(String str,
String searchStr)
Finds the first index within a String, handling null.
This method uses String.indexOf(String).
A null String will return -1.
StringUtils.indexOf(null, *) = -1
StringUtils.indexOf(*, null) = -1
StringUtils.indexOf("", "") = 0
StringUtils.indexOf("", *) = -1 (except when * = "")
StringUtils.indexOf("aabaabaa", "a") = 0
StringUtils.indexOf("aabaabaa", "b") = 2
StringUtils.indexOf("aabaabaa", "ab") = 1
StringUtils.indexOf("aabaabaa", "") = 0
str - the String to check, may be nullsearchStr - the String to find, may be null
null string input
public static int indexOf(String str,
String searchStr,
int startPos)
Finds the first index within a String, handling null.
This method uses String.indexOf(String, int).
A null String will return -1.
A negative start position is treated as zero.
An empty ("") search String always matches.
A start position greater than the string length only matches
an empty search String.
StringUtils.indexOf(null, *, *) = -1
StringUtils.indexOf(*, null, *) = -1
StringUtils.indexOf("", "", 0) = 0
StringUtils.indexOf("", *, 0) = -1 (except when * = "")
StringUtils.indexOf("aabaabaa", "a", 0) = 0
StringUtils.indexOf("aabaabaa", "b", 0) = 2
StringUtils.indexOf("aabaabaa", "ab", 0) = 1
StringUtils.indexOf("aabaabaa", "b", 3) = 5
StringUtils.indexOf("aabaabaa", "b", 9) = -1
StringUtils.indexOf("aabaabaa", "b", -1) = 2
StringUtils.indexOf("aabaabaa", "", 2) = 2
StringUtils.indexOf("abc", "", 9) = 3
str - the String to check, may be nullsearchStr - the String to find, may be nullstartPos - the start position, negative treated as zero
null string input
public static int ordinalIndexOf(String str,
String searchStr,
int ordinal)
Finds the n-th index within a String, handling null.
This method uses String.indexOf(String).
A null String will return -1.
StringUtils.ordinalIndexOf(null, *, *) = -1
StringUtils.ordinalIndexOf(*, null, *) = -1
StringUtils.ordinalIndexOf("", "", *) = 0
StringUtils.ordinalIndexOf("aabaabaa", "a", 1) = 0
StringUtils.ordinalIndexOf("aabaabaa", "a", 2) = 1
StringUtils.ordinalIndexOf("aabaabaa", "b", 1) = 2
StringUtils.ordinalIndexOf("aabaabaa", "b", 2) = 5
StringUtils.ordinalIndexOf("aabaabaa", "ab", 1) = 1
StringUtils.ordinalIndexOf("aabaabaa", "ab", 2) = 4
StringUtils.ordinalIndexOf("aabaabaa", "", 1) = 0
StringUtils.ordinalIndexOf("aabaabaa", "", 2) = 0
Note that 'head(String str, int n)' may be implemented as:
str.substring(0, lastOrdinalIndexOf(str, "\n", n))
str - the String to check, may be nullsearchStr - the String to find, may be nullordinal - the n-th searchStr to find
-1 (INDEX_NOT_FOUND) if no match or null string input
public static int indexOfIgnoreCase(String str,
String searchStr)
Case in-sensitive find of the first index within a String.
A null String will return -1.
A negative start position is treated as zero.
An empty ("") search String always matches.
A start position greater than the string length only matches
an empty search String.
StringUtils.indexOfIgnoreCase(null, *) = -1
StringUtils.indexOfIgnoreCase(*, null) = -1
StringUtils.indexOfIgnoreCase("", "") = 0
StringUtils.indexOfIgnoreCase("aabaabaa", "a") = 0
StringUtils.indexOfIgnoreCase("aabaabaa", "b") = 2
StringUtils.indexOfIgnoreCase("aabaabaa", "ab") = 1
str - the String to check, may be nullsearchStr - the String to find, may be null
null string input
public static int indexOfIgnoreCase(String str,
String searchStr,
int startPos)
Case in-sensitive find of the first index within a String from the specified position.
A null String will return -1.
A negative start position is treated as zero.
An empty ("") search String always matches.
A start position greater than the string length only matches
an empty search String.
StringUtils.indexOfIgnoreCase(null, *, *) = -1
StringUtils.indexOfIgnoreCase(*, null, *) = -1
StringUtils.indexOfIgnoreCase("", "", 0) = 0
StringUtils.indexOfIgnoreCase("aabaabaa", "A", 0) = 0
StringUtils.indexOfIgnoreCase("aabaabaa", "B", 0) = 2
StringUtils.indexOfIgnoreCase("aabaabaa", "AB", 0) = 1
StringUtils.indexOfIgnoreCase("aabaabaa", "B", 3) = 5
StringUtils.indexOfIgnoreCase("aabaabaa", "B", 9) = -1
StringUtils.indexOfIgnoreCase("aabaabaa", "B", -1) = 2
StringUtils.indexOfIgnoreCase("aabaabaa", "", 2) = 2
StringUtils.indexOfIgnoreCase("abc", "", 9) = 3
str - the String to check, may be nullsearchStr - the String to find, may be nullstartPos - the start position, negative treated as zero
null string input
public static int lastIndexOf(String str,
int searchChar)
Finds the last index within a String, handling null.
This method uses String.lastIndexOf(int).
A null or empty ("") String will return -1.
StringUtils.lastIndexOf(null, *) = -1
StringUtils.lastIndexOf("", *) = -1
StringUtils.lastIndexOf("aabaabaa", 'a') = 7
StringUtils.lastIndexOf("aabaabaa", 'b') = 5
str - the String to check, may be nullsearchChar - the character to find
null string input
public static int lastIndexOf(String str,
int searchChar,
int startPos)
Finds the last index within a String from a start position,
handling null.
This method uses String.lastIndexOf(int, int).
A null or empty ("") String will return -1.
A negative start position returns -1.
A start position greater than the string length searches the whole string.
StringUtils.lastIndexOf(null, *, *) = -1
StringUtils.lastIndexOf("", *, *) = -1
StringUtils.lastIndexOf("aabaabaa", 'b', 8) = 5
StringUtils.lastIndexOf("aabaabaa", 'b', 4) = 2
StringUtils.lastIndexOf("aabaabaa", 'b', 0) = -1
StringUtils.lastIndexOf("aabaabaa", 'b', 9) = 5
StringUtils.lastIndexOf("aabaabaa", 'b', -1) = -1
StringUtils.lastIndexOf("aabaabaa", 'a', 0) = 0
str - the String to check, may be nullsearchChar - the character to findstartPos - the start position
null string input
public static int lastIndexOf(String str,
String searchStr)
Finds the last index within a String, handling null.
This method uses String.lastIndexOf(String).
A null String will return -1.
StringUtils.lastIndexOf(null, *) = -1
StringUtils.lastIndexOf(*, null) = -1
StringUtils.lastIndexOf("", "") = 0
StringUtils.lastIndexOf("aabaabaa", "a") = 7
StringUtils.lastIndexOf("aabaabaa", "b") = 5
StringUtils.lastIndexOf("aabaabaa", "ab") = 4
StringUtils.lastIndexOf("aabaabaa", "") = 8
str - the String to check, may be nullsearchStr - the String to find, may be null
null string input
public static int lastOrdinalIndexOf(String str,
String searchStr,
int ordinal)
Finds the n-th last index within a String, handling null.
This method uses String.lastIndexOf(String).
A null String will return -1.
StringUtils.lastOrdinalIndexOf(null, *, *) = -1
StringUtils.lastOrdinalIndexOf(*, null, *) = -1
StringUtils.lastOrdinalIndexOf("", "", *) = 0
StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 1) = 7
StringUtils.lastOrdinalIndexOf("aabaabaa", "a", 2) = 6
StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 1) = 5
StringUtils.lastOrdinalIndexOf("aabaabaa", "b", 2) = 2
StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 1) = 4
StringUtils.lastOrdinalIndexOf("aabaabaa", "ab", 2) = 1
StringUtils.lastOrdinalIndexOf("aabaabaa", "", 1) = 8
StringUtils.lastOrdinalIndexOf("aabaabaa", "", 2) = 8
Note that 'tail(String str, int n)' may be implemented as:
str.substring(lastOrdinalIndexOf(str, "\n", n) + 1)
str - the String to check, may be nullsearchStr - the String to find, may be nullordinal - the n-th last searchStr to find
-1 (INDEX_NOT_FOUND) if no match or null string input
public static int lastIndexOf(String str,
String searchStr,
int startPos)
Finds the first index within a String, handling null.
This method uses String.lastIndexOf(String, int).
A null String will return -1.
A negative start position returns -1.
An empty ("") search String always matches unless the start position is negative.
A start position greater than the string length searches the whole string.
StringUtils.lastIndexOf(null, *, *) = -1
StringUtils.lastIndexOf(*, null, *) = -1
StringUtils.lastIndexOf("aabaabaa", "a", 8) = 7
StringUtils.lastIndexOf("aabaabaa", "b", 8) = 5
StringUtils.lastIndexOf("aabaabaa", "ab", 8) = 4
StringUtils.lastIndexOf("aabaabaa", "b", 9) = 5
StringUtils.lastIndexOf("aabaabaa", "b", -1) = -1
StringUtils.lastIndexOf("aabaabaa", "a", 0) = 0
StringUtils.lastIndexOf("aabaabaa", "b", 0) = -1
str - the String to check, may be nullsearchStr - the String to find, may be nullstartPos - the start position, negative treated as zero
null string input
public static int lastIndexOfIgnoreCase(String str,
String searchStr)
Case in-sensitive find of the last index within a String.
A null String will return -1.
A negative start position returns -1.
An empty ("") search String always matches unless the start position is negative.
A start position greater than the string length searches the whole string.
StringUtils.lastIndexOfIgnoreCase(null, *) = -1
StringUtils.lastIndexOfIgnoreCase(*, null) = -1
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A") = 7
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B") = 5
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "AB") = 4
str - the String to check, may be nullsearchStr - the String to find, may be null
null string input
public static int lastIndexOfIgnoreCase(String str,
String searchStr,
int startPos)
Case in-sensitive find of the last index within a String from the specified position.
A null String will return -1.
A negative start position returns -1.
An empty ("") search String always matches unless the start position is negative.
A start position greater than the string length searches the whole string.
StringUtils.lastIndexOfIgnoreCase(null, *, *) = -1
StringUtils.lastIndexOfIgnoreCase(*, null, *) = -1
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A", 8) = 7
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 8) = 5
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "AB", 8) = 4
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 9) = 5
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", -1) = -1
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "A", 0) = 0
StringUtils.lastIndexOfIgnoreCase("aabaabaa", "B", 0) = -1
str - the String to check, may be nullsearchStr - the String to find, may be nullstartPos - the start position
null string input
public static boolean contains(String str,
int searchChar)
Checks if String contains a search character, handling null.
This method uses String.indexOf(int).
A null or empty ("") String will return false.
StringUtils.contains(null, *) = false
StringUtils.contains("", *) = false
StringUtils.contains("abc", 'a') = true
StringUtils.contains("abc", 'z') = false
str - the String to check, may be nullsearchChar - the character to find
null string input
public static boolean contains(String str,
String searchStr)
Checks if String contains a search String, handling null.
This method uses String.indexOf(String).
A null String will return false.
StringUtils.contains(null, *) = false
StringUtils.contains(*, null) = false
StringUtils.contains("", "") = true
StringUtils.contains("abc", "") = true
StringUtils.contains("abc", "a") = true
StringUtils.contains("abc", "z") = false
str - the String to check, may be nullsearchStr - the String to find, may be null
null string input
public static boolean containsIgnoreCase(String str,
String searchStr)
Checks if String contains a search String irrespective of case,
handling null. Case-insensitivity is defined as by
String.equalsIgnoreCase(String).
A null String will return false.
StringUtils.contains(null, *) = false
StringUtils.contains(*, null) = false
StringUtils.contains("", "") = true
StringUtils.contains("abc", "") = true
StringUtils.contains("abc", "a") = true
StringUtils.contains("abc", "z") = false
StringUtils.contains("abc", "A") = true
StringUtils.contains("abc", "Z") = false
str - the String to check, may be nullsearchStr - the String to find, may be null
null string inputpublic static boolean containsWhitespace(String str)
str - the String to check (may be null)
true if the String is not empty and
contains at least 1 whitespace characterCharacter.isWhitespace(char)
public static int indexOfAny(CharSequence cs,
char[] searchChars)
Search a CharSequence to find the first index of any character in the given set of characters.
A null String will return -1.
A null or zero length search array will return -1.
StringUtils.indexOfAny(null, *) = -1
StringUtils.indexOfAny("", *) = -1
StringUtils.indexOfAny(*, null) = -1
StringUtils.indexOfAny(*, []) = -1
StringUtils.indexOfAny("zzabyycdxx",['z','a']) = 0
StringUtils.indexOfAny("zzabyycdxx",['b','y']) = 3
StringUtils.indexOfAny("aba", ['z']) = -1
cs - the CharSequence to check, may be nullsearchChars - the chars to search for, may be null
public static int indexOfAny(CharSequence cs,
String searchChars)
Search a CharSequence to find the first index of any character in the given set of characters.
A null String will return -1.
A null search string will return -1.
StringUtils.indexOfAny(null, *) = -1
StringUtils.indexOfAny("", *) = -1
StringUtils.indexOfAny(*, null) = -1
StringUtils.indexOfAny(*, "") = -1
StringUtils.indexOfAny("zzabyycdxx", "za") = 0
StringUtils.indexOfAny("zzabyycdxx", "by") = 3
StringUtils.indexOfAny("aba","z") = -1
cs - the CharSequence to check, may be nullsearchChars - the chars to search for, may be null
public static boolean containsAny(String cs,
char[] searchChars)
Checks if the CharSequence contains any character in the given set of characters.
A null CharSequence will return false.
A null or zero length search array will return false.
StringUtils.containsAny(null, *) = false
StringUtils.containsAny("", *) = false
StringUtils.containsAny(*, null) = false
StringUtils.containsAny(*, []) = false
StringUtils.containsAny("zzabyycdxx",['z','a']) = true
StringUtils.containsAny("zzabyycdxx",['b','y']) = true
StringUtils.containsAny("aba", ['z']) = false
cs - the CharSequence to check, may be nullsearchChars - the chars to search for, may be null
true if any of the chars are found,
false if no match or null input
public static boolean containsAny(String cs,
String searchChars)
Checks if the CharSequence contains any character in the given set of characters.
A null CharSequence will return false. A null search CharSequence will return
false.
StringUtils.containsAny(null, *) = false
StringUtils.containsAny("", *) = false
StringUtils.containsAny(*, null) = false
StringUtils.containsAny(*, "") = false
StringUtils.containsAny("zzabyycdxx", "za") = true
StringUtils.containsAny("zzabyycdxx", "by") = true
StringUtils.containsAny("aba","z") = false
cs - the CharSequence to check, may be nullsearchChars - the chars to search for, may be null
true if any of the chars are found, false if no match or null input
public static int indexOfAnyBut(CharSequence cs,
char[] searchChars)
Searches a CharSequence to find the first index of any character not in the given set of characters.
A null CharSequence will return -1.
A null or zero length search array will return -1.
StringUtils.indexOfAnyBut(null, *) = -1
StringUtils.indexOfAnyBut("", *) = -1
StringUtils.indexOfAnyBut(*, null) = -1
StringUtils.indexOfAnyBut(*, []) = -1
StringUtils.indexOfAnyBut("zzabyycdxx",'za') = 3
StringUtils.indexOfAnyBut("zzabyycdxx", '') = 0
StringUtils.indexOfAnyBut("aba", 'ab') = -1
cs - the CharSequence to check, may be nullsearchChars - the chars to search for, may be null
public static int indexOfAnyBut(String str,
String searchChars)
Search a String to find the first index of any character not in the given set of characters.
A null String will return -1.
A null search string will return -1.
StringUtils.indexOfAnyBut(null, *) = -1
StringUtils.indexOfAnyBut("", *) = -1
StringUtils.indexOfAnyBut(*, null) = -1
StringUtils.indexOfAnyBut(*, "") = -1
StringUtils.indexOfAnyBut("zzabyycdxx", "za") = 3
StringUtils.indexOfAnyBut("zzabyycdxx", "") = 0
StringUtils.indexOfAnyBut("aba","ab") = -1
str - the String to check, may be nullsearchChars - the chars to search for, may be null
public static boolean containsOnly(CharSequence cs,
char[] valid)
Checks if the CharSequence contains only certain characters.
A null CharSequence will return false.
A null valid character array will return false.
An empty CharSequence (length()=0) always returns true.
StringUtils.containsOnly(null, *) = false
StringUtils.containsOnly(*, null) = false
StringUtils.containsOnly("", *) = true
StringUtils.containsOnly("ab", '') = false
StringUtils.containsOnly("abab", 'abc') = true
StringUtils.containsOnly("ab1", 'abc') = false
StringUtils.containsOnly("abz", 'abc') = false
cs - the String to check, may be nullvalid - an array of valid chars, may be null
public static boolean containsOnly(CharSequence cs,
String validChars)
Checks if the CharSequence contains only certain characters.
A null CharSequence will return false.
A null valid character String will return false.
An empty String (length()=0) always returns true.
StringUtils.containsOnly(null, *) = false
StringUtils.containsOnly(*, null) = false
StringUtils.containsOnly("", *) = true
StringUtils.containsOnly("ab", "") = false
StringUtils.containsOnly("abab", "abc") = true
StringUtils.containsOnly("ab1", "abc") = false
StringUtils.containsOnly("abz", "abc") = false
cs - the CharSequence to check, may be nullvalidChars - a String of valid chars, may be null
public static boolean containsNone(CharSequence cs,
char[] searchChars)
Checks that the CharSequence does not contain certain characters.
A null CharSequence will return true.
A null invalid character array will return true.
An empty CharSequence (length()=0) always returns true.
StringUtils.containsNone(null, *) = true
StringUtils.containsNone(*, null) = true
StringUtils.containsNone("", *) = true
StringUtils.containsNone("ab", '') = true
StringUtils.containsNone("abab", 'xyz') = true
StringUtils.containsNone("ab1", 'xyz') = true
StringUtils.containsNone("abz", 'xyz') = false
cs - the CharSequence to check, may be nullsearchChars - an array of invalid chars, may be null
public static boolean containsNone(CharSequence cs,
String invalidChars)
Checks that the CharSequence does not contain certain characters.
A null CharSequence will return true.
A null invalid character array will return true.
An empty String ("") always returns true.
StringUtils.containsNone(null, *) = true
StringUtils.containsNone(*, null) = true
StringUtils.containsNone("", *) = true
StringUtils.containsNone("ab", "") = true
StringUtils.containsNone("abab", "xyz") = true
StringUtils.containsNone("ab1", "xyz") = true
StringUtils.containsNone("abz", "xyz") = false
cs - the CharSequence to check, may be nullinvalidChars - a String of invalid chars, may be null
public static int indexOfAny(String str,
String[] searchStrs)
Find the first index of any of a set of potential substrings.
A null String will return -1.
A null or zero length search array will return -1.
A null search array entry will be ignored, but a search
array containing "" will return 0 if str is not
null. This method uses String.indexOf(String).
StringUtils.indexOfAny(null, *) = -1
StringUtils.indexOfAny(*, null) = -1
StringUtils.indexOfAny(*, []) = -1
StringUtils.indexOfAny("zzabyycdxx", ["ab","cd"]) = 2
StringUtils.indexOfAny("zzabyycdxx", ["cd","ab"]) = 2
StringUtils.indexOfAny("zzabyycdxx", ["mn","op"]) = -1
StringUtils.indexOfAny("zzabyycdxx", ["zab","aby"]) = 1
StringUtils.indexOfAny("zzabyycdxx", [""]) = 0
StringUtils.indexOfAny("", [""]) = 0
StringUtils.indexOfAny("", ["a"]) = -1
str - the String to check, may be nullsearchStrs - the Strings to search for, may be null
public static int lastIndexOfAny(String str,
String[] searchStrs)
Find the latest index of any of a set of potential substrings.
A null String will return -1.
A null search array will return -1.
A null or zero length search array entry will be ignored,
but a search array containing "" will return the length of str
if str is not null. This method uses String.indexOf(String)
StringUtils.lastIndexOfAny(null, *) = -1
StringUtils.lastIndexOfAny(*, null) = -1
StringUtils.lastIndexOfAny(*, []) = -1
StringUtils.lastIndexOfAny(*, [null]) = -1
StringUtils.lastIndexOfAny("zzabyycdxx", ["ab","cd"]) = 6
StringUtils.lastIndexOfAny("zzabyycdxx", ["cd","ab"]) = 6
StringUtils.lastIndexOfAny("zzabyycdxx", ["mn","op"]) = -1
StringUtils.lastIndexOfAny("zzabyycdxx", ["mn","op"]) = -1
StringUtils.lastIndexOfAny("zzabyycdxx", ["mn",""]) = 10
str - the String to check, may be nullsearchStrs - the Strings to search for, may be null
public static String substring(String str,
int start)
Gets a substring from the specified String avoiding exceptions.
A negative start position can be used to start n
characters from the end of the String.
A null String will return null.
An empty ("") String will return "".
StringUtils.substring(null, *) = null
StringUtils.substring("", *) = ""
StringUtils.substring("abc", 0) = "abc"
StringUtils.substring("abc", 2) = "c"
StringUtils.substring("abc", 4) = ""
StringUtils.substring("abc", -2) = "bc"
StringUtils.substring("abc", -4) = "abc"
str - the String to get the substring from, may be nullstart - the position to start from, negative means
count back from the end of the String by this many characters
null if null String input
public static String substring(String str,
int start,
int end)
Gets a substring from the specified String avoiding exceptions.
A negative start position can be used to start/end n
characters from the end of the String.
The returned substring starts with the character in the start
position and ends before the end position. All position counting is
zero-based -- i.e., to start at the beginning of the string use
start = 0. Negative start and end positions can be used to
specify offsets relative to the end of the String.
If start is not strictly to the left of end, ""
is returned.
StringUtils.substring(null, *, *) = null
StringUtils.substring("", * , *) = "";
StringUtils.substring("abc", 0, 2) = "ab"
StringUtils.substring("abc", 2, 0) = ""
StringUtils.substring("abc", 2, 4) = "c"
StringUtils.substring("abc", 4, 6) = ""
StringUtils.substring("abc", 2, 2) = ""
StringUtils.substring("abc", -2, -1) = "b"
StringUtils.substring("abc", -4, 2) = "ab"
str - the String to get the substring from, may be nullstart - the position to start from, negative means
count back from the end of the String by this many charactersend - the position to end at (exclusive), negative means
count back from the end of the String by this many characters
null if null String input
public static String left(String str,
int len)
Gets the leftmost len characters of a String.
If len characters are not available, or the
String is null, the String will be returned without
an exception. An exception is thrown if len is negative.
StringUtils.left(null, *) = null
StringUtils.left(*, -ve) = ""
StringUtils.left("", *) = ""
StringUtils.left("abc", 0) = ""
StringUtils.left("abc", 2) = "ab"
StringUtils.left("abc", 4) = "abc"
str - the String to get the leftmost characters from, may be nulllen - the length of the required String, must be zero or positive
null if null String input
public static String right(String str,
int len)
Gets the rightmost len characters of a String.
If len characters are not available, or the String
is null, the String will be returned without an
an exception. An exception is thrown if len is negative.
StringUtils.right(null, *) = null
StringUtils.right(*, -ve) = ""
StringUtils.right("", *) = ""
StringUtils.right("abc", 0) = ""
StringUtils.right("abc", 2) = "bc"
StringUtils.right("abc", 4) = "abc"
str - the String to get the rightmost characters from, may be nulllen - the length of the required String, must be zero or positive
null if null String input
public static String mid(String str,
int pos,
int len)
Gets len characters from the middle of a String.
If len characters are not available, the remainder
of the String will be returned without an exception. If the
String is null, null will be returned.
An exception is thrown if len is negative.
StringUtils.mid(null, *, *) = null
StringUtils.mid(*, *, -ve) = ""
StringUtils.mid("", 0, *) = ""
StringUtils.mid("abc", 0, 2) = "ab"
StringUtils.mid("abc", 0, 4) = "abc"
StringUtils.mid("abc", 2, 4) = "c"
StringUtils.mid("abc", 4, 2) = ""
StringUtils.mid("abc", -2, 2) = "ab"
str - the String to get the characters from, may be nullpos - the position to start from, negative treated as zerolen - the length of the required String, must be zero or positive
null if null String input
public static String substringBefore(String str,
String separator)
Gets the substring before the first occurrence of a separator. The separator is not returned.
A null string input will return null.
An empty ("") string input will return the empty string.
A null separator will return the input string.
If nothing is found, the string input is returned.
StringUtils.substringBefore(null, *) = null
StringUtils.substringBefore("", *) = ""
StringUtils.substringBefore("abc", "a") = ""
StringUtils.substringBefore("abcba", "b") = "a"
StringUtils.substringBefore("abc", "c") = "ab"
StringUtils.substringBefore("abc", "d") = "abc"
StringUtils.substringBefore("abc", "") = ""
StringUtils.substringBefore("abc", null) = "abc"
str - the String to get a substring from, may be nullseparator - the String to search for, may be null
null if null String input
public static String substringAfter(String str,
String separator)
Gets the substring after the first occurrence of a separator. The separator is not returned.
A null string input will return null.
An empty ("") string input will return the empty string.
A null separator will return the empty string if the
input string is not null.
If nothing is found, the empty string is returned.
StringUtils.substringAfter(null, *) = null
StringUtils.substringAfter("", *) = ""
StringUtils.substringAfter(*, null) = ""
StringUtils.substringAfter("abc", "a") = "bc"
StringUtils.substringAfter("abcba", "b") = "cba"
StringUtils.substringAfter("abc", "c") = ""
StringUtils.substringAfter("abc", "d") = ""
StringUtils.substringAfter("abc", "") = "abc"
str - the String to get a substring from, may be nullseparator - the String to search for, may be null
null if null String input
public static String substringBeforeLast(String str,
String separator)
Gets the substring before the last occurrence of a separator. The separator is not returned.
A null string input will return null.
An empty ("") string input will return the empty string.
An empty or null separator will return the input string.
If nothing is found, the string input is returned.
StringUtils.substringBeforeLast(null, *) = null
StringUtils.substringBeforeLast("", *) = ""
StringUtils.substringBeforeLast("abcba", "b") = "abc"
StringUtils.substringBeforeLast("abc", "c") = "ab"
StringUtils.substringBeforeLast("a", "a") = ""
StringUtils.substringBeforeLast("a", "z") = "a"
StringUtils.substringBeforeLast("a", null) = "a"
StringUtils.substringBeforeLast("a", "") = "a"
str - the String to get a substring from, may be nullseparator - the String to search for, may be null
null if null String input
public static String substringAfterLast(String str,
String separator)
Gets the substring after the last occurrence of a separator. The separator is not returned.
A null string input will return null.
An empty ("") string input will return the empty string.
An empty or null separator will return the empty string if
the input string is not null.
If nothing is found, the empty string is returned.
StringUtils.substringAfterLast(null, *) = null
StringUtils.substringAfterLast("", *) = ""
StringUtils.substringAfterLast(*, "") = ""
StringUtils.substringAfterLast(*, null) = ""
StringUtils.substringAfterLast("abc", "a") = "bc"
StringUtils.substringAfterLast("abcba", "b") = "a"
StringUtils.substringAfterLast("abc", "c") = ""
StringUtils.substringAfterLast("a", "a") = ""
StringUtils.substringAfterLast("a", "z") = ""
str - the String to get a substring from, may be nullseparator - the String to search for, may be null
null if null String input
public static String substringBetween(String str,
String tag)
Gets the String that is nested in between two instances of the same String.
A null input String returns null.
A null tag returns null.
StringUtils.substringBetween(null, *) = null
StringUtils.substringBetween("", "") = ""
StringUtils.substringBetween("", "tag") = null
StringUtils.substringBetween("tagabctag", null) = null
StringUtils.substringBetween("tagabctag", "") = ""
StringUtils.substringBetween("tagabctag", "tag") = "abc"
str - the String containing the substring, may be nulltag - the String before and after the substring, may be null
null if no match
public static String substringBetween(String str,
String open,
String close)
Gets the String that is nested in between two Strings. Only the first match is returned.
A null input String returns null.
A null open/close returns null (no match).
An empty ("") open and close returns an empty string.
StringUtils.substringBetween("wx[b]yz", "[", "]") = "b"
StringUtils.substringBetween(null, *, *) = null
StringUtils.substringBetween(*, null, *) = null
StringUtils.substringBetween(*, *, null) = null
StringUtils.substringBetween("", "", "") = ""
StringUtils.substringBetween("", "", "]") = null
StringUtils.substringBetween("", "[", "]") = null
StringUtils.substringBetween("yabcz", "", "") = ""
StringUtils.substringBetween("yabcz", "y", "z") = "abc"
StringUtils.substringBetween("yabczyabcz", "y", "z") = "abc"
str - the String containing the substring, may be nullopen - the String before the substring, may be nullclose - the String after the substring, may be null
null if no match
public static String[] substringsBetween(String str,
String open,
String close)
Searches a String for substrings delimited by a start and end tag, returning all matching substrings in an array.
A null input String returns null.
A null open/close returns null (no match).
An empty ("") open/close returns null (no match).
StringUtils.substringsBetween("[a][b][c]", "[", "]") = ["a","b","c"]
StringUtils.substringsBetween(null, *, *) = null
StringUtils.substringsBetween(*, null, *) = null
StringUtils.substringsBetween(*, *, null) = null
StringUtils.substringsBetween("", "[", "]") = []
str - the String containing the substrings, null returns null, empty returns emptyopen - the String identifying the start of the substring, empty returns nullclose - the String identifying the end of the substring, empty returns null
null if no matchpublic static String[] split(String str)
Splits the provided text into an array, using whitespace as the
separator.
Whitespace is defined by Character.isWhitespace(char).
The separator is not included in the returned String array. Adjacent separators are treated as one separator. For more control over the split use the StrTokenizer class.
A null input String returns null.
StringUtils.split(null) = null
StringUtils.split("") = []
StringUtils.split("abc def") = ["abc", "def"]
StringUtils.split("abc def") = ["abc", "def"]
StringUtils.split(" abc ") = ["abc"]
str - the String to parse, may be null
null if null String input
public static String[] split(String str,
char separatorChar)
Splits the provided text into an array, separator specified. This is an alternative to using StringTokenizer.
The separator is not included in the returned String array. Adjacent separators are treated as one separator. For more control over the split use the StrTokenizer class.
A null input String returns null.
StringUtils.split(null, *) = null
StringUtils.split("", *) = []
StringUtils.split("a.b.c", '.') = ["a", "b", "c"]
StringUtils.split("a..b.c", '.') = ["a", "b", "c"]
StringUtils.split("a:b:c", '.') = ["a:b:c"]
StringUtils.split("a b c", ' ') = ["a", "b", "c"]
str - the String to parse, may be nullseparatorChar - the character used as the delimiter
null if null String input
public static String[] split(String str,
String separatorChars)
Splits the provided text into an array, separators specified. This is an alternative to using StringTokenizer.
The separator is not included in the returned String array. Adjacent separators are treated as one separator. For more control over the split use the StrTokenizer class.
A null input String returns null.
A null separatorChars splits on whitespace.
StringUtils.split(null, *) = null
StringUtils.split("", *) = []
StringUtils.split("abc def", null) = ["abc", "def"]
StringUtils.split("abc def", " ") = ["abc", "def"]
StringUtils.split("abc def", " ") = ["abc", "def"]
StringUtils.split("ab:cd:ef", ":") = ["ab", "cd", "ef"]
str - the String to parse, may be nullseparatorChars - the characters used as the delimiters,
null splits on whitespace
null if null String input
public static String[] split(String str,
String separatorChars,
int max)
Splits the provided text into an array with a maximum length, separators specified.
The separator is not included in the returned String array. Adjacent separators are treated as one separator.
A null input String returns null.
A null separatorChars splits on whitespace.
If more than max delimited substrings are found, the last
returned string includes all characters after the first max - 1
returned strings (including separator characters).
StringUtils.split(null, *, *) = null
StringUtils.split("", *, *) = []
StringUtils.split("ab de fg", null, 0) = ["ab", "cd", "ef"]
StringUtils.split("ab de fg", null, 0) = ["ab", "cd", "ef"]
StringUtils.split("ab:cd:ef", ":", 0) = ["ab", "cd", "ef"]
StringUtils.split("ab:cd:ef", ":", 2) = ["ab", "cd:ef"]
str - the String to parse, may be nullseparatorChars - the characters used as the delimiters,
null splits on whitespacemax - the maximum number of elements to include in the
array. A zero or negative value implies no limit
null if null String input
public static String[] splitByWholeSeparator(String str,
String separator)
Splits the provided text into an array, separator string specified.
The separator(s) will not be included in the returned String array. Adjacent separators are treated as one separator.
A null input String returns null.
A null separator splits on whitespace.
StringUtils.splitByWholeSeparator(null, *) = null
StringUtils.splitByWholeSeparator("", *) = []
StringUtils.splitByWholeSeparator("ab de fg", null) = ["ab", "de", "fg"]
StringUtils.splitByWholeSeparator("ab de fg", null) = ["ab", "de", "fg"]
StringUtils.splitByWholeSeparator("ab:cd:ef", ":") = ["ab", "cd", "ef"]
StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-") = ["ab", "cd", "ef"]
str - the String to parse, may be nullseparator - String containing the String to be used as a delimiter,
null splits on whitespace
null if null String was input
public static String[] splitByWholeSeparator(String str,
String separator,
int max)
Splits the provided text into an array, separator string specified.
Returns a maximum of max substrings.
The separator(s) will not be included in the returned String array. Adjacent separators are treated as one separator.
A null input String returns null.
A null separator splits on whitespace.
StringUtils.splitByWholeSeparator(null, *, *) = null
StringUtils.splitByWholeSeparator("", *, *) = []
StringUtils.splitByWholeSeparator("ab de fg", null, 0) = ["ab", "de", "fg"]
StringUtils.splitByWholeSeparator("ab de fg", null, 0) = ["ab", "de", "fg"]
StringUtils.splitByWholeSeparator("ab:cd:ef", ":", 2) = ["ab", "cd:ef"]
StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-", 5) = ["ab", "cd", "ef"]
StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-", 2) = ["ab", "cd-!-ef"]
str - the String to parse, may be nullseparator - String containing the String to be used as a delimiter,
null splits on whitespacemax - the maximum number of elements to include in the returned
array. A zero or negative value implies no limit.
null if null String was input
public static String[] splitByWholeSeparatorPreserveAllTokens(String str,
String separator)
Splits the provided text into an array, separator string specified.
The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. For more control over the split use the StrTokenizer class.
A null input String returns null.
A null separator splits on whitespace.
StringUtils.splitByWholeSeparatorPreserveAllTokens(null, *) = null
StringUtils.splitByWholeSeparatorPreserveAllTokens("", *) = []
StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null) = ["ab", "de", "fg"]
StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null) = ["ab", "", "", "de", "fg"]
StringUtils.splitByWholeSeparatorPreserveAllTokens("ab:cd:ef", ":") = ["ab", "cd", "ef"]
StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-") = ["ab", "cd", "ef"]
str - the String to parse, may be nullseparator - String containing the String to be used as a delimiter,
null splits on whitespace
null if null String was input
public static String[] splitByWholeSeparatorPreserveAllTokens(String str,
String separator,
int max)
Splits the provided text into an array, separator string specified.
Returns a maximum of max substrings.
The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. For more control over the split use the StrTokenizer class.
A null input String returns null.
A null separator splits on whitespace.
StringUtils.splitByWholeSeparatorPreserveAllTokens(null, *, *) = null
StringUtils.splitByWholeSeparatorPreserveAllTokens("", *, *) = []
StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null, 0) = ["ab", "de", "fg"]
StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null, 0) = ["ab", "", "", "de", "fg"]
StringUtils.splitByWholeSeparatorPreserveAllTokens("ab:cd:ef", ":", 2) = ["ab", "cd:ef"]
StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-", 5) = ["ab", "cd", "ef"]
StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-", 2) = ["ab", "cd-!-ef"]
str - the String to parse, may be nullseparator - String containing the String to be used as a delimiter,
null splits on whitespacemax - the maximum number of elements to include in the returned
array. A zero or negative value implies no limit.
null if null String was inputpublic static String[] splitPreserveAllTokens(String str)
Splits the provided text into an array, using whitespace as the
separator, preserving all tokens, including empty tokens created by
adjacent separators. This is an alternative to using StringTokenizer.
Whitespace is defined by Character.isWhitespace(char).
The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. For more control over the split use the StrTokenizer class.
A null input String returns null.
StringUtils.splitPreserveAllTokens(null) = null
StringUtils.splitPreserveAllTokens("") = []
StringUtils.splitPreserveAllTokens("abc def") = ["abc", "def"]
StringUtils.splitPreserveAllTokens("abc def") = ["abc", "", "def"]
StringUtils.splitPreserveAllTokens(" abc ") = ["", "abc", ""]
str - the String to parse, may be null
null if null String input
public static String[] splitPreserveAllTokens(String str,
char separatorChar)
Splits the provided text into an array, separator specified, preserving all tokens, including empty tokens created by adjacent separators. This is an alternative to using StringTokenizer.
The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. For more control over the split use the StrTokenizer class.
A null input String returns null.
StringUtils.splitPreserveAllTokens(null, *) = null
StringUtils.splitPreserveAllTokens("", *) = []
StringUtils.splitPreserveAllTokens("a.b.c", '.') = ["a", "b", "c"]
StringUtils.splitPreserveAllTokens("a..b.c", '.') = ["a", "", "b", "c"]
StringUtils.splitPreserveAllTokens("a:b:c", '.') = ["a:b:c"]
StringUtils.splitPreserveAllTokens("a\tb\nc", null) = ["a", "b", "c"]
StringUtils.splitPreserveAllTokens("a b c", ' ') = ["a", "b", "c"]
StringUtils.splitPreserveAllTokens("a b c ", ' ') = ["a", "b", "c", ""]
StringUtils.splitPreserveAllTokens("a b c ", ' ') = ["a", "b", "c", "", ""]
StringUtils.splitPreserveAllTokens(" a b c", ' ') = ["", a", "b", "c"]
StringUtils.splitPreserveAllTokens(" a b c", ' ') = ["", "", a", "b", "c"]
StringUtils.splitPreserveAllTokens(" a b c ", ' ') = ["", a", "b", "c", ""]
str - the String to parse, may be nullseparatorChar - the character used as the delimiter,
null splits on whitespace
null if null String input
public static String[] splitPreserveAllTokens(String str,
String separatorChars)
Splits the provided text into an array, separators specified, preserving all tokens, including empty tokens created by adjacent separators. This is an alternative to using StringTokenizer.
The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. For more control over the split use the StrTokenizer class.
A null input String returns null.
A null separatorChars splits on whitespace.
StringUtils.splitPreserveAllTokens(null, *) = null
StringUtils.splitPreserveAllTokens("", *) = []
StringUtils.splitPreserveAllTokens("abc def", null) = ["abc", "def"]
StringUtils.splitPreserveAllTokens("abc def", " ") = ["abc", "def"]
StringUtils.splitPreserveAllTokens("abc def", " ") = ["abc", "", def"]
StringUtils.splitPreserveAllTokens("ab:cd:ef", ":") = ["ab", "cd", "ef"]
StringUtils.splitPreserveAllTokens("ab:cd:ef:", ":") = ["ab", "cd", "ef", ""]
StringUtils.splitPreserveAllTokens("ab:cd:ef::", ":") = ["ab", "cd", "ef", "", ""]
StringUtils.splitPreserveAllTokens("ab::cd:ef", ":") = ["ab", "", cd", "ef"]
StringUtils.splitPreserveAllTokens(":cd:ef", ":") = ["", cd", "ef"]
StringUtils.splitPreserveAllTokens("::cd:ef", ":") = ["", "", cd", "ef"]
StringUtils.splitPreserveAllTokens(":cd:ef:", ":") = ["", cd", "ef", ""]
str - the String to parse, may be nullseparatorChars - the characters used as the delimiters,
null splits on whitespace
null if null String input
public static String[] splitPreserveAllTokens(String str,
String separatorChars,
int max)
Splits the provided text into an array with a maximum length, separators specified, preserving all tokens, including empty tokens created by adjacent separators.
The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. Adjacent separators are treated as one separator.
A null input String returns null.
A null separatorChars splits on whitespace.
If more than max delimited substrings are found, the last
returned string includes all characters after the first max - 1
returned strings (including separator characters).
StringUtils.splitPreserveAllTokens(null, *, *) = null
StringUtils.splitPreserveAllTokens("", *, *) = []
StringUtils.splitPreserveAllTokens("ab de fg", null, 0) = ["ab", "cd", "ef"]
StringUtils.splitPreserveAllTokens("ab de fg", null, 0) = ["ab", "cd", "ef"]
StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 0) = ["ab", "cd", "ef"]
StringUtils.splitPreserveAllTokens("ab:cd:ef", ":", 2) = ["ab", "cd:ef"]
StringUtils.splitPreserveAllTokens("ab de fg", null, 2) = ["ab", " de fg"]
StringUtils.splitPreserveAllTokens("ab de fg", null, 3) = ["ab", "", " de fg"]
StringUtils.splitPreserveAllTokens("ab de fg", null, 4) = ["ab", "", "", "de fg"]
str - the String to parse, may be nullseparatorChars - the characters used as the delimiters,
null splits on whitespacemax - the maximum number of elements to include in the
array. A zero or negative value implies no limit
null if null String inputpublic static String[] splitByCharacterType(String str)
Splits a String by Character type as returned by
java.lang.Character.getType(char). Groups of contiguous
characters of the same type are returned as complete tokens.
StringUtils.splitByCharacterType(null) = null
StringUtils.splitByCharacterType("") = []
StringUtils.splitByCharacterType("ab de fg") = ["ab", " ", "de", " ", "fg"]
StringUtils.splitByCharacterType("ab de fg") = ["ab", " ", "de", " ", "fg"]
StringUtils.splitByCharacterType("ab:cd:ef") = ["ab", ":", "cd", ":", "ef"]
StringUtils.splitByCharacterType("number5") = ["number", "5"]
StringUtils.splitByCharacterType("fooBar") = ["foo", "B", "ar"]
StringUtils.splitByCharacterType("foo200Bar") = ["foo", "200", "B", "ar"]
StringUtils.splitByCharacterType("ASFRules") = ["ASFR", "ules"]
str - the String to split, may be null
null if null String inputpublic static String[] splitByCharacterTypeCamelCase(String str)
Splits a String by Character type as returned by
java.lang.Character.getType(char). Groups of contiguous
characters of the same type are returned as complete tokens, with the
following exception: the character of type
Character.UPPERCASE_LETTER, if any, immediately
preceding a token of type Character.LOWERCASE_LETTER
will belong to the following token rather than to the preceding, if any,
Character.UPPERCASE_LETTER token.
StringUtils.splitByCharacterTypeCamelCase(null) = null
StringUtils.splitByCharacterTypeCamelCase("") = []
StringUtils.splitByCharacterTypeCamelCase("ab de fg") = ["ab", " ", "de", " ", "fg"]
StringUtils.splitByCharacterTypeCamelCase("ab de fg") = ["ab", " ", "de", " ", "fg"]
StringUtils.splitByCharacterTypeCamelCase("ab:cd:ef") = ["ab", ":", "cd", ":", "ef"]
StringUtils.splitByCharacterTypeCamelCase("number5") = ["number", "5"]
StringUtils.splitByCharacterTypeCamelCase("fooBar") = ["foo", "Bar"]
StringUtils.splitByCharacterTypeCamelCase("foo200Bar") = ["foo", "200", "Bar"]
StringUtils.splitByCharacterTypeCamelCase("ASFRules") = ["ASF", "Rules"]
str - the String to split, may be null
null if null String inputpublic static String concat(Object... elements)
Joins the provided elements into a single String.
No separator is added to the joined String. Null objects or empty string elements are represented by empty strings.
StringUtils.concat("a", "b", "c") = "abc"
StringUtils.concat(null, "", "a") = "a"
elements - the values to join together
public static String concatWith(String separator,
Object... elements)
Joins the provided elements into a single String, with the specified separator between each element.
No separator is added before or after the joined String. Null objects or empty string elements are represented by empty strings.
StringUtils.concatWith(".", "a", "b", "c") = "a.b.c"
StringUtils.concatWith("", null, "", "a") = "a"
separator - the value to put between elementselements - the values to join together
public static String join(Object[] array)
Joins the elements of the provided array into a single String containing the provided list of elements.
No separator is added to the joined String. Null objects or empty strings within the array are represented by empty strings.
StringUtils.join(null) = null StringUtils.join([]) = "" StringUtils.join([null]) = "" StringUtils.join(["a", "b", "c"]) = "abc" StringUtils.join([null, "", "a"]) = "a"
array - the array of values to join together, may be null
null if null array input
public static String join(Object[] array,
char separator)
Joins the elements of the provided array into a single String containing the provided list of elements.
No delimiter is added before or after the list. Null objects or empty strings within the array are represented by empty strings.
StringUtils.join(null, *) = null StringUtils.join([], *) = "" StringUtils.join([null], *) = "" StringUtils.join(["a", "b", "c"], ';') = "a;b;c" StringUtils.join(["a", "b", "c"], null) = "abc" StringUtils.join([null, "", "a"], ';') = ";;a"
array - the array of values to join together, may be nullseparator - the separator character to use
null if null array input
public static String join(Object[] array,
char separator,
int startIndex,
int endIndex)
Joins the elements of the provided array into a single String containing the provided list of elements.
No delimiter is added before or after the list. Null objects or empty strings within the array are represented by empty strings.
StringUtils.join(null, *) = null StringUtils.join([], *) = "" StringUtils.join([null], *) = "" StringUtils.join(["a", "b", "c"], ';') = "a;b;c" StringUtils.join(["a", "b", "c"], null) = "abc" StringUtils.join([null, "", "a"], ';') = ";;a"
array - the array of values to join together, may be nullseparator - the separator character to usestartIndex - the first index to start joining from. It is
an error to pass in an end index past the end of the arrayendIndex - the index to stop joining from (exclusive). It is
an error to pass in an end index past the end of the array
null if null array input
public static String join(Object[] array,
String separator)
Joins the elements of the provided array into a single String containing the provided list of elements.
No delimiter is added before or after the list.
A null separator is the same as an empty String ("").
Null objects or empty strings within the array are represented by
empty strings.
StringUtils.join(null, *) = null StringUtils.join([], *) = "" StringUtils.join([null], *) = "" StringUtils.join(["a", "b", "c"], "--") = "a--b--c" StringUtils.join(["a", "b", "c"], null) = "abc" StringUtils.join(["a", "b", "c"], "") = "abc" StringUtils.join([null, "", "a"], ',') = ",,a"
array - the array of values to join together, may be nullseparator - the separator character to use, null treated as ""
null if null array input
public static String join(Object[] array,
String separator,
int startIndex,
int endIndex)
Joins the elements of the provided array into a single String containing the provided list of elements.
No delimiter is added before or after the list.
A null separator is the same as an empty String ("").
Null objects or empty strings within the array are represented by
empty strings.
StringUtils.join(null, *) = null StringUtils.join([], *) = "" StringUtils.join([null], *) = "" StringUtils.join(["a", "b", "c"], "--") = "a--b--c" StringUtils.join(["a", "b", "c"], null) = "abc" StringUtils.join(["a", "b", "c"], "") = "abc" StringUtils.join([null, "", "a"], ',') = ",,a"
array - the array of values to join together, may be nullseparator - the separator character to use, null treated as ""startIndex - the first index to start joining from. It is
an error to pass in an end index past the end of the arrayendIndex - the index to stop joining from (exclusive). It is
an error to pass in an end index past the end of the array
null if null array input
public static String join(Iterator<?> iterator,
char separator)
Joins the elements of the provided Iterator into
a single String containing the provided elements.
No delimiter is added before or after the list. Null objects or empty strings within the iteration are represented by empty strings.
See the examples here: join(Object[],char).
iterator - the Iterator of values to join together, may be nullseparator - the separator character to use
null if null iterator input
public static String join(Iterator<?> iterator,
String separator)
Joins the elements of the provided Iterator into
a single String containing the provided elements.
No delimiter is added before or after the list.
A null separator is the same as an empty String ("").
See the examples here: join(Object[],String).
iterator - the Iterator of values to join together, may be nullseparator - the separator character to use, null treated as ""
null if null iterator input
public static String join(Iterable<?> iterable,
char separator)
Joins the elements of the provided Iterable into
a single String containing the provided elements.
No delimiter is added before or after the list. Null objects or empty strings within the iteration are represented by empty strings.
See the examples here: join(Object[],char).
iterable - the Iterable providing the values to join together, may be nullseparator - the separator character to use
null if null iterator input
public static String join(Iterable<?> iterable,
String separator)
Joins the elements of the provided Iterable into
a single String containing the provided elements.
No delimiter is added before or after the list.
A null separator is the same as an empty String ("").
See the examples here: join(Object[],String).
iterable - the Iterable providing the values to join together, may be nullseparator - the separator character to use, null treated as ""
null if null iterator inputpublic static String deleteWhitespace(String str)
Deletes all whitespaces from a String as defined by
Character.isWhitespace(char).
StringUtils.deleteWhitespace(null) = null
StringUtils.deleteWhitespace("") = ""
StringUtils.deleteWhitespace("abc") = "abc"
StringUtils.deleteWhitespace(" ab c ") = "abc"
str - the String to delete whitespace from, may be null
null if null String input
public static String removeStart(String str,
String remove)
Removes a substring only if it is at the begining of a source string, otherwise returns the source string.
A null source string will return null.
An empty ("") source string will return the empty string.
A null search string will return the source string.
StringUtils.removeStart(null, *) = null
StringUtils.removeStart("", *) = ""
StringUtils.removeStart(*, null) = *
StringUtils.removeStart("www.domain.com", "www.") = "domain.com"
StringUtils.removeStart("domain.com", "www.") = "domain.com"
StringUtils.removeStart("www.domain.com", "domain") = "www.domain.com"
StringUtils.removeStart("abc", "") = "abc"
str - the source String to search, may be nullremove - the String to search for and remove, may be null
null if null String input
public static String removeStartIgnoreCase(String str,
String remove)
Case insensitive removal of a substring if it is at the begining of a source string, otherwise returns the source string.
A null source string will return null.
An empty ("") source string will return the empty string.
A null search string will return the source string.
StringUtils.removeStartIgnoreCase(null, *) = null
StringUtils.removeStartIgnoreCase("", *) = ""
StringUtils.removeStartIgnoreCase(*, null) = *
StringUtils.removeStartIgnoreCase("www.domain.com", "www.") = "domain.com"
StringUtils.removeStartIgnoreCase("www.domain.com", "WWW.") = "domain.com"
StringUtils.removeStartIgnoreCase("domain.com", "www.") = "domain.com"
StringUtils.removeStartIgnoreCase("www.domain.com", "domain") = "www.domain.com"
StringUtils.removeStartIgnoreCase("abc", "") = "abc"
str - the source String to search, may be nullremove - the String to search for (case insensitive) and remove, may be null
null if null String input
public static String removeEnd(String str,
String remove)
Removes a substring only if it is at the end of a source string, otherwise returns the source string.
A null source string will return null.
An empty ("") source string will return the empty string.
A null search string will return the source string.
StringUtils.removeEnd(null, *) = null
StringUtils.removeEnd("", *) = ""
StringUtils.removeEnd(*, null) = *
StringUtils.removeEnd("www.domain.com", ".com.") = "www.domain.com"
StringUtils.removeEnd("www.domain.com", ".com") = "www.domain"
StringUtils.removeEnd("www.domain.com", "domain") = "www.domain.com"
StringUtils.removeEnd("abc", "") = "abc"
str - the source String to search, may be nullremove - the String to search for and remove, may be null
null if null String input
public static String removeEndIgnoreCase(String str,
String remove)
Case insensitive removal of a substring if it is at the end of a source string, otherwise returns the source string.
A null source string will return null.
An empty ("") source string will return the empty string.
A null search string will return the source string.
StringUtils.removeEndIgnoreCase(null, *) = null
StringUtils.removeEndIgnoreCase("", *) = ""
StringUtils.removeEndIgnoreCase(*, null) = *
StringUtils.removeEndIgnoreCase("www.domain.com", ".com.") = "www.domain.com"
StringUtils.removeEndIgnoreCase("www.domain.com", ".com") = "www.domain"
StringUtils.removeEndIgnoreCase("www.domain.com", "domain") = "www.domain.com"
StringUtils.removeEndIgnoreCase("abc", "") = "abc"
StringUtils.removeEndIgnoreCase("www.domain.com", ".COM") = "www.domain")
StringUtils.removeEndIgnoreCase("www.domain.COM", ".com") = "www.domain")
str - the source String to search, may be nullremove - the String to search for (case insensitive) and remove, may be null
null if null String input
public static String remove(String str,
String remove)
Removes all occurrences of a substring from within the source string.
A null source string will return null.
An empty ("") source string will return the empty string.
A null remove string will return the source string.
An empty ("") remove string will return the source string.
StringUtils.remove(null, *) = null
StringUtils.remove("", *) = ""
StringUtils.remove(*, null) = *
StringUtils.remove(*, "") = *
StringUtils.remove("queued", "ue") = "qd"
StringUtils.remove("queued", "zz") = "queued"
str - the source String to search, may be nullremove - the String to search for and remove, may be null
null if null String input
public static String remove(String str,
char remove)
Removes all occurrences of a character from within the source string.
A null source string will return null.
An empty ("") source string will return the empty string.
StringUtils.remove(null, *) = null
StringUtils.remove("", *) = ""
StringUtils.remove("queued", 'u') = "qeed"
StringUtils.remove("queued", 'z') = "queued"
str - the source String to search, may be nullremove - the char to search for and remove, may be null
null if null String input
public static String replaceOnce(String text,
String searchString,
String replacement)
Replaces a String with another String inside a larger String, once.
A null reference passed to this method is a no-op.
StringUtils.replaceOnce(null, *, *) = null
StringUtils.replaceOnce("", *, *) = ""
StringUtils.replaceOnce("any", null, *) = "any"
StringUtils.replaceOnce("any", *, null) = "any"
StringUtils.replaceOnce("any", "", *) = "any"
StringUtils.replaceOnce("aba", "a", null) = "aba"
StringUtils.replaceOnce("aba", "a", "") = "ba"
StringUtils.replaceOnce("aba", "a", "z") = "zba"
text - text to search and replace in, may be nullsearchString - the String to search for, may be nullreplacement - the String to replace with, may be null
null if null String inputreplace(String text, String searchString, String replacement, int max)
public static String replace(String text,
String searchString,
String replacement)
Replaces all occurrences of a String within another String.
A null reference passed to this method is a no-op.
StringUtils.replace(null, *, *) = null
StringUtils.replace("", *, *) = ""
StringUtils.replace("any", null, *) = "any"
StringUtils.replace("any", *, null) = "any"
StringUtils.replace("any", "", *) = "any"
StringUtils.replace("aba", "a", null) = "aba"
StringUtils.replace("aba", "a", "") = "b"
StringUtils.replace("aba", "a", "z") = "zbz"
text - text to search and replace in, may be nullsearchString - the String to search for, may be nullreplacement - the String to replace it with, may be null
null if null String inputreplace(String text, String searchString, String replacement, int max)
public static String replace(String text,
String searchString,
String replacement,
int max)
Replaces a String with another String inside a larger String,
for the first max values of the search String.
A null reference passed to this method is a no-op.
StringUtils.replace(null, *, *, *) = null
StringUtils.replace("", *, *, *) = ""
StringUtils.replace("any", null, *, *) = "any"
StringUtils.replace("any", *, null, *) = "any"
StringUtils.replace("any", "", *, *) = "any"
StringUtils.replace("any", *, *, 0) = "any"
StringUtils.replace("abaa", "a", null, -1) = "abaa"
StringUtils.replace("abaa", "a", "", -1) = "b"
StringUtils.replace("abaa", "a", "z", 0) = "abaa"
StringUtils.replace("abaa", "a", "z", 1) = "zbaa"
StringUtils.replace("abaa", "a", "z", 2) = "zbza"
StringUtils.replace("abaa", "a", "z", -1) = "zbzz"
text - text to search and replace in, may be nullsearchString - the String to search for, may be nullreplacement - the String to replace it with, may be nullmax - maximum number of values to replace, or -1 if no maximum
null if null String input
public static String replaceEach(String text,
String[] searchList,
String[] replacementList)
Replaces all occurrences of Strings within another String.
A null reference passed to this method is a no-op, or if
any "search string" or "string to replace" is null, that replace will be
ignored. This will not repeat. For repeating replaces, call the
overloaded method.
StringUtils.replaceEach(null, *, *) = null
StringUtils.replaceEach("", *, *) = ""
StringUtils.replaceEach("aba", null, null) = "aba"
StringUtils.replaceEach("aba", new String[0], null) = "aba"
StringUtils.replaceEach("aba", null, new String[0]) = "aba"
StringUtils.replaceEach("aba", new String[]{"a"}, null) = "aba"
StringUtils.replaceEach("aba", new String[]{"a"}, new String[]{""}) = "b"
StringUtils.replaceEach("aba", new String[]{null}, new String[]{"a"}) = "aba"
StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"}) = "wcte"
(example of how it does not repeat)
StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}) = "dcte"
text - text to search and replace in, no-op if nullsearchList - the Strings to search for, no-op if nullreplacementList - the Strings to replace them with, no-op if null
null if
null String input
IndexOutOfBoundsException - if the lengths of the arrays are not the same (null is ok,
and/or size 0)
public static String replaceEachRepeatedly(String text,
String[] searchList,
String[] replacementList)
Replaces all occurrences of Strings within another String.
A null reference passed to this method is a no-op, or if
any "search string" or "string to replace" is null, that replace will be
ignored. This will not repeat. For repeating replaces, call the
overloaded method.
StringUtils.replaceEach(null, *, *, *) = null
StringUtils.replaceEach("", *, *, *) = ""
StringUtils.replaceEach("aba", null, null, *) = "aba"
StringUtils.replaceEach("aba", new String[0], null, *) = "aba"
StringUtils.replaceEach("aba", null, new String[0], *) = "aba"
StringUtils.replaceEach("aba", new String[]{"a"}, null, *) = "aba"
StringUtils.replaceEach("aba", new String[]{"a"}, new String[]{""}, *) = "b"
StringUtils.replaceEach("aba", new String[]{null}, new String[]{"a"}, *) = "aba"
StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"w", "t"}, *) = "wcte"
(example of how it repeats)
StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}, false) = "dcte"
StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "t"}, true) = "tcte"
StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "ab"}, true) = IllegalArgumentException
StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "ab"}, false) = "dcabe"
text - text to search and replace in, no-op if nullsearchList - the Strings to search for, no-op if nullreplacementList - the Strings to replace them with, no-op if null
null if
null String input
IllegalArgumentException - if the search is repeating and there is an endless loop due
to outputs of one being inputs to another
IndexOutOfBoundsException - if the lengths of the arrays are not the same (null is ok,
and/or size 0)
public static String replaceChars(String str,
char searchChar,
char replaceChar)
Replaces all occurrences of a character in a String with another.
This is a null-safe version of String.replace(char, char).
A null string input returns null.
An empty ("") string input returns an empty string.
StringUtils.replaceChars(null, *, *) = null
StringUtils.replaceChars("", *, *) = ""
StringUtils.replaceChars("abcba", 'b', 'y') = "aycya"
StringUtils.replaceChars("abcba", 'z', 'y') = "abcba"
str - String to replace characters in, may be nullsearchChar - the character to search for, may be nullreplaceChar - the character to replace, may be null
null if null string input
public static String replaceChars(String str,
String searchChars,
String replaceChars)
Replaces multiple characters in a String in one go. This method can also be used to delete characters.
For example:
replaceChars("hello", "ho", "jy") = jelly.
A null string input returns null.
An empty ("") string input returns an empty string.
A null or empty set of search characters returns the input string.
The length of the search characters should normally equal the length of the replace characters. If the search characters is longer, then the extra search characters are deleted. If the search characters is shorter, then the extra replace characters are ignored.
StringUtils.replaceChars(null, *, *) = null
StringUtils.replaceChars("", *, *) = ""
StringUtils.replaceChars("abc", null, *) = "abc"
StringUtils.replaceChars("abc", "", *) = "abc"
StringUtils.replaceChars("abc", "b", null) = "ac"
StringUtils.replaceChars("abc", "b", "") = "ac"
StringUtils.replaceChars("abcba", "bc", "yz") = "ayzya"
StringUtils.replaceChars("abcba", "bc", "y") = "ayya"
StringUtils.replaceChars("abcba", "bc", "yzx") = "ayzya"
str - String to replace characters in, may be nullsearchChars - a set of characters to search for, may be nullreplaceChars - a set of characters to replace, may be null
null if null string input
public static String overlay(String str,
String overlay,
int start,
int end)
Overlays part of a String with another String.
A null string input returns null.
A negative index is treated as zero.
An index greater than the string length is treated as the string length.
The start index is always the smaller of the two indices.
StringUtils.overlay(null, *, *, *) = null
StringUtils.overlay("", "abc", 0, 0) = "abc"
StringUtils.overlay("abcdef", null, 2, 4) = "abef"
StringUtils.overlay("abcdef", "", 2, 4) = "abef"
StringUtils.overlay("abcdef", "", 4, 2) = "abef"
StringUtils.overlay("abcdef", "zzzz", 2, 4) = "abzzzzef"
StringUtils.overlay("abcdef", "zzzz", 4, 2) = "abzzzzef"
StringUtils.overlay("abcdef", "zzzz", -1, 4) = "zzzzef"
StringUtils.overlay("abcdef", "zzzz", 2, 8) = "abzzzz"
StringUtils.overlay("abcdef", "zzzz", -2, -3) = "zzzzabcdef"
StringUtils.overlay("abcdef", "zzzz", 8, 10) = "abcdefzzzz"
str - the String to do overlaying in, may be nulloverlay - the String to overlay, may be nullstart - the position to start overlaying atend - the position to stop overlaying before
null if null String inputpublic static String chomp(String str)
Removes one newline from end of a String if it's there,
otherwise leave it alone. A newline is "\n",
"\r", or "\r\n".
NOTE: This method changed in 2.0. It now more closely matches Perl chomp.
StringUtils.chomp(null) = null
StringUtils.chomp("") = ""
StringUtils.chomp("abc \r") = "abc "
StringUtils.chomp("abc\n") = "abc"
StringUtils.chomp("abc\r\n") = "abc"
StringUtils.chomp("abc\r\n\r\n") = "abc\r\n"
StringUtils.chomp("abc\n\r") = "abc\n"
StringUtils.chomp("abc\n\rabc") = "abc\n\rabc"
StringUtils.chomp("\r") = ""
StringUtils.chomp("\n") = ""
StringUtils.chomp("\r\n") = ""
str - the String to chomp a newline from, may be null
null if null String input
public static String chomp(String str,
String separator)
Removes separator from the end of
str if it's there, otherwise leave it alone.
NOTE: This method changed in version 2.0.
It now more closely matches Perl chomp.
For the previous behavior, use substringBeforeLast(String, String).
This method uses String.endsWith(String).
StringUtils.chomp(null, *) = null
StringUtils.chomp("", *) = ""
StringUtils.chomp("foobar", "bar") = "foo"
StringUtils.chomp("foobar", "baz") = "foobar"
StringUtils.chomp("foo", "foo") = ""
StringUtils.chomp("foo ", "foo") = "foo "
StringUtils.chomp(" foo", "foo") = " "
StringUtils.chomp("foo", "foooo") = "foo"
StringUtils.chomp("foo", "") = "foo"
StringUtils.chomp("foo", null) = "foo"
str - the String to chomp from, may be nullseparator - separator String, may be null
null if null String inputpublic static String chop(String str)
Remove the last character from a String.
If the String ends in \r\n, then remove both
of them.
StringUtils.chop(null) = null
StringUtils.chop("") = ""
StringUtils.chop("abc \r") = "abc "
StringUtils.chop("abc\n") = "abc"
StringUtils.chop("abc\r\n") = "abc"
StringUtils.chop("abc") = "ab"
StringUtils.chop("abc\nabc") = "abc\nab"
StringUtils.chop("a") = ""
StringUtils.chop("\r") = ""
StringUtils.chop("\n") = ""
StringUtils.chop("\r\n") = ""
str - the String to chop last character from, may be null
null if null String input
public static String repeat(String str,
int repeat)
Repeat a String repeat times to form a
new String.
StringUtils.repeat(null, 2) = null
StringUtils.repeat("", 0) = ""
StringUtils.repeat("", 2) = ""
StringUtils.repeat("a", 3) = "aaa"
StringUtils.repeat("ab", 2) = "abab"
StringUtils.repeat("a", -2) = ""
str - the String to repeat, may be nullrepeat - number of times to repeat str, negative treated as zero
null if null String input
public static String repeat(String str,
String separator,
int repeat)
Repeat a String repeat times to form a
new String, with a String separator injected each time.
StringUtils.repeat(null, null, 2) = null
StringUtils.repeat(null, "x", 2) = null
StringUtils.repeat("", null, 0) = ""
StringUtils.repeat("", "", 2) = ""
StringUtils.repeat("", "x", 3) = "xxx"
StringUtils.repeat("?", ", ", 3) = "?, ?, ?"
str - the String to repeat, may be nullseparator - the String to inject, may be nullrepeat - number of times to repeat str, negative treated as zero
null if null String input
public static String rightPad(String str,
int size)
Right pad a String with spaces (' ').
The String is padded to the size of size.
StringUtils.rightPad(null, *) = null
StringUtils.rightPad("", 3) = " "
StringUtils.rightPad("bat", 3) = "bat"
StringUtils.rightPad("bat", 5) = "bat "
StringUtils.rightPad("bat", 1) = "bat"
StringUtils.rightPad("bat", -1) = "bat"
str - the String to pad out, may be nullsize - the size to pad to
null if null String input
public static String rightPad(String str,
int size,
char padChar)
Right pad a String with a specified character.
The String is padded to the size of size.
StringUtils.rightPad(null, *, *) = null
StringUtils.rightPad("", 3, 'z') = "zzz"
StringUtils.rightPad("bat", 3, 'z') = "bat"
StringUtils.rightPad("bat", 5, 'z') = "batzz"
StringUtils.rightPad("bat", 1, 'z') = "bat"
StringUtils.rightPad("bat", -1, 'z') = "bat"
str - the String to pad out, may be nullsize - the size to pad topadChar - the character to pad with
null if null String input
public static String rightPad(String str,
int size,
String padStr)
Right pad a String with a specified String.
The String is padded to the size of size.
StringUtils.rightPad(null, *, *) = null
StringUtils.rightPad("", 3, "z") = "zzz"
StringUtils.rightPad("bat", 3, "yz") = "bat"
StringUtils.rightPad("bat", 5, "yz") = "batyz"
StringUtils.rightPad("bat", 8, "yz") = "batyzyzy"
StringUtils.rightPad("bat", 1, "yz") = "bat"
StringUtils.rightPad("bat", -1, "yz") = "bat"
StringUtils.rightPad("bat", 5, null) = "bat "
StringUtils.rightPad("bat", 5, "") = "bat "
str - the String to pad out, may be nullsize - the size to pad topadStr - the String to pad with, null or empty treated as single space
null if null String input
public static String leftPad(String str,
int size)
Left pad a String with spaces (' ').
The String is padded to the size of size.
StringUtils.leftPad(null, *) = null
StringUtils.leftPad("", 3) = " "
StringUtils.leftPad("bat", 3) = "bat"
StringUtils.leftPad("bat", 5) = " bat"
StringUtils.leftPad("bat", 1) = "bat"
StringUtils.leftPad("bat", -1) = "bat"
str - the String to pad out, may be nullsize - the size to pad to
null if null String input
public static String leftPad(String str,
int size,
char padChar)
Left pad a String with a specified character.
Pad to a size of size.
StringUtils.leftPad(null, *, *) = null
StringUtils.leftPad("", 3, 'z') = "zzz"
StringUtils.leftPad("bat", 3, 'z') = "bat"
StringUtils.leftPad("bat", 5, 'z') = "zzbat"
StringUtils.leftPad("bat", 1, 'z') = "bat"
StringUtils.leftPad("bat", -1, 'z') = "bat"
str - the String to pad out, may be nullsize - the size to pad topadChar - the character to pad with
null if null String input
public static String leftPad(String str,
int size,
String padStr)
Left pad a String with a specified String.
Pad to a size of size.
StringUtils.leftPad(null, *, *) = null
StringUtils.leftPad("", 3, "z") = "zzz"
StringUtils.leftPad("bat", 3, "yz") = "bat"
StringUtils.leftPad("bat", 5, "yz") = "yzbat"
StringUtils.leftPad("bat", 8, "yz") = "yzyzybat"
StringUtils.leftPad("bat", 1, "yz") = "bat"
StringUtils.leftPad("bat", -1, "yz") = "bat"
StringUtils.leftPad("bat", 5, null) = " bat"
StringUtils.leftPad("bat", 5, "") = " bat"
str - the String to pad out, may be nullsize - the size to pad topadStr - the String to pad with, null or empty treated as single space
null if null String input@Deprecated public static int length(CharSequence cs)
CharSequenceUtils.length(CharSequence)
0 if the CharSequence is
null.
cs - a CharSequence or null
0 if the CharSequence is
null.
public static String center(String str,
int size)
Centers a String in a larger String of size size
using the space character (' ').
If the size is less than the String length, the String is returned.
A null String returns null.
A negative size is treated as zero.
Equivalent to center(str, size, " ").
StringUtils.center(null, *) = null
StringUtils.center("", 4) = " "
StringUtils.center("ab", -1) = "ab"
StringUtils.center("ab", 4) = " ab "
StringUtils.center("abcd", 2) = "abcd"
StringUtils.center("a", 4) = " a "
str - the String to center, may be nullsize - the int size of new String, negative treated as zero
null if null String input
public static String center(String str,
int size,
char padChar)
Centers a String in a larger String of size size.
Uses a supplied character as the value to pad the String with.
If the size is less than the String length, the String is returned.
A null String returns null.
A negative size is treated as zero.
StringUtils.center(null, *, *) = null
StringUtils.center("", 4, ' ') = " "
StringUtils.center("ab", -1, ' ') = "ab"
StringUtils.center("ab", 4, ' ') = " ab"
StringUtils.center("abcd", 2, ' ') = "abcd"
StringUtils.center("a", 4, ' ') = " a "
StringUtils.center("a", 4, 'y') = "yayy"
str - the String to center, may be nullsize - the int size of new String, negative treated as zeropadChar - the character to pad the new String with
null if null String input
public static String center(String str,
int size,
String padStr)
Centers a String in a larger String of size size.
Uses a supplied String as the value to pad the String with.
If the size is less than the String length, the String is returned.
A null String returns null.
A negative size is treated as zero.
StringUtils.center(null, *, *) = null
StringUtils.center("", 4, " ") = " "
StringUtils.center("ab", -1, " ") = "ab"
StringUtils.center("ab", 4, " ") = " ab"
StringUtils.center("abcd", 2, " ") = "abcd"
StringUtils.center("a", 4, " ") = " a "
StringUtils.center("a", 4, "yz") = "yayz"
StringUtils.center("abc", 7, null) = " abc "
StringUtils.center("abc", 7, "") = " abc "
str - the String to center, may be nullsize - the int size of new String, negative treated as zeropadStr - the String to pad the new String with, must not be null or empty
null if null String input
IllegalArgumentException - if padStr is null or emptypublic static String upperCase(String str)
Converts a String to upper case as per String.toUpperCase().
A null input String returns null.
StringUtils.upperCase(null) = null
StringUtils.upperCase("") = ""
StringUtils.upperCase("aBc") = "ABC"
Note: As described in the documentation for String.toUpperCase(),
the result of this method is affected by the current locale.
For platform-independent case transformations, the method lowerCase(String, Locale)
should be used with a specific locale (e.g. Locale.ENGLISH).
str - the String to upper case, may be null
null if null String input
public static String upperCase(String str,
Locale locale)
Converts a String to upper case as per String.toUpperCase(Locale).
A null input String returns null.
StringUtils.upperCase(null, Locale.ENGLISH) = null
StringUtils.upperCase("", Locale.ENGLISH) = ""
StringUtils.upperCase("aBc", Locale.ENGLISH) = "ABC"
str - the String to upper case, may be nulllocale - the locale that defines the case transformation rules, must not be null
null if null String inputpublic static String lowerCase(String str)
Converts a String to lower case as per String.toLowerCase().
A null input String returns null.
StringUtils.lowerCase(null) = null
StringUtils.lowerCase("") = ""
StringUtils.lowerCase("aBc") = "abc"
Note: As described in the documentation for String.toLowerCase(),
the result of this method is affected by the current locale.
For platform-independent case transformations, the method lowerCase(String, Locale)
should be used with a specific locale (e.g. Locale.ENGLISH).
str - the String to lower case, may be null
null if null String input
public static String lowerCase(String str,
Locale locale)
Converts a String to lower case as per String.toLowerCase(Locale).
A null input String returns null.
StringUtils.lowerCase(null, Locale.ENGLISH) = null
StringUtils.lowerCase("", Locale.ENGLISH) = ""
StringUtils.lowerCase("aBc", Locale.ENGLISH) = "abc"
str - the String to lower case, may be nulllocale - the locale that defines the case transformation rules, must not be null
null if null String inputpublic static String capitalize(CharSequence cs)
Capitalizes a String changing the first letter to title case as
per Character.toTitleCase(char). No other letters are changed.
For a word based algorithm, see WordUtils.capitalize(String).
A null input String returns null.
StringUtils.capitalize(null) = null
StringUtils.capitalize("") = ""
StringUtils.capitalize("cat") = "Cat"
StringUtils.capitalize("cAt") = "CAt"
cs - the String to capitalize, may be null
null if null String inputWordUtils.capitalize(String),
uncapitalize(CharSequence)public static String uncapitalize(CharSequence cs)
Uncapitalizes a CharSequence changing the first letter to title case as
per Character.toLowerCase(char). No other letters are changed.
For a word based algorithm, see WordUtils.uncapitalize(String).
A null input String returns null.
StringUtils.uncapitalize(null) = null
StringUtils.uncapitalize("") = ""
StringUtils.uncapitalize("Cat") = "cat"
StringUtils.uncapitalize("CAT") = "cAT"
cs - the String to uncapitalize, may be null
null if null String inputWordUtils.uncapitalize(String),
capitalize(CharSequence)public static String swapCase(String str)
Swaps the case of a String changing upper and title case to lower case, and lower case to upper case.
For a word based algorithm, see WordUtils.swapCase(String).
A null input String returns null.
StringUtils.swapCase(null) = null
StringUtils.swapCase("") = ""
StringUtils.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"
NOTE: This method changed in Lang version 2.0. It no longer performs a word based algorithm. If you only use ASCII, you will notice no change. That functionality is available in org.apache.commons.lang3.text.WordUtils.
str - the String to swap case, may be null
null if null String input
public static int countMatches(String str,
String sub)
Counts how many times the substring appears in the larger String.
A null or empty ("") String input returns 0.
StringUtils.countMatches(null, *) = 0
StringUtils.countMatches("", *) = 0
StringUtils.countMatches("abba", null) = 0
StringUtils.countMatches("abba", "") = 0
StringUtils.countMatches("abba", "a") = 2
StringUtils.countMatches("abba", "ab") = 1
StringUtils.countMatches("abba", "xxx") = 0
str - the String to check, may be nullsub - the substring to count, may be null
nullpublic static boolean isAlpha(CharSequence cs)
Checks if the CharSequence contains only unicode letters.
null will return false.
An empty CharSequence (length()=0) will return true.
StringUtils.isAlpha(null) = false
StringUtils.isAlpha("") = true
StringUtils.isAlpha(" ") = false
StringUtils.isAlpha("abc") = true
StringUtils.isAlpha("ab2c") = false
StringUtils.isAlpha("ab-c") = false
cs - the CharSequence to check, may be null
true if only contains letters, and is non-nullpublic static boolean isAlphaSpace(CharSequence cs)
Checks if the CharSequence contains only unicode letters and space (' ').
null will return false
An empty CharSequence (length()=0) will return true.
StringUtils.isAlphaSpace(null) = false
StringUtils.isAlphaSpace("") = true
StringUtils.isAlphaSpace(" ") = true
StringUtils.isAlphaSpace("abc") = true
StringUtils.isAlphaSpace("ab c") = true
StringUtils.isAlphaSpace("ab2c") = false
StringUtils.isAlphaSpace("ab-c") = false
cs - the CharSequence to check, may be null
true if only contains letters and space,
and is non-nullpublic static boolean isAlphanumeric(CharSequence cs)
Checks if the CharSequence contains only unicode letters or digits.
null will return false.
An empty CharSequence (length()=0) will return true.
StringUtils.isAlphanumeric(null) = false
StringUtils.isAlphanumeric("") = true
StringUtils.isAlphanumeric(" ") = false
StringUtils.isAlphanumeric("abc") = true
StringUtils.isAlphanumeric("ab c") = false
StringUtils.isAlphanumeric("ab2c") = true
StringUtils.isAlphanumeric("ab-c") = false
cs - the CharSequence to check, may be null
true if only contains letters or digits,
and is non-nullpublic static boolean isAlphanumericSpace(CharSequence cs)
Checks if the CharSequence contains only unicode letters, digits
or space (' ').
null will return false.
An empty CharSequence (length()=0) will return true.
StringUtils.isAlphanumeric(null) = false
StringUtils.isAlphanumeric("") = true
StringUtils.isAlphanumeric(" ") = true
StringUtils.isAlphanumeric("abc") = true
StringUtils.isAlphanumeric("ab c") = true
StringUtils.isAlphanumeric("ab2c") = true
StringUtils.isAlphanumeric("ab-c") = false
cs - the CharSequence to check, may be null
true if only contains letters, digits or space,
and is non-nullpublic static boolean isAsciiPrintable(CharSequence cs)
Checks if the CharSequence contains only ASCII printable characters.
null will return false.
An empty CharSequence (length()=0) will return true.
StringUtils.isAsciiPrintable(null) = false
StringUtils.isAsciiPrintable("") = true
StringUtils.isAsciiPrintable(" ") = true
StringUtils.isAsciiPrintable("Ceki") = true
StringUtils.isAsciiPrintable("ab2c") = true
StringUtils.isAsciiPrintable("!ab-c~") = true
StringUtils.isAsciiPrintable(" ") = true
StringUtils.isAsciiPrintable("!") = true
StringUtils.isAsciiPrintable("~") = true
StringUtils.isAsciiPrintable("") = false
StringUtils.isAsciiPrintable("Ceki Gülcü") = false
cs - the CharSequence to check, may be null
true if every character is in the range
32 thru 126public static boolean isNumeric(CharSequence cs)
Checks if the CharSequence contains only unicode digits. A decimal point is not a unicode digit and returns false.
null will return false.
An empty CharSequence (length()=0) will return true.
StringUtils.isNumeric(null) = false
StringUtils.isNumeric("") = true
StringUtils.isNumeric(" ") = false
StringUtils.isNumeric("123") = true
StringUtils.isNumeric("12 3") = false
StringUtils.isNumeric("ab2c") = false
StringUtils.isNumeric("12-3") = false
StringUtils.isNumeric("12.3") = false
cs - the CharSequence to check, may be null
true if only contains digits, and is non-nullpublic static boolean isNumericSpace(CharSequence cs)
Checks if the CharSequence contains only unicode digits or space
(' ').
A decimal point is not a unicode digit and returns false.
null will return false.
An empty CharSequence (length()=0) will return true.
StringUtils.isNumeric(null) = false
StringUtils.isNumeric("") = true
StringUtils.isNumeric(" ") = true
StringUtils.isNumeric("123") = true
StringUtils.isNumeric("12 3") = true
StringUtils.isNumeric("ab2c") = false
StringUtils.isNumeric("12-3") = false
StringUtils.isNumeric("12.3") = false
cs - the CharSequence to check, may be null
true if only contains digits or space,
and is non-nullpublic static boolean isWhitespace(CharSequence cs)
Checks if the CharSequence contains only whitespace.
null will return false.
An empty CharSequence (length()=0) will return true.
StringUtils.isWhitespace(null) = false
StringUtils.isWhitespace("") = true
StringUtils.isWhitespace(" ") = true
StringUtils.isWhitespace("abc") = false
StringUtils.isWhitespace("ab2c") = false
StringUtils.isWhitespace("ab-c") = false
cs - the CharSequence to check, may be null
true if only contains whitespace, and is non-nullpublic static boolean isAllLowerCase(CharSequence cs)
Checks if the CharSequence contains only lowercase characters.
null will return false.
An empty CharSequence (length()=0) will return false.
StringUtils.isAllLowerCase(null) = false
StringUtils.isAllLowerCase("") = false
StringUtils.isAllLowerCase(" ") = false
StringUtils.isAllLowerCase("abc") = true
StringUtils.isAllLowerCase("abC") = false
cs - the CharSequence to check, may be null
true if only contains lowercase characters, and is non-nullpublic static boolean isAllUpperCase(CharSequence cs)
Checks if the CharSequence contains only uppercase characters.
null will return false.
An empty String (length()=0) will return false.
StringUtils.isAllUpperCase(null) = false
StringUtils.isAllUpperCase("") = false
StringUtils.isAllUpperCase(" ") = false
StringUtils.isAllUpperCase("ABC") = true
StringUtils.isAllUpperCase("aBC") = false
cs - the CharSequence to check, may be null
true if only contains uppercase characters, and is non-nullpublic static String defaultString(String str)
Returns either the passed in String,
or if the String is null, an empty String ("").
StringUtils.defaultString(null) = ""
StringUtils.defaultString("") = ""
StringUtils.defaultString("bat") = "bat"
str - the String to check, may be null
nullObjectUtils.toString(Object),
String.valueOf(Object)
public static String defaultString(String str,
String defaultStr)
Returns either the passed in String, or if the String is
null, the value of defaultStr.
StringUtils.defaultString(null, "NULL") = "NULL"
StringUtils.defaultString("", "NULL") = ""
StringUtils.defaultString("bat", "NULL") = "bat"
str - the String to check, may be nulldefaultStr - the default String to return
if the input is null, may be null
nullObjectUtils.toString(Object,String),
String.valueOf(Object)
public static <T extends CharSequence> T defaultIfEmpty(T str,
T defaultStr)
Returns either the passed in CharSequence, or if the CharSequence is
empty or null, the value of defaultStr.
StringUtils.defaultIfEmpty(null, "NULL") = "NULL"
StringUtils.defaultIfEmpty("", "NULL") = "NULL"
StringUtils.defaultIfEmpty("bat", "NULL") = "bat"
StringUtils.defaultIfEmpty("", null) = null
T - the specific kind of CharSequencestr - the CharSequence to check, may be nulldefaultStr - the default CharSequence to return
if the input is empty ("") or null, may be null
defaultString(String, String)public static String reverse(String str)
Reverses a String as per StringBuilder.reverse().
A null String returns null.
StringUtils.reverse(null) = null
StringUtils.reverse("") = ""
StringUtils.reverse("bat") = "tab"
str - the String to reverse, may be null
null if null String input
public static String reverseDelimited(String str,
char separatorChar)
Reverses a String that is delimited by a specific character.
The Strings between the delimiters are not reversed.
Thus java.lang.String becomes String.lang.java (if the delimiter
is '.').
StringUtils.reverseDelimited(null, *) = null
StringUtils.reverseDelimited("", *) = ""
StringUtils.reverseDelimited("a.b.c", 'x') = "a.b.c"
StringUtils.reverseDelimited("a.b.c", ".") = "c.b.a"
str - the String to reverse, may be nullseparatorChar - the separator character to use
null if null String input
public static String abbreviate(String str,
int maxWidth)
Abbreviates a String using ellipses. This will turn "Now is the time for all good men" into "Now is the time for..."
Specifically:
str is less than maxWidth characters
long, return it.(substring(str, 0, max-3) + "...").maxWidth is less than 4, throw an
IllegalArgumentException.maxWidth.
StringUtils.abbreviate(null, *) = null
StringUtils.abbreviate("", 4) = ""
StringUtils.abbreviate("abcdefg", 6) = "abc..."
StringUtils.abbreviate("abcdefg", 7) = "abcdefg"
StringUtils.abbreviate("abcdefg", 8) = "abcdefg"
StringUtils.abbreviate("abcdefg", 4) = "a..."
StringUtils.abbreviate("abcdefg", 3) = IllegalArgumentException
str - the String to check, may be nullmaxWidth - maximum length of result String, must be at least 4
null if null String input
IllegalArgumentException - if the width is too small
public static String abbreviate(String str,
int offset,
int maxWidth)
Abbreviates a String using ellipses. This will turn "Now is the time for all good men" into "...is the time for..."
Works like abbreviate(String, int), but allows you to specify
a "left edge" offset. Note that this left edge is not necessarily going to
be the leftmost character in the result, or the first character following the
ellipses, but it will appear somewhere in the result.
In no case will it return a String of length greater than
maxWidth.
StringUtils.abbreviate(null, *, *) = null
StringUtils.abbreviate("", 0, 4) = ""
StringUtils.abbreviate("abcdefghijklmno", -1, 10) = "abcdefg..."
StringUtils.abbreviate("abcdefghijklmno", 0, 10) = "abcdefg..."
StringUtils.abbreviate("abcdefghijklmno", 1, 10) = "abcdefg..."
StringUtils.abbreviate("abcdefghijklmno", 4, 10) = "abcdefg..."
StringUtils.abbreviate("abcdefghijklmno", 5, 10) = "...fghi..."
StringUtils.abbreviate("abcdefghijklmno", 6, 10) = "...ghij..."
StringUtils.abbreviate("abcdefghijklmno", 8, 10) = "...ijklmno"
StringUtils.abbreviate("abcdefghijklmno", 10, 10) = "...ijklmno"
StringUtils.abbreviate("abcdefghijklmno", 12, 10) = "...ijklmno"
StringUtils.abbreviate("abcdefghij", 0, 3) = IllegalArgumentException
StringUtils.abbreviate("abcdefghij", 5, 6) = IllegalArgumentException
str - the String to check, may be nulloffset - left edge of source StringmaxWidth - maximum length of result String, must be at least 4
null if null String input
IllegalArgumentException - if the width is too small
public static String abbreviateMiddle(String str,
String middle,
int length)
Abbreviates a String to the length passed, replacing the middle characters with the supplied replacement String.
This abbreviation only occurs if the following criteria is met:
StringUtils.abbreviateMiddle(null, null, 0) = null
StringUtils.abbreviateMiddle("abc", null, 0) = "abc"
StringUtils.abbreviateMiddle("abc", ".", 0) = "abc"
StringUtils.abbreviateMiddle("abc", ".", 3) = "abc"
StringUtils.abbreviateMiddle("abcdef", ".", 4) = "ab.f"
str - the String to abbreviate, may be nullmiddle - the String to replace the middle characters with, may be nulllength - the length to abbreviate str to.
public static String difference(String str1,
String str2)
Compares two Strings, and returns the portion where they differ. (More precisely, return the remainder of the second String, starting from where it's different from the first.)
For example,
difference("i am a machine", "i am a robot") -> "robot".
StringUtils.difference(null, null) = null
StringUtils.difference("", "") = ""
StringUtils.difference("", "abc") = "abc"
StringUtils.difference("abc", "") = ""
StringUtils.difference("abc", "abc") = ""
StringUtils.difference("ab", "abxyz") = "xyz"
StringUtils.difference("abcde", "abxyz") = "xyz"
StringUtils.difference("abcde", "xyz") = "xyz"
str1 - the first String, may be nullstr2 - the second String, may be null
public static int indexOfDifference(CharSequence cs1,
CharSequence cs2)
Compares two CharSequences, and returns the index at which the CharSequences begin to differ.
For example,
indexOfDifference("i am a machine", "i am a robot") -> 7
StringUtils.indexOfDifference(null, null) = -1
StringUtils.indexOfDifference("", "") = -1
StringUtils.indexOfDifference("", "abc") = 0
StringUtils.indexOfDifference("abc", "") = 0
StringUtils.indexOfDifference("abc", "abc") = -1
StringUtils.indexOfDifference("ab", "abxyz") = 2
StringUtils.indexOfDifference("abcde", "abxyz") = 2
StringUtils.indexOfDifference("abcde", "xyz") = 0
cs1 - the first CharSequence, may be nullcs2 - the second CharSequence, may be null
public static int indexOfDifference(CharSequence... css)
Compares all CharSequences in an array and returns the index at which the CharSequences begin to differ.
For example,
indexOfDifference(new String[] {"i am a machine", "i am a robot"}) -> 7
StringUtils.indexOfDifference(null) = -1
StringUtils.indexOfDifference(new String[] {}) = -1
StringUtils.indexOfDifference(new String[] {"abc"}) = -1
StringUtils.indexOfDifference(new String[] {null, null}) = -1
StringUtils.indexOfDifference(new String[] {"", ""}) = -1
StringUtils.indexOfDifference(new String[] {"", null}) = 0
StringUtils.indexOfDifference(new String[] {"abc", null, null}) = 0
StringUtils.indexOfDifference(new String[] {null, null, "abc"}) = 0
StringUtils.indexOfDifference(new String[] {"", "abc"}) = 0
StringUtils.indexOfDifference(new String[] {"abc", ""}) = 0
StringUtils.indexOfDifference(new String[] {"abc", "abc"}) = -1
StringUtils.indexOfDifference(new String[] {"abc", "a"}) = 1
StringUtils.indexOfDifference(new String[] {"ab", "abxyz"}) = 2
StringUtils.indexOfDifference(new String[] {"abcde", "abxyz"}) = 2
StringUtils.indexOfDifference(new String[] {"abcde", "xyz"}) = 0
StringUtils.indexOfDifference(new String[] {"xyz", "abcde"}) = 0
StringUtils.indexOfDifference(new String[] {"i am a machine", "i am a robot"}) = 7
css - array of CharSequences, entries may be null
public static String getCommonPrefix(String... strs)
Compares all Strings in an array and returns the initial sequence of characters that is common to all of them.
For example,
getCommonPrefix(new String[] {"i am a machine", "i am a robot"}) -> "i am a "
StringUtils.getCommonPrefix(null) = ""
StringUtils.getCommonPrefix(new String[] {}) = ""
StringUtils.getCommonPrefix(new String[] {"abc"}) = "abc"
StringUtils.getCommonPrefix(new String[] {null, null}) = ""
StringUtils.getCommonPrefix(new String[] {"", ""}) = ""
StringUtils.getCommonPrefix(new String[] {"", null}) = ""
StringUtils.getCommonPrefix(new String[] {"abc", null, null}) = ""
StringUtils.getCommonPrefix(new String[] {null, null, "abc"}) = ""
StringUtils.getCommonPrefix(new String[] {"", "abc"}) = ""
StringUtils.getCommonPrefix(new String[] {"abc", ""}) = ""
StringUtils.getCommonPrefix(new String[] {"abc", "abc"}) = "abc"
StringUtils.getCommonPrefix(new String[] {"abc", "a"}) = "a"
StringUtils.getCommonPrefix(new String[] {"ab", "abxyz"}) = "ab"
StringUtils.getCommonPrefix(new String[] {"abcde", "abxyz"}) = "ab"
StringUtils.getCommonPrefix(new String[] {"abcde", "xyz"}) = ""
StringUtils.getCommonPrefix(new String[] {"xyz", "abcde"}) = ""
StringUtils.getCommonPrefix(new String[] {"i am a machine", "i am a robot"}) = "i am a "
strs - array of String objects, entries may be null
public static int getLevenshteinDistance(CharSequence s,
CharSequence t)
Find the Levenshtein distance between two Strings.
This is the number of changes needed to change one String into another, where each change is a single character modification (deletion, insertion or substitution).
The previous implementation of the Levenshtein distance algorithm was from http://www.merriampark.com/ld.htm
Chas Emerick has written an implementation in Java, which avoids an OutOfMemoryError
which can occur when my Java implementation is used with very large strings.
This implementation of the Levenshtein distance algorithm
is from http://www.merriampark.com/ldjava.htm
StringUtils.getLevenshteinDistance(null, *) = IllegalArgumentException
StringUtils.getLevenshteinDistance(*, null) = IllegalArgumentException
StringUtils.getLevenshteinDistance("","") = 0
StringUtils.getLevenshteinDistance("","a") = 1
StringUtils.getLevenshteinDistance("aaapppp", "") = 7
StringUtils.getLevenshteinDistance("frog", "fog") = 1
StringUtils.getLevenshteinDistance("fly", "ant") = 3
StringUtils.getLevenshteinDistance("elephant", "hippo") = 7
StringUtils.getLevenshteinDistance("hippo", "elephant") = 7
StringUtils.getLevenshteinDistance("hippo", "zzzzzzzz") = 8
StringUtils.getLevenshteinDistance("hello", "hallo") = 1
s - the first String, must not be nullt - the second String, must not be null
IllegalArgumentException - if either String input null
public static boolean startsWith(String str,
String prefix)
Check if a String starts with a specified prefix.
nulls are handled without exceptions. Two null
references are considered to be equal. The comparison is case sensitive.
StringUtils.startsWith(null, null) = true
StringUtils.startsWith(null, "abc") = false
StringUtils.startsWith("abcdef", null) = false
StringUtils.startsWith("abcdef", "abc") = true
StringUtils.startsWith("ABCDEF", "abc") = false
str - the String to check, may be nullprefix - the prefix to find, may be null
true if the String starts with the prefix, case sensitive, or
both nullString.startsWith(String)
public static boolean startsWithIgnoreCase(String str,
String prefix)
Case insensitive check if a String starts with a specified prefix.
nulls are handled without exceptions. Two null
references are considered to be equal. The comparison is case insensitive.
StringUtils.startsWithIgnoreCase(null, null) = true
StringUtils.startsWithIgnoreCase(null, "abc") = false
StringUtils.startsWithIgnoreCase("abcdef", null) = false
StringUtils.startsWithIgnoreCase("abcdef", "abc") = true
StringUtils.startsWithIgnoreCase("ABCDEF", "abc") = true
str - the String to check, may be nullprefix - the prefix to find, may be null
true if the String starts with the prefix, case insensitive, or
both nullString.startsWith(String)
public static boolean startsWithAny(String string,
String... searchStrings)
Check if a String starts with any of an array of specified strings.
StringUtils.startsWithAny(null, null) = false
StringUtils.startsWithAny(null, new String[] {"abc"}) = false
StringUtils.startsWithAny("abcxyz", null) = false
StringUtils.startsWithAny("abcxyz", new String[] {""}) = false
StringUtils.startsWithAny("abcxyz", new String[] {"abc"}) = true
StringUtils.startsWithAny("abcxyz", new String[] {null, "xyz", "abc"}) = true
string - the String to check, may be nullsearchStrings - the Strings to find, may be null or empty
true if the String starts with any of the the prefixes, case insensitive, or
both null
public static boolean endsWith(String str,
String suffix)
Check if a String ends with a specified suffix.
nulls are handled without exceptions. Two null
references are considered to be equal. The comparison is case sensitive.
StringUtils.endsWith(null, null) = true
StringUtils.endsWith(null, "def") = false
StringUtils.endsWith("abcdef", null) = false
StringUtils.endsWith("abcdef", "def") = true
StringUtils.endsWith("ABCDEF", "def") = false
StringUtils.endsWith("ABCDEF", "cde") = false
str - the String to check, may be nullsuffix - the suffix to find, may be null
true if the String ends with the suffix, case sensitive, or
both nullString.endsWith(String)
public static boolean endsWithIgnoreCase(String str,
String suffix)
Case insensitive check if a String ends with a specified suffix.
nulls are handled without exceptions. Two null
references are considered to be equal. The comparison is case insensitive.
StringUtils.endsWithIgnoreCase(null, null) = true
StringUtils.endsWithIgnoreCase(null, "def") = false
StringUtils.endsWithIgnoreCase("abcdef", null) = false
StringUtils.endsWithIgnoreCase("abcdef", "def") = true
StringUtils.endsWithIgnoreCase("ABCDEF", "def") = true
StringUtils.endsWithIgnoreCase("ABCDEF", "cde") = false
str - the String to check, may be nullsuffix - the suffix to find, may be null
true if the String ends with the suffix, case insensitive, or
both nullString.endsWith(String)
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