java.lang.Object

com.xingyuv.captcha.util.StringUtils

public class StringUtils extends Object

字段概要

字段

修饰符和类型

字段

说明

static final String

EMPTY

The empty String "".

static final int

INDEX_NOT_FOUND

Represents a failed index search.

private static final int

PAD_LIMIT

The maximum size to which the padding constant(s) can expand.
构造器概要

构造器

构造器

说明

StringUtils()

StringUtils instances should NOT be constructed in standard programming.
方法概要

修饰符和类型

方法

说明

static String

clean(String str)

已过时。
Use the clearer named trimToEmpty(String).

static boolean

contains(String str, char 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

containsIgnoreCase(String str, String searchStr)

Checks if String contains a search String irrespective of case, handling null.

static boolean

equals(String str1, String str2)

Compares two Strings, 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 int

indexOf(String str, char searchChar)

Finds the first index within a String, handling null.

static int

indexOf(String str, char 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(String str, String[] searchStrs)

Find the first index of any of a set of potential substrings.

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

isBlank(String str)

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

static boolean

isEmpty(String str)

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

static boolean

isNotBlank(String str)

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

static boolean

isNotEmpty(String str)

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

static int

lastIndexOf(String str, char searchChar)

Finds the last index within a String, handling null.

static int

lastIndexOf(String str, char 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

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.

private static int

ordinalIndexOf(String str, String searchStr, int ordinal, boolean lastIndex)

Finds the n-th index within a String, handling null.

static String

right(String str, int len)

Gets the rightmost len characters of a String.

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[]

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

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.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

字段详细资料
- EMPTY
  
  public static final String EMPTY
  
  The empty String "".
  从以下版本开始:
  
  2.0
  
  另请参阅:
  
  常量字段值
- INDEX_NOT_FOUND
  
  public static final int INDEX_NOT_FOUND
  
  Represents a failed index search.
  从以下版本开始:
  
  2.1
  
  另请参阅:
  
  常量字段值
- PAD_LIMIT
  
  private static final int PAD_LIMIT
  
  The maximum size to which the padding constant(s) can expand.
  另请参阅:
  
  常量字段值
构造器详细资料
- StringUtils
  
  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.
方法详细资料
- isEmpty
  
  public static boolean isEmpty(String str)
  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
  
  NOTE: This method changed in Lang version 2.0. It no longer trims the String. That functionality is available in isBlank().
  参数:
  
  str - the String to check, may be null
  
  返回:
  
  true if the String is empty or null
- isNotEmpty
  
  public static boolean isNotEmpty(String str)
  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
  参数:
  
  str - the String to check, may be null
  
  返回:
  
  true if the String is not empty and not null
- isBlank
  
  public static boolean isBlank(String str)
  Checks if a String is whitespace, empty ("") or null.
  
  StringUtils.isBlank(null) = true StringUtils.isBlank("null") = true StringUtils.isBlank("") = true StringUtils.isBlank(" ") = true StringUtils.isBlank("bob") = false StringUtils.isBlank(" bob ") = false
  参数:
  
  str - the String to check, may be null
  
  返回:
  
  true if the String is null, empty or whitespace
  
  从以下版本开始:
  
  2.0
- isNotBlank
  
  public static boolean isNotBlank(String str)
  Checks if a String is not empty (""), not null and not whitespace only.
  
  StringUtils.isNotBlank(null) = false StringUtils.isNotBlank("null") = false StringUtils.isNotBlank("") = false StringUtils.isNotBlank(" ") = false StringUtils.isNotBlank("bob") = true StringUtils.isNotBlank(" bob ") = true
  参数:
  
  str - the String to check, may be null
  
  返回:
  
  true if the String is not empty and not null and not whitespace
  
  从以下版本开始:
  
  2.0
- clean
  
  public static String clean(String str)
  
  已过时。
  Use the clearer named trimToEmpty(String). Method will be removed in Commons Lang 3.0.
  Removes control characters (char <= 32) from both ends of this String, handling null by returning an empty String ("").
  
  StringUtils.clean(null) = "" StringUtils.clean("") = "" StringUtils.clean("abc") = "abc" StringUtils.clean(" abc ") = "abc" StringUtils.clean(" ") = ""
  参数:
  
  str - the String to clean, may be null
  
  返回:
  
  the trimmed text, never null
  
  另请参阅:
  
  String.trim()
- trim
  
  public 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"
  参数:
  
  str - the String to be trimmed, may be null
  
  返回:
  
  the trimmed string, null if null String input
- trimToNull
  
  public 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"
  参数:
  
  str - the String to be trimmed, may be null
  
  返回:
  
  the trimmed String, null if only chars <= 32, empty or null String input
  
  从以下版本开始:
  
  2.0
- trimToEmpty
  
  public 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"
  参数:
  
  str - the String to be trimmed, may be null
  
  返回:
  
  the trimmed String, or an empty String if null input
  
  从以下版本开始:
  
  2.0
- strip
  
  public 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"
  参数:
  
  str - the String to remove whitespace from, may be null
  
  返回:
  
  the stripped String, null if null String input
- stripToNull
  
  public 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"
  参数:
  
  str - the String to be stripped, may be null
  
  返回:
  
  the stripped String, null if whitespace, empty or null String input
  
  从以下版本开始:
  
  2.0
- stripToEmpty
  
  public 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"
  参数:
  
  str - the String to be stripped, may be null
  
  返回:
  
  the trimmed String, or an empty String if null input
  
  从以下版本开始:
  
  2.0
- strip
  
  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"
  参数:
  
  str - the String to remove characters from, may be null
  
  stripChars - the characters to remove, null treated as whitespace
  
  返回:
  
  the stripped String, null if null String input
- stripStart
  
  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 "
  参数:
  
  str - the String to remove characters from, may be null
  
  stripChars - the characters to remove, null treated as whitespace
  
  返回:
  
  the stripped String, null if null String input
- stripEnd
  
  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" StringUtils.stripEnd("120.00", ".0") = "12"
  参数:
  
  str - the String to remove characters from, may be null
  
  stripChars - the set of characters to remove, null treated as whitespace
  
  返回:
  
  the stripped String, null if null String input
- stripAll
  
  public 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]
  参数:
  
  strs - the array to remove whitespace from, may be null
  
  返回:
  
  the stripped Strings, null if null array input
- stripAll
  
  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 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. 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]
  参数:
  
  strs - the array to remove characters from, may be null
  
  stripChars - the characters to remove, null treated as whitespace
  
  返回:
  
  the stripped Strings, null if null array input
- equals
  
  public static boolean equals(String str1, String str2)
  Compares two Strings, 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
  参数:
  
  str1 - the first String, may be null
  
  str2 - the second String, may be null
  
  返回:
  
  true if the Strings are equal, case sensitive, or both null
  
  另请参阅:
  
  String.equals(Object)
- equalsIgnoreCase
  
  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
  参数:
  
  str1 - the first String, may be null
  
  str2 - the second String, may be null
  
  返回:
  
  true if the Strings are equal, case insensitive, or both null
  
  另请参阅:
  
  String.equalsIgnoreCase(String)
- indexOf
  
  public static int indexOf(String str, char 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
  参数:
  
  str - the String to check, may be null
  
  searchChar - the character to find
  
  返回:
  
  the first index of the search character, -1 if no match or null string input
  
  从以下版本开始:
  
  2.0
- indexOf
  
  public static int indexOf(String str, char 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
  参数:
  
  str - the String to check, may be null
  
  searchChar - the character to find
  
  startPos - the start position, negative treated as zero
  
  返回:
  
  the first index of the search character, -1 if no match or null string input
  
  从以下版本开始:
  
  2.0
- indexOf
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  返回:
  
  the first index of the search String, -1 if no match or null string input
  
  从以下版本开始:
  
  2.0
- ordinalIndexOf
  
  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))
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  ordinal - the n-th searchStr to find
  
  返回:
  
  the n-th index of the search String, -1 (INDEX_NOT_FOUND) if no match or null string input
  
  从以下版本开始:
  
  2.1
- ordinalIndexOf
  
  private static int ordinalIndexOf(String str, String searchStr, int ordinal, boolean lastIndex)
  
  Finds the n-th index within a String, handling null. This method uses String.indexOf(String).
  
  A null String will return -1.
  
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  ordinal - the n-th searchStr to find
  
  lastIndex - true if lastOrdinalIndexOf() otherwise false if ordinalIndexOf()
  
  返回:
  
  the n-th index of the search String, -1 (INDEX_NOT_FOUND) if no match or null string input
- indexOf
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  startPos - the start position, negative treated as zero
  
  返回:
  
  the first index of the search String, -1 if no match or null string input
  
  从以下版本开始:
  
  2.0
- indexOfIgnoreCase
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  返回:
  
  the first index of the search String, -1 if no match or null string input
  
  从以下版本开始:
  
  2.5
- indexOfIgnoreCase
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  startPos - the start position, negative treated as zero
  
  返回:
  
  the first index of the search String, -1 if no match or null string input
  
  从以下版本开始:
  
  2.5
- lastIndexOf
  
  public static int lastIndexOf(String str, char 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
  参数:
  
  str - the String to check, may be null
  
  searchChar - the character to find
  
  返回:
  
  the last index of the search character, -1 if no match or null string input
  
  从以下版本开始:
  
  2.0
- lastIndexOf
  
  public static int lastIndexOf(String str, char 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
  参数:
  
  str - the String to check, may be null
  
  searchChar - the character to find
  
  startPos - the start position
  
  返回:
  
  the last index of the search character, -1 if no match or null string input
  
  从以下版本开始:
  
  2.0
- lastIndexOf
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  返回:
  
  the last index of the search String, -1 if no match or null string input
  
  从以下版本开始:
  
  2.0
- lastOrdinalIndexOf
  
  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)
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  ordinal - the n-th last searchStr to find
  
  返回:
  
  the n-th last index of the search String, -1 (INDEX_NOT_FOUND) if no match or null string input
  
  从以下版本开始:
  
  2.5
- lastIndexOf
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  startPos - the start position, negative treated as zero
  
  返回:
  
  the first index of the search String, -1 if no match or null string input
  
  从以下版本开始:
  
  2.0
- lastIndexOfIgnoreCase
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  返回:
  
  the first index of the search String, -1 if no match or null string input
  
  从以下版本开始:
  
  2.5
- lastIndexOfIgnoreCase
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  startPos - the start position
  
  返回:
  
  the first index of the search String, -1 if no match or null string input
  
  从以下版本开始:
  
  2.5
- contains
  
  public static boolean contains(String str, char 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
  参数:
  
  str - the String to check, may be null
  
  searchChar - the character to find
  
  返回:
  
  true if the String contains the search character, false if not or null string input
  
  从以下版本开始:
  
  2.0
- contains
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  返回:
  
  true if the String contains the search String, false if not or null string input
  
  从以下版本开始:
  
  2.0
- containsIgnoreCase
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStr - the String to find, may be null
  
  返回:
  
  true if the String contains the search String irrespective of case or false if not or null string input
- indexOfAny
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStrs - the Strings to search for, may be null
  
  返回:
  
  the first index of any of the searchStrs in str, -1 if no match
- lastIndexOfAny
  
  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
  参数:
  
  str - the String to check, may be null
  
  searchStrs - the Strings to search for, may be null
  
  返回:
  
  the last index of any of the Strings, -1 if no match
- substring
  
  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"
  参数:
  
  str - the String to get the substring from, may be null
  
  start - the position to start from, negative means count back from the end of the String by this many characters
  
  返回:
  
  substring from start position, null if null String input
- substring
  
  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"
  参数:
  
  str - the String to get the substring from, may be null
  
  start - the position to start from, negative means count back from the end of the String by this many characters
  
  end - the position to end at (exclusive), negative means count back from the end of the String by this many characters
  
  返回:
  
  substring from start position to end positon, null if null String input
- left
  
  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 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"
  参数:
  
  str - the String to get the leftmost characters from, may be null
  
  len - the length of the required String
  
  返回:
  
  the leftmost characters, null if null String input
- right
  
  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 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"
  参数:
  
  str - the String to get the rightmost characters from, may be null
  
  len - the length of the required String
  
  返回:
  
  the rightmost characters, null if null String input
- mid
  
  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 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"
  参数:
  
  str - the String to get the characters from, may be null
  
  pos - the position to start from, negative treated as zero
  
  len - the length of the required String
  
  返回:
  
  the middle characters, null if null String input
- substringBefore
  
  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"
  参数:
  
  str - the String to get a substring from, may be null
  
  separator - the String to search for, may be null
  
  返回:
  
  the substring before the first occurrence of the separator, null if null String input
  
  从以下版本开始:
  
  2.0
- substringAfter
  
  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"
  参数:
  
  str - the String to get a substring from, may be null
  
  separator - the String to search for, may be null
  
  返回:
  
  the substring after the first occurrence of the separator, null if null String input
  
  从以下版本开始:
  
  2.0
- substringBeforeLast
  
  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"
  参数:
  
  str - the String to get a substring from, may be null
  
  separator - the String to search for, may be null
  
  返回:
  
  the substring before the last occurrence of the separator, null if null String input
  
  从以下版本开始:
  
  2.0
- substringAfterLast
  
  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") = ""
  参数:
  
  str - the String to get a substring from, may be null
  
  separator - the String to search for, may be null
  
  返回:
  
  the substring after the last occurrence of the separator, null if null String input
  
  从以下版本开始:
  
  2.0
- substringBetween
  
  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"
  参数:
  
  str - the String containing the substring, may be null
  
  tag - the String before and after the substring, may be null
  
  返回:
  
  the substring, null if no match
  
  从以下版本开始:
  
  2.0
- substringBetween
  
  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"
  参数:
  
  str - the String containing the substring, may be null
  
  open - the String before the substring, may be null
  
  close - the String after the substring, may be null
  
  返回:
  
  the substring, null if no match
  
  从以下版本开始:
  
  2.0

类 StringUtils

字段概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

字段详细资料

EMPTY

INDEX_NOT_FOUND

PAD_LIMIT

构造器详细资料

StringUtils

方法详细资料

isEmpty

isNotEmpty

isBlank

isNotBlank

clean

trim

trimToNull

trimToEmpty

strip

stripToNull

stripToEmpty

strip

stripStart

stripEnd

stripAll

stripAll

equals

equalsIgnoreCase

indexOf

indexOf

indexOf

ordinalIndexOf

ordinalIndexOf

indexOf

indexOfIgnoreCase

indexOfIgnoreCase

lastIndexOf

lastIndexOf

lastIndexOf

lastOrdinalIndexOf

lastIndexOf

lastIndexOfIgnoreCase

lastIndexOfIgnoreCase

contains

contains

containsIgnoreCase

indexOfAny

lastIndexOfAny

substring

substring

left

right

mid

substringBefore

substringAfter

substringBeforeLast

substringAfterLast

substringBetween

substringBetween