com.baidu.jprotobuf.pbrpc.utils

类 StringUtils

java.lang.Object

com.baidu.jprotobuf.pbrpc.utils.StringUtils

public class StringUtils
extends Object

Utility class for String.

从以下版本开始:

1.0

作者:

xiemalin

字段概要

字段

限定符和类型	字段和说明
static String	EMPTY_STRING The Constant EMPTY_STRING.

构造器概要

构造器

构造器和说明
StringUtils()

方法概要

限定符和类型	方法和说明
static String	escapeJava(String str) Escapes the characters in a String using Java String rules.
static void	escapeJava(Writer out, String str) Escapes the characters in a String using Java String rules to a Writer.
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 String[]	split(String str) Splits the provided text into an array, using whitespace as the separator.
static String[]	split(String str, char separatorChar) Splits the provided text into an array, separator specified.
static String[]	split(String str, String separatorChars) Splits the provided text into an array, separators specified.
static String[]	split(String str, String separatorChars, int max) Splits the provided text into an array with a maximum length, separators specified.
static String[]	splitByWholeSeparator(String str, String separator) Splits the provided text into an array, separator string specified.
static String[]	splitByWholeSeparator(String str, String separator, int max) Splits the provided text into an array, separator string specified.
static String[]	splitByWholeSeparatorPreserveAllTokens(String str, String separator) Splits the provided text into an array, separator string specified.
static String[]	splitByWholeSeparatorPreserveAllTokens(String str, String separator, int max) Splits the provided text into an array, separator string specified.
static int	stringToInt(String str, int defaultValue) 已过时。 Use toInt(String, int) This method will be removed in Commons Lang 3.0
static int	toInt(String str) Convert a String to an int, returning zero if the conversion fails.
static int	toInt(String str, int defaultValue) Convert a String to an int, returning a default value if the conversion fails.
static long	toLong(String str) Convert a String to an long, returning a default value if the conversion fails.
static long	toLong(String str, long defaultValue) Convert a String to an long, returning a default value if the conversion fails.
static String	unescapeJava(String str) Unescapes any Java literals found in the String.
static void	unescapeJava(Writer out, String str) Unescapes any Java literals found in the String to a Writer.

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_STRING

public static final String EMPTY_STRING

The Constant EMPTY_STRING.

另请参阅:

常量字段值

构造器详细资料

StringUtils

public StringUtils()

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

isBlank

public static boolean isBlank(String str)

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
 

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

toInt

public static int toInt(String str)

Convert a String to an int, returning zero if the conversion fails.

If the string is null, zero is returned.

   NumberUtils.toInt(null) = 0
   NumberUtils.toInt("")   = 0
   NumberUtils.toInt("1")  = 1
 

参数:

str - the string to convert, may be null

返回:

the int represented by the string, or zero if conversion fails

从以下版本开始:

2.1

stringToInt

public static int stringToInt(String str,
                              int defaultValue)

已过时。 Use toInt(String, int) This method will be removed in Commons Lang 3.0

Convert a String to an int, returning a default value if the conversion fails.

If the string is null, the default value is returned.

   NumberUtils.stringToInt(null, 1) = 1
   NumberUtils.stringToInt("", 1)   = 1
   NumberUtils.stringToInt("1", 0)  = 1
 

参数:

str - the string to convert, may be null

defaultValue - the default value

返回:

the int represented by the string, or the default if conversion fails

toInt

public static int toInt(String str,
                        int defaultValue)

Convert a String to an int, returning a default value if the conversion fails.

If the string is null, the default value is returned.

   NumberUtils.toInt(null, 1) = 1
   NumberUtils.toInt("", 1)   = 1
   NumberUtils.toInt("1", 0)  = 1
 

参数:

str - the string to convert, may be null

defaultValue - the default value

返回:

the int represented by the string, or the default if conversion fails

从以下版本开始:

2.1

toLong

public static long toLong(String str)

Convert a String to an long, returning a default value if the conversion fails.

If the string is null, the default value is returned.

   NumberUtils.toLong(null) = 0
   NumberUtils.toLong("")   = 0
   NumberUtils.toLong("1")  = 1
 

参数:

str - the string to convert, may be null

返回:

the long represented by the string, or the default if conversion fails

从以下版本开始:

2.1

toLong

public static long toLong(String str,
                          long defaultValue)

Convert a String to an long, returning a default value if the conversion fails.

If the string is null, the default value is returned.

   NumberUtils.toLong(null, 1) = 1
   NumberUtils.toLong("", 1)   = 1
   NumberUtils.toLong("1", 0)  = 1
 

参数:

str - the string to convert, may be null

defaultValue - the default value

返回:

the long represented by the string, or the default if conversion fails

从以下版本开始:

2.1

escapeJava

public static String escapeJava(String str)

Escapes the characters in a String using Java String rules.

Deals correctly with quotes and control-chars (tab, backslash, cr, ff, etc.)

So a tab becomes the characters '\\' and 't'.

The only difference between Java strings and JavaScript strings is that in JavaScript, a single quote must be escaped.

Example:

 input string: He didn't say, "Stop!"
 output string: He didn't say, \"Stop!\"
 

参数:

str - String to escape values in, may be null

返回:

String with escaped values, null if null string input

escapeJava

public static void escapeJava(Writer out,
                              String str)
                       throws IOException

Escapes the characters in a String using Java String rules to a Writer.

A null string input has no effect.

参数:

out - Writer to write escaped string into

str - String to escape values in, may be null

抛出:

IOException - if error occurs on underlying Writer

IllegalArgumentException - if the Writer is null

另请参阅:

escapeJava(java.lang.String)

unescapeJava

public static String unescapeJava(String str)

Unescapes any Java literals found in the String. For example, it will turn a sequence of '\' and 'n' into a newline character, unless the '\' is preceded by another '\'.

参数:

str - the String to unescape, may be null

返回:

a new unescaped String, null if null string input

unescapeJava

public static void unescapeJava(Writer out,
                                String str)
                         throws IOException

Unescapes any Java literals found in the String to a Writer.

For example, it will turn a sequence of '\' and 'n' into a newline character, unless the '\' is preceded by another '\'.

A null string input has no effect.

参数:

out - the Writer used to output unescaped characters

str - the String to unescape, may be null

抛出:

IOException - if error occurs on underlying Writer

IllegalArgumentException - if the Writer is null

split

public static String[] split(String str)

Splits the provided text into an array, using whitespace as the separator. Whitespace is defined by Character.isWhitespace(char).

The separator is not included in the returned String array. Adjacent separators are treated as one separator. For more control over the split use the StrTokenizer class.

A null input String returns null.

 StringUtils.split(null)       = null
 StringUtils.split("")         = []
 StringUtils.split("abc def")  = ["abc", "def"]
 StringUtils.split("abc  def") = ["abc", "def"]
 StringUtils.split(" abc ")    = ["abc"]
 

参数:

str - the String to parse, may be null

返回:

an array of parsed Strings, null if null String input

split

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

Splits the provided text into an array, separator specified. This is an alternative to using StringTokenizer.

The separator is not included in the returned String array. Adjacent separators are treated as one separator. For more control over the split use the StrTokenizer class.

A null input String returns null.

 StringUtils.split(null, *)         = null
 StringUtils.split("", *)           = []
 StringUtils.split("a.b.c", '.')    = ["a", "b", "c"]
 StringUtils.split("a..b.c", '.')   = ["a", "b", "c"]
 StringUtils.split("a:b:c", '.')    = ["a:b:c"]
 StringUtils.split("a b c", ' ')    = ["a", "b", "c"]
 

参数:

str - the String to parse, may be null

separatorChar - the character used as the delimiter

返回:

an array of parsed Strings, null if null String input

从以下版本开始:

2.0

split

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

Splits the provided text into an array, separators specified. This is an alternative to using StringTokenizer.

The separator is not included in the returned String array. Adjacent separators are treated as one separator. For more control over the split use the StrTokenizer class.

A null input String returns null. A null separatorChars splits on whitespace.

 StringUtils.split(null, *)         = null
 StringUtils.split("", *)           = []
 StringUtils.split("abc def", null) = ["abc", "def"]
 StringUtils.split("abc def", " ")  = ["abc", "def"]
 StringUtils.split("abc  def", " ") = ["abc", "def"]
 StringUtils.split("ab:cd:ef", ":") = ["ab", "cd", "ef"]
 

参数:

str - the String to parse, may be null

separatorChars - the characters used as the delimiters, null splits on whitespace

返回:

an array of parsed Strings, null if null String input

split

public static String[] split(String str,
                             String separatorChars,
                             int max)

Splits the provided text into an array with a maximum length, separators specified.

The separator is not included in the returned String array. Adjacent separators are treated as one separator.

A null input String returns null. A null separatorChars splits on whitespace.

If more than max delimited substrings are found, the last returned string includes all characters after the first max - 1 returned strings (including separator characters).

 StringUtils.split(null, *, *)            = null
 StringUtils.split("", *, *)              = []
 StringUtils.split("ab de fg", null, 0)   = ["ab", "cd", "ef"]
 StringUtils.split("ab   de fg", null, 0) = ["ab", "cd", "ef"]
 StringUtils.split("ab:cd:ef", ":", 0)    = ["ab", "cd", "ef"]
 StringUtils.split("ab:cd:ef", ":", 2)    = ["ab", "cd:ef"]
 

参数:

str - the String to parse, may be null

separatorChars - the characters used as the delimiters, null splits on whitespace

max - the maximum number of elements to include in the array. A zero or negative value implies no limit

返回:

an array of parsed Strings, null if null String input

splitByWholeSeparator

public static String[] splitByWholeSeparator(String str,
                                             String separator)

Splits the provided text into an array, separator string specified.

The separator(s) will not be included in the returned String array. Adjacent separators are treated as one separator.

A null input String returns null. A null separator splits on whitespace.

 StringUtils.splitByWholeSeparator(null, *)               = null
 StringUtils.splitByWholeSeparator("", *)                 = []
 StringUtils.splitByWholeSeparator("ab de fg", null)      = ["ab", "de", "fg"]
 StringUtils.splitByWholeSeparator("ab   de fg", null)    = ["ab", "de", "fg"]
 StringUtils.splitByWholeSeparator("ab:cd:ef", ":")       = ["ab", "cd", "ef"]
 StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-") = ["ab", "cd", "ef"]
 

参数:

str - the String to parse, may be null

separator - String containing the String to be used as a delimiter, null splits on whitespace

返回:

an array of parsed Strings, null if null String was input

splitByWholeSeparator

public static String[] splitByWholeSeparator(String str,
                                             String separator,
                                             int max)

Splits the provided text into an array, separator string specified. Returns a maximum of max substrings.

The separator(s) will not be included in the returned String array. Adjacent separators are treated as one separator.

A null input String returns null. A null separator splits on whitespace.

 StringUtils.splitByWholeSeparator(null, *, *)               = null
 StringUtils.splitByWholeSeparator("", *, *)                 = []
 StringUtils.splitByWholeSeparator("ab de fg", null, 0)      = ["ab", "de", "fg"]
 StringUtils.splitByWholeSeparator("ab   de fg", null, 0)    = ["ab", "de", "fg"]
 StringUtils.splitByWholeSeparator("ab:cd:ef", ":", 2)       = ["ab", "cd:ef"]
 StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-", 5) = ["ab", "cd", "ef"]
 StringUtils.splitByWholeSeparator("ab-!-cd-!-ef", "-!-", 2) = ["ab", "cd-!-ef"]
 

参数:

str - the String to parse, may be null

separator - String containing the String to be used as a delimiter, null splits on whitespace

max - the maximum number of elements to include in the returned array. A zero or negative value implies no limit.

返回:

an array of parsed Strings, null if null String was input

splitByWholeSeparatorPreserveAllTokens

public static String[] splitByWholeSeparatorPreserveAllTokens(String str,
                                                              String separator)

Splits the provided text into an array, separator string specified.

The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. For more control over the split use the StrTokenizer class.

A null input String returns null. A null separator splits on whitespace.

 StringUtils.splitByWholeSeparatorPreserveAllTokens(null, *)               = null
 StringUtils.splitByWholeSeparatorPreserveAllTokens("", *)                 = []
 StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null)      = ["ab", "de", "fg"]
 StringUtils.splitByWholeSeparatorPreserveAllTokens("ab   de fg", null)    = ["ab", "", "", "de", "fg"]
 StringUtils.splitByWholeSeparatorPreserveAllTokens("ab:cd:ef", ":")       = ["ab", "cd", "ef"]
 StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-") = ["ab", "cd", "ef"]
 

参数:

str - the String to parse, may be null

separator - String containing the String to be used as a delimiter, null splits on whitespace

返回:

an array of parsed Strings, null if null String was input

从以下版本开始:

2.4

splitByWholeSeparatorPreserveAllTokens

public static String[] splitByWholeSeparatorPreserveAllTokens(String str,
                                                              String separator,
                                                              int max)

Splits the provided text into an array, separator string specified. Returns a maximum of max substrings.

The separator is not included in the returned String array. Adjacent separators are treated as separators for empty tokens. For more control over the split use the StrTokenizer class.

A null input String returns null. A null separator splits on whitespace.

 StringUtils.splitByWholeSeparatorPreserveAllTokens(null, *, *)               = null
 StringUtils.splitByWholeSeparatorPreserveAllTokens("", *, *)                 = []
 StringUtils.splitByWholeSeparatorPreserveAllTokens("ab de fg", null, 0)      = ["ab", "de", "fg"]
 StringUtils.splitByWholeSeparatorPreserveAllTokens("ab   de fg", null, 0)    = ["ab", "", "", "de", "fg"]
 StringUtils.splitByWholeSeparatorPreserveAllTokens("ab:cd:ef", ":", 2)       = ["ab", "cd:ef"]
 StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-", 5) = ["ab", "cd", "ef"]
 StringUtils.splitByWholeSeparatorPreserveAllTokens("ab-!-cd-!-ef", "-!-", 2) = ["ab", "cd-!-ef"]
 

参数:

str - the String to parse, may be null

separator - String containing the String to be used as a delimiter, null splits on whitespace

max - the maximum number of elements to include in the returned array. A zero or negative value implies no limit.

返回:

an array of parsed Strings, null if null String was input

从以下版本开始:

2.4