StringUtils (sorm-码云(gitee.com))

java.lang.Object
- sf.tools.StringUtils

```
public class StringUtils
extends Object
```
模仿common-lang中的代码.

Constructor Summary

Constructors
Constructor and Description

StringUtils()

Constructors
Constructor and Description
`StringUtils()`

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static String`	`center(String str, int size)`
`static String`	`center(String str, int size, char padChar)`
`static boolean`	`contains(CharSequence seq, CharSequence searchSeq)` Checks if CharSequence contains a search CharSequence, handling `null`.
`static boolean`	`contains(CharSequence seq, int searchChar)` Checks if CharSequence contains a search character, handling `null`.
`static boolean`	`containsIgnoreCase(CharSequence str, CharSequence searchStr)` Checks if CharSequence contains a search CharSequence irrespective of case, handling `null`.
`static int`	`count(String source, char c)`
`static int`	`count(String source, char c, int start)`
`static int`	`count(String source, String substr)`
`static int`	`count(String source, String substr, int start)`
`static String`	`defaultIfBlank(String s, String defaultStr)` Returns either the passed in String, or if the String is whitespace, empty ("") or `null`, the value of `defaultStr`.
`static String`	`defaultIfEmpty(String s, String defaultStr)` Returns either the passed in String, or if the String is empty or `null`, the value of `defaultStr`.
`static String`	`defaultIfNull(String s, String defaultStr)` Returns either the passed in String, or if the String is `null`, the value of `defaultStr`.
`static String`	`deleteWhitespace(String s)` Deletes all whitespaces from a String as defined by `Character.isWhitespace(char)`.
`static boolean`	`endsWith(String s, String suffix)` Check if a String ends with a specified suffix.
`static boolean`	`endsWithChar(String s, char c)`
`static boolean`	`endsWithIgnoreCase(String s, String suffix)` Case insensitive check if a String ends with a specified suffix.
`static int`	`endsWithOne(String src, String... dest)`
`static int`	`endsWithOneIgnoreCase(String s, String... dest)`
`static boolean`	`equals(String s1, String s2)` Compares two CharSequences, returning `true` if they represent equal sequences of characters.
`static boolean`	`equalsIgnoreCase(String s1, String s2)` Compares two CharSequences, returning `true` if they represent equal sequences of characters, ignoring case.
`static String`	`firstCharToLowerCase(String str)` 首字母变小写
`static String`	`firstCharToUpperCase(String str)` 首字母变大写
`static byte[]`	`getBytes(String s, String charsetName)`
`static String`	`getCRC(InputStream in)` 计算CRC摘要,8位十六进制数
`static String`	`getCRC(String s)` 计算CRC摘要,8位十六进制数
`static byte[]`	`getUtf8Bytes(String s)`
`static int[]`	`indexOf(String s, char[] c)` Finds the very first index of a substring from the specified array.
`static int[]`	`indexOf(String s, char[] c, int start)` Finds the very first index of a char from the specified array.
`static int`	`indexOf(String s, char c, int startIndex, int endIndex)` Finds the first occurrence of a character in the given source but within limited range (start, end].
`static int[]`	`indexOf(String s, String[] arr)` Finds the very first index of a substring from the specified array.
`static int[]`	`indexOf(String s, String[] arr, int start)` Finds the very first index of a substring from the specified array.
`static int`	`indexOf(String s, String substr, int startIndex, int endIndex)` Finds first occurrence of a substring in the given source but within limited range [start, end).
`static int`	`indexOfIgnoreCase(String s, char c, int startIndex, int endIndex)` Finds the first occurrence of a character in the given source but within limited range (start, end].
`static int`	`indexOfIgnoreCase(String s, String substr)` Finds first index of a substring in the given source string with ignored case.
`static int[]`	`indexOfIgnoreCase(String s, String[] arr)` Finds the very first index of a substring from the specified array.
`static int[]`	`indexOfIgnoreCase(String s, String[] arr, int start)` Finds the very first index of a substring from the specified array.
`static int`	`indexOfIgnoreCase(String s, String substr, int startIndex)` Finds first index of a substring in the given source string with ignored case.
`static int`	`indexOfIgnoreCase(String s, String substr, int startIndex, int endIndex)` Finds first index of a substring in the given source string and range with ignored case.
`static boolean`	`isBlank(String s)` Checks if a String is whitespace, empty ("") or null.
`static boolean`	`isEmpty(CharSequence cs)`
`static boolean`	`isEmpty(String s)` Checks if a String is empty ("") or null.
`static boolean`	`isNotBlank(String s)` Checks if a String is not empty (""), not null and not whitespace only.
`static boolean`	`isNotEmpty(String s)` Checks if a String is not empty ("") and not null.
`static String`	`join(Iterable<?> elements, String separator)`
`static String`	`join(Iterator<?> elements, String separator)`
`static String`	`join(Object[] elements, String separator)`
`static String`	`join(String... parts)`
`static String`	`join(String[] stringArray, String separator)`
`static int[]`	`lastIndexOf(String s, char[] c)` Finds the very last index of a substring from the specified array.
`static int[]`	`lastIndexOf(String s, char[] c, int fromIndex)` Finds the very last index of a substring from the specified array.
`static int`	`lastIndexOf(String s, char c, int startIndex, int endIndex)` Finds last index of a character in the given source string in specified range [end, start]
`static int[]`	`lastIndexOf(String s, String[] arr)` Finds the very last index of a substring from the specified array.
`static int[]`	`lastIndexOf(String s, String[] arr, int fromIndex)` Finds the very last index of a substring from the specified array.
`static int`	`lastIndexOf(String s, String sub, int startIndex, int endIndex)` Finds last index of a substring in the given source string in specified range [end, start] See `indexOf(String, String, int, int)` for details about the speed.
`static int`	`lastIndexOfIgnoreCase(String s, char c, int startIndex, int endIndex)` Finds last index of a character in the given source string in specified range [end, start]
`static int`	`lastIndexOfIgnoreCase(String s, String substr)` Finds last index of a substring in the given source string with ignored case.
`static int[]`	`lastIndexOfIgnoreCase(String s, String[] arr)` Finds the very last index of a substring from the specified array.
`static int[]`	`lastIndexOfIgnoreCase(String s, String[] arr, int fromIndex)` Finds the very last index of a substring from the specified array.
`static int`	`lastIndexOfIgnoreCase(String s, String substr, int startIndex)` Finds last index of a substring in the given source string with ignored case.
`static int`	`lastIndexOfIgnoreCase(String s, String sub, int startIndex, int endIndex)` Finds last index of a substring in the given source string with ignored case in specified range.
`static String`	`left(String s, int len)` Gets the leftmost `len` characters of a String.
`static String`	`leftPad(String str, int size)`
`static String`	`leftPad(String str, int size, char padChar)`
`static String`	`leftPad(String str, int size, String padStr)`
`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 s, int pos, int len)` Gets `len` characters from the middle of a String.
`static String`	`prefix(String s, String prefix)`
`static String`	`randomString()` 产生8位的随机数字
`static String`	`remove(String s, char remove)` Removes all occurrences of a character from within the source string.
`static String`	`remove(String s, String remove)` Removes all occurrences of a substring from within the source string.
`static String`	`removeChars(String s, char... chars)` Removes set of characters from string.
`static String`	`removeChars(String s, String chars)` Removes all characters contained in provided string.
`static String`	`removeEnd(String s, 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 s, 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 s, String remove)` Removes a substring only if it is at the beginning of a source string, otherwise returns the source string.
`static String`	`removeStartIgnoreCase(String s, String remove)` Case insensitive removal of a substring if it is at the beginning of a source string, otherwise returns the source string.
`static String`	`repeat(char ch, int repeat)` Returns padding using the specified delimiter repeated to a given length.
`static String`	`repeat(String s, int repeat)` Repeat a String `repeat` times to form a new String.
`static String`	`repeat(String s, 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`	`replacePattern(String source, String regex, String replacement)` Replaces each substring of the source String that matches the given regular expression with the given replacement using the `Pattern.DOTALL` option.
`static String`	`reverse(String s)`
`static String`	`right(String s, int len)` Gets the rightmost `len` characters of a String.
`static String`	`rightPad(String str, int size)`
`static String`	`rightPad(String str, int size, char padChar)`
`static String`	`rightPad(String str, int size, String padStr)`
`static String[]`	`split(String str, char delimiter)`
`static String[]`	`split(String str, String delimiter)`
`static String[]`	`splitChars(String str, char... delimiters)`
`static String[]`	`splitChars(String str, String delimiters)`
`static String[]`	`splitCSV(String str)` 按逗号分隔，两边加引号的不分割（CSV 规则）.
`static boolean`	`startsWith(String s, String prefix)` Check if a String starts with a specified prefix.
`static boolean`	`startsWithChar(String s, char c)`
`static boolean`	`startsWithIgnoreCase(String s, String prefix)` Case insensitive check if a String starts with a specified prefix.
`static int`	`startsWithOne(String s, String... dest)`
`static int`	`startsWithOneIgnoreCase(String s, String... dest)`
`static String`	`substring(String s, int start)` Gets a substring from the specified String avoiding exceptions.
`static String`	`substring(String s, int start, int end)` Gets a substring from the specified String avoiding exceptions.
`static String`	`substringAfter(String s, String separator)` Gets the substring after the first occurrence of a separator.
`static String`	`substringAfterLast(String s, String separator)` Gets the substring after the last occurrence of a separator.
`static String`	`substringAfterLastIfExist(String source, String keyword)` 返回字串，如果查找的字串不存在则返回全部和substringAfterLast方法不同，substringAfterLast方法在查找不到时返回空串
`static String`	`substringBefore(String s, String separator)` Gets the substring before the first occurrence of a separator.
`static String`	`substringBeforeLast(String s, String separator)` Gets the substring before the last occurrence of a separator.
`static String`	`substringBetween(String s, String tag)` Gets the String that is nested in between two instances of the same String.
`static String`	`substringBetween(String s, String open, String close)` Gets the String that is nested in between two Strings.
`static String`	`suffix(String s, String suffix)`
`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`	`toCamelCase(String stringWithUnderline)`
`static String`	`trim(String s)` Removes control characters (char <= 32) from both ends of this String, handling `null` by returning `null`.
`static String[]`	`trim(String[] ss)`
`static String`	`trimToEmpty(String s)` 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 s)` 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`	`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)`.
`static String`	`uuid32()` 返回32位uuid
`static String`	`uuid36()` 返回36位uuid

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail
- StringUtils
```
public StringUtils()
```

Method Detail

uuid32
```
public static String uuid32()
```
返回32位uuid

Returns:

uuid36
```
public static String uuid36()
```
返回36位uuid

Returns:

firstCharToLowerCase

public static String firstCharToLowerCase(String str)

首字母变小写

firstCharToUpperCase

public static String firstCharToUpperCase(String str)

首字母变大写

toCamelCase

public static String toCamelCase(String stringWithUnderline)

join

public static String join(String[] stringArray,
                          String separator)

randomString

public static final String randomString()

产生8位的随机数字

Returns:

getCRC

public static String getCRC(InputStream in)

计算CRC摘要,8位十六进制数

getCRC

public static String getCRC(String s)

计算CRC摘要,8位十六进制数

substringAfterLastIfExist
```
public static String substringAfterLastIfExist(String source,
                                               String keyword)
```
返回字串，如果查找的字串不存在则返回全部
和substringAfterLast方法不同，substringAfterLast方法在查找不到时返回空串

Parameters:

source - 源字符串

keyword - 查找字

Returns:

isEmpty

public static boolean isEmpty(CharSequence cs)

isEmpty

public static boolean isEmpty(String s)

Checks if a String is empty ("") or null.

 StringUtils.isEmpty(null)      = true
 StringUtils.isEmpty("")        = true
 StringUtils.isEmpty(" ")       = false
 StringUtils.isEmpty("bob")     = false
 StringUtils.isEmpty("  bob  ") = false

isNotEmpty

public static boolean isNotEmpty(String s)

Checks if a String is not empty ("") and not null.

 StringUtils.isNotEmpty(null)      = false
 StringUtils.isNotEmpty("")        = false
 StringUtils.isNotEmpty(" ")       = true
 StringUtils.isNotEmpty("bob")     = true
 StringUtils.isNotEmpty("  bob  ") = true

isBlank

public static boolean isBlank(String s)

Checks if a String is whitespace, empty ("") or null.

 StringUtils.isBlank(null)      = true
 StringUtils.isBlank("")        = true
 StringUtils.isBlank(" ")       = true
 StringUtils.isBlank("bob")     = false
 StringUtils.isBlank("  bob  ") = false

isNotBlank

public static boolean isNotBlank(String s)

Checks if a String 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

getBytes

public static byte[] getBytes(String s,
                              String charsetName)

getUtf8Bytes

public static byte[] getUtf8Bytes(String s)

trim

public static String trim(String s)

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.

 StringUtils.trim(null)          = null
 StringUtils.trim("")            = ""
 StringUtils.trim("     ")       = ""
 StringUtils.trim("abc")         = "abc"
 StringUtils.trim("    abc    ") = "abc"

trimToNull

public static String trimToNull(String s)

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.

 StringUtils.trimToNull(null)          = null
 StringUtils.trimToNull("")            = null
 StringUtils.trimToNull("     ")       = null
 StringUtils.trimToNull("abc")         = "abc"
 StringUtils.trimToNull("    abc    ") = "abc"

trimToEmpty

public static String trimToEmpty(String s)

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.

 StringUtils.trimToEmpty(null)          = ""
 StringUtils.trimToEmpty("")            = ""
 StringUtils.trimToEmpty("     ")       = ""
 StringUtils.trimToEmpty("abc")         = "abc"
 StringUtils.trimToEmpty("    abc    ") = "abc"

trim

public static String[] trim(String[] ss)

defaultIfNull

public static String defaultIfNull(String s,
                                   String defaultStr)

Returns either the passed in String, or if the String is null, the value of defaultStr.

 StringUtils.defaultIfNull(null, "NULL")  = "NULL"
 StringUtils.defaultIfNull("", "NULL")    = ""
 StringUtils.defaultIfNull("bat", "NULL") = "bat"

defaultIfEmpty

public static String defaultIfEmpty(String s,
                                    String defaultStr)

Returns either the passed in String, or if the String is empty or null, the value of defaultStr.

 StringUtils.defaultIfEmpty(null, "NULL")  = "NULL"
 StringUtils.defaultIfEmpty("", "NULL")    = "NULL"
 StringUtils.defaultIfEmpty(" ", "NULL")   = " "
 StringUtils.defaultIfEmpty("bat", "NULL") = "bat"
 StringUtils.defaultIfEmpty("", null)      = null

defaultIfBlank

public static String defaultIfBlank(String s,
                                    String defaultStr)

Returns either the passed in String, or if the String is whitespace, empty ("") or null, the value of defaultStr.

 StringUtils.defaultIfBlank(null, "NULL")  = "NULL"
 StringUtils.defaultIfBlank("", "NULL")    = "NULL"
 StringUtils.defaultIfBlank(" ", "NULL")   = "NULL"
 StringUtils.defaultIfBlank("bat", "NULL") = "bat"
 StringUtils.defaultIfBlank("", null)      = null

equals

public static boolean equals(String s1,
                             String s2)

Compares two CharSequences, returning true if they represent equal sequences of characters.

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

equalsIgnoreCase

public static boolean equalsIgnoreCase(String s1,
                                       String s2)

Compares two CharSequences, returning true if they represent equal sequences of characters, ignoring 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

startsWith

public static boolean startsWith(String s,
                                 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

Parameters:: s - the String to check, may be null; prefix - the prefix to find, may be null
Returns:: true if the String starts with the prefix, case sensitive, or both null
See Also:: String.startsWith(String)

startsWithIgnoreCase

public static boolean startsWithIgnoreCase(String s,
                                           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

See Also:: String.startsWith(String)

startsWithOne

public static int startsWithOne(String s,
                                String... dest)

startsWithOneIgnoreCase

public static int startsWithOneIgnoreCase(String s,
                                          String... dest)

startsWithChar

public static boolean startsWithChar(String s,
                                     char c)

endsWith

public static boolean endsWith(String s,
                               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

See Also:: String.endsWith(String)

endsWithIgnoreCase

public static boolean endsWithIgnoreCase(String s,
                                         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

See Also:: String.endsWith(String)

endsWithOne

public static int endsWithOne(String src,
                              String... dest)

endsWithOneIgnoreCase

public static int endsWithOneIgnoreCase(String s,
                                        String... dest)

endsWithChar

public static boolean endsWithChar(String s,
                                   char c)

indexOf
```
public static int indexOf(String s,
                          String substr,
                          int startIndex,
                          int endIndex)
```
Finds first occurrence of a substring in the given source but within limited range [start, end). It is fastest possible code, but still original String.indexOf(String, int) is much faster (since it uses char[] value directly) and should be used when no range is needed.

Parameters:

s - source string for examination

substr - substring to find

startIndex - starting index

endIndex - ending index

Returns:

index of founded substring or -1 if substring not found

indexOf

public static int indexOf(String s,
                          char c,
                          int startIndex,
                          int endIndex)

Finds the first occurrence of a character in the given source but within limited range (start, end].

indexOfIgnoreCase

public static int indexOfIgnoreCase(String s,
                                    char c,
                                    int startIndex,
                                    int endIndex)

Finds the first occurrence of a character in the given source but within limited range (start, end].

indexOfIgnoreCase
```
public static int indexOfIgnoreCase(String s,
                                    String substr)
```
Finds first index of a substring in the given source string with ignored case.

Parameters:

s - source string for examination

substr - substring to find

Returns:

index of founded substring or -1 if substring is not found

See Also:

indexOfIgnoreCase(String, String, int)

indexOfIgnoreCase
```
public static int indexOfIgnoreCase(String s,
                                    String substr,
                                    int startIndex)
```
Finds first index of a substring in the given source string with ignored case. This seems to be the fastest way doing this, with common string length and content (of course, with no use of Boyer-Mayer type of algorithms). Other implementations are slower: getting char array first, lower casing the source string, using String.regionMatch etc.

Parameters:

s - source string for examination

substr - substring to find

startIndex - starting index from where search begins

Returns:

index of founded substring or -1 if substring is not found

indexOfIgnoreCase
```
public static int indexOfIgnoreCase(String s,
                                    String substr,
                                    int startIndex,
                                    int endIndex)
```
Finds first index of a substring in the given source string and range with ignored case.

Parameters:

s - source string for examination

substr - substring to find

startIndex - starting index from where search begins

endIndex - endint index

Returns:

index of founded substring or -1 if substring is not found

See Also:

indexOfIgnoreCase(String, String, int)

indexOf
```
public static int[] indexOf(String s,
                            String[] arr)
```
Finds the very first index of a substring from the specified array. It returns an int[2] where int[0] represents the substring index and int[1] represents position where substring was found. Returns null if noting found.

Parameters:

s - source string

arr - string array

indexOf
```
public static int[] indexOf(String s,
                            String[] arr,
                            int start)
```
Finds the very first index of a substring from the specified array. It returns an int[2] where int[0] represents the substring index and int[1] represents position where substring was found. Returns null if noting found.

Parameters:

s - source string

arr - string array

start - starting position

indexOf
```
public static int[] indexOf(String s,
                            char[] c)
```
Finds the very first index of a substring from the specified array. It returns an int[2] where int[0] represents the substring index and int[1] represents position where substring was found. Returns null if noting found.

Parameters:

s - source string

c - char array

indexOf
```
public static int[] indexOf(String s,
                            char[] c,
                            int start)
```
Finds the very first index of a char from the specified array. It returns an int[2] where int[0] represents the char index and int[1] represents position where char was found. Returns null if noting found.

Parameters:

s - source string

c - char array

start - starting position

indexOfIgnoreCase
```
public static int[] indexOfIgnoreCase(String s,
                                      String[] arr)
```
Finds the very first index of a substring from the specified array. It returns an int[2] where int[0] represents the substring index and int[1] represents position where substring was found. Returns null if noting found.

Parameters:

s - source string

arr - string array

indexOfIgnoreCase
```
public static int[] indexOfIgnoreCase(String s,
                                      String[] arr,
                                      int start)
```
Finds the very first index of a substring from the specified array. It returns an int[2] where int[0] represents the substring index and int[1] represents position where substring was found. Returns null if noting found.

Parameters:

s - source string

arr - string array

start - starting position

lastIndexOfIgnoreCase
```
public static int lastIndexOfIgnoreCase(String s,
                                        String substr)
```
Finds last index of a substring in the given source string with ignored case.

Parameters:

s - source string

substr - substring to find

Returns:

last index of founded substring or -1 if substring is not found

See Also:

indexOfIgnoreCase(String, String, int), lastIndexOfIgnoreCase(String, String, int)

lastIndexOfIgnoreCase
```
public static int lastIndexOfIgnoreCase(String s,
                                        String substr,
                                        int startIndex)
```
Finds last index of a substring in the given source string with ignored case.

Parameters:

s - source string for examination

substr - substring to find

startIndex - starting index from where search begins

Returns:

last index of founded substring or -1 if substring is not found

See Also:

indexOfIgnoreCase(String, String, int)

lastIndexOfIgnoreCase
```
public static int lastIndexOfIgnoreCase(String s,
                                        String sub,
                                        int startIndex,
                                        int endIndex)
```
Finds last index of a substring in the given source string with ignored case in specified range.

Parameters:

s - source to examine

sub - substring to find

startIndex - starting index

endIndex - end index

Returns:

last index of founded substring or -1 if substring is not found

lastIndexOf
```
public static int lastIndexOf(String s,
                              String sub,
                              int startIndex,
                              int endIndex)
```
Finds last index of a substring in the given source string in specified range [end, start] See indexOf(String, String, int, int) for details about the speed.

Parameters:

s - source to examine

sub - substring to find

startIndex - starting index

endIndex - end index

Returns:

last index of founded substring or -1 if substring is not found

lastIndexOf

public static int lastIndexOf(String s,
                              char c,
                              int startIndex,
                              int endIndex)

Finds last index of a character in the given source string in specified range [end, start]

lastIndexOfIgnoreCase

public static int lastIndexOfIgnoreCase(String s,
                                        char c,
                                        int startIndex,
                                        int endIndex)

Finds last index of a character in the given source string in specified range [end, start]

lastIndexOf
```
public static int[] lastIndexOf(String s,
                                String[] arr)
```
Finds the very last index of a substring from the specified array. It returns an int[2] where int[0] represents the substring index and int[1] represents position where substring was found. Returns null if noting found.

Parameters:

s - source string

arr - string array

lastIndexOf
```
public static int[] lastIndexOf(String s,
                                String[] arr,
                                int fromIndex)
```
Finds the very last index of a substring from the specified array. It returns an int[2] where int[0] represents the substring index and int[1] represents position where substring was found. Returns null if noting found.

Parameters:

s - source string

arr - string array

fromIndex - starting position

lastIndexOf
```
public static int[] lastIndexOf(String s,
                                char[] c)
```
Finds the very last index of a substring from the specified array. It returns an int[2] where int[0] represents the substring index and int[1] represents position where substring was found. Returns null if noting found.

Parameters:

s - source string

c - char array

lastIndexOf
```
public static int[] lastIndexOf(String s,
                                char[] c,
                                int fromIndex)
```
Finds the very last index of a substring from the specified array. It returns an int[2] where int[0] represents the substring index and int[1] represents position where substring was found. Returns null if noting found.

Parameters:

s - source string

c - char array

fromIndex - starting position

lastIndexOfIgnoreCase
```
public static int[] lastIndexOfIgnoreCase(String s,
                                          String[] arr)
```
Finds the very last index of a substring from the specified array. It returns an int[2] where int[0] represents the substring index and int[1] represents position where substring was found. Returns null if noting found.

Parameters:

s - source string

arr - string array

Returns:

int[2]

lastIndexOfIgnoreCase
```
public static int[] lastIndexOfIgnoreCase(String s,
                                          String[] arr,
                                          int fromIndex)
```
Finds the very last index of a substring from the specified array. It returns an int[2] where int[0] represents the substring index and int[1] represents position where substring was found. Returns null if noting found.

Parameters:

s - source string

arr - string array

fromIndex - starting position

substring

public static String substring(String s,
                               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"

substring

public static String substring(String s,
                               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"

substringBefore

public static String substringBefore(String s,
                                     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"

substringAfter

public static String substringAfter(String s,
                                    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"

substringBeforeLast

public static String substringBeforeLast(String s,
                                         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"

substringAfterLast

public static String substringAfterLast(String s,
                                        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")     = ""

substringBetween

public static String substringBetween(String s,
                                      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"

substringBetween

public static String substringBetween(String s,
                                      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"

left

public static String left(String s,
                          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 empty String is returned 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"

right

public static String right(String s,
                           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 empty String is returned 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"

mid

public static String mid(String s,
                         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 empty String is returned if len is negative or exceeds the length of str.

 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"

repeat

public static String repeat(String s,
                            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) = ""

repeat

public static String repeat(String s,
                            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)  = "?, ?, ?"

repeat
```
public static String repeat(char ch,
                            int repeat)
```
Returns padding using the specified delimiter repeated to a given length.
```
 StringUtils.repeat('e', 0)  = ""
 StringUtils.repeat('e', 3)  = "eee"
 StringUtils.repeat('e', -2) = ""
 
```
Note: this method doesn't not support padding with Unicode Supplementary Characters as they require a pair of chars to be represented. If you are needing to support full I18N of your applications consider using repeat(String, int) instead.
See Also:

repeat(String, int)

leftPad

public static String leftPad(String str,
                             int size)

leftPad

public static String leftPad(String str,
                             int size,
                             char padChar)

leftPad

public static String leftPad(String str,
                             int size,
                             String padStr)

rightPad

public static String rightPad(String str,
                              int size)

rightPad

public static String rightPad(String str,
                              int size,
                              char padChar)

rightPad

public static String rightPad(String str,
                              int size,
                              String padStr)

center

public static String center(String str,
                            int size)

center

public static String center(String str,
                            int size,
                            char padChar)

upperCase
```
public 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).
Parameters:

str - the String to upper case, may be null

Returns:

the upper cased String, null if null String input

upperCase
```
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"
 
```
Parameters:

str - the String to upper case, may be null

locale - the locale that defines the case transformation rules, must not be null

Returns:

the upper cased String, null if null String input

Since:

2.5

lowerCase
```
public 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).
Parameters:

str - the String to lower case, may be null

Returns:

the lower cased String, null if null String input

lowerCase
```
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"
 
```
Parameters:

str - the String to lower case, may be null

locale - the locale that defines the case transformation rules, must not be null

Returns:

the lower cased String, null if null String input

Since:

2.5

reverse

public static String reverse(String s)

deleteWhitespace

public static String deleteWhitespace(String s)

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"

Parameters:: s - the String to delete whitespace from, may be null
Returns:: the String without whitespaces, null if null String input

removeStart

public static String removeStart(String s,
                                 String remove)

Removes a substring only if it is at the beginning 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"

removeStartIgnoreCase

public static String removeStartIgnoreCase(String s,
                                           String remove)

Case insensitive removal of a substring if it is at the beginning 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"

removeEnd

public static String removeEnd(String s,
                               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"

removeEndIgnoreCase

public static String removeEndIgnoreCase(String s,
                                         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")

remove

public static String remove(String s,
                            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"

remove

public static String remove(String s,
                            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"

removeChars

public static String removeChars(String s,
                                 String chars)

Removes all characters contained in provided string.

Parameters:: s - source string; chars - string containing characters to remove

removeChars

public static String removeChars(String s,
                                 char... chars)

Removes set of characters from string.

Parameters:: s - string; chars - characters to remove

prefix

public static String prefix(String s,
                            String prefix)

suffix

public static String suffix(String s,
                            String suffix)

replaceOnce

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"

See Also:: replace(String text, String searchString, String replacement, int max)

replacePattern
```
public static String replacePattern(String source,
                                    String regex,
                                    String replacement)
```
Replaces each substring of the source String that matches the given regular expression with the given replacement using the Pattern.DOTALL option. DOTALL is also know as single-line mode in Perl. This call is also equivalent to:
- source.replaceAll("(?s)" + regex, replacement)
- Pattern.compile(regex, Pattern.DOTALL).matcher(source).replaceAll(replacement)
See Also:

String.replaceAll(String, String), Pattern.DOTALL

replace

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"

replace

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"

replaceEach

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"

replaceEachRepeatedly

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.

  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) = IllegalStateException
  StringUtils.replaceEach("abcde", new String[]{"ab", "d"}, new String[]{"d", "ab"}, false) = "dcabe"

replaceChars

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"

replaceChars

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"

split

public static String[] split(String str,
                             String delimiter)

split

public static String[] split(String str,
                             char delimiter)

splitChars

public static String[] splitChars(String str,
                                  String delimiters)

splitChars

public static String[] splitChars(String str,
                                  char... delimiters)

splitCSV
```
public static String[] splitCSV(String str)
```
按逗号分隔，两边加引号的不分割（CSV 规则）.

join

public static String join(String... parts)

join

public static String join(Iterable<?> elements,
                          String separator)

join

public static String join(Iterator<?> elements,
                          String separator)

join

public static String join(Object[] elements,
                          String separator)

count

public static int count(String source,
                        String substr)

count

public static int count(String source,
                        String substr,
                        int start)

count

public static int count(String source,
                        char c)

count

public static int count(String source,
                        char c,
                        int start)

contains
```
public static boolean contains(CharSequence seq,
                               int searchChar)
```
Checks if CharSequence contains a search character, handling null. This method uses String.indexOf(int) if possible.

A null or empty ("") CharSequence will return false.
```
 StringUtils.contains(null, *)    = false
 StringUtils.contains("", *)      = false
 StringUtils.contains("abc", 'a') = true
 StringUtils.contains("abc", 'z') = false
 
```
Parameters:

seq - the CharSequence to check, may be null

searchChar - the character to find

Returns:

true if the CharSequence contains the search character, false if not or null string input

Since:

2.0, 3.0 Changed signature from contains(String, int) to contains(CharSequence, int)

contains
```
public static boolean contains(CharSequence seq,
                               CharSequence searchSeq)
```
Checks if CharSequence contains a search CharSequence, handling null. This method uses String.indexOf(String) if possible.

A null CharSequence 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
 
```
Parameters:

seq - the CharSequence to check, may be null

searchSeq - the CharSequence to find, may be null

Returns:

true if the CharSequence contains the search CharSequence, false if not or null string input

Since:

2.0, 3.0 Changed signature from contains(String, String) to contains(CharSequence, CharSequence)

containsIgnoreCase
```
public static boolean containsIgnoreCase(CharSequence str,
                                         CharSequence searchStr)
```
Checks if CharSequence contains a search CharSequence irrespective of case, handling null. Case-insensitivity is defined as by String.equalsIgnoreCase(String).
A null CharSequence 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
 
```
Parameters:

str - the CharSequence to check, may be null

searchStr - the CharSequence to find, may be null

Returns:

true if the CharSequence contains the search CharSequence irrespective of case or false if not or null string input

Since:

3.0 Changed signature from containsIgnoreCase(String, String) to containsIgnoreCase(CharSequence, CharSequence)

swapCase
```
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.
- Upper case character converts to Lower case
- Title case character converts to Lower case
- Lower case character converts 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.
Parameters:

str - the String to swap case, may be null

Returns:

the changed String, null if null String input

Class StringUtils

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

StringUtils

Method Detail

uuid32

uuid36

firstCharToLowerCase

firstCharToUpperCase

toCamelCase

join

randomString

getCRC

getCRC

substringAfterLastIfExist

isEmpty

isEmpty

isNotEmpty

isBlank

isNotBlank

getBytes

getUtf8Bytes

trim

trimToNull

trimToEmpty

trim

defaultIfNull

defaultIfEmpty

defaultIfBlank

equals

equalsIgnoreCase

startsWith

startsWithIgnoreCase

startsWithOne

startsWithOneIgnoreCase

startsWithChar

endsWith

endsWithIgnoreCase

endsWithOne

endsWithOneIgnoreCase

endsWithChar

indexOf

indexOf

indexOfIgnoreCase

indexOfIgnoreCase

indexOfIgnoreCase

indexOfIgnoreCase

indexOf

indexOf

indexOf

indexOf

indexOfIgnoreCase

indexOfIgnoreCase

lastIndexOfIgnoreCase

lastIndexOfIgnoreCase

lastIndexOfIgnoreCase

lastIndexOf

lastIndexOf

lastIndexOfIgnoreCase

lastIndexOf

lastIndexOf

lastIndexOf

lastIndexOf

lastIndexOfIgnoreCase

lastIndexOfIgnoreCase

substring

substring

substringBefore

substringAfter

substringBeforeLast

substringAfterLast

substringBetween

substringBetween

left

right

mid

repeat

repeat