com.ctrip.framework.apollo.core.utils

类 StringUtils

java.lang.Object

com.ctrip.framework.apollo.core.utils.StringUtils

public class StringUtils
extends Object

嵌套类概要

嵌套类

限定符和类型	类和说明
static interface	StringUtils.StringFormatter<T>

字段概要

字段

限定符和类型	字段和说明
static String	EMPTY

构造器概要

构造器

构造器和说明
StringUtils()

方法概要

方法

限定符和类型	方法和说明
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 boolean	isBlank(String str) Checks if a String is whitespace, empty ("") or null.
static boolean	isContainEmpty(String... args)
static boolean	isEmpty(String str) Checks if a String is empty ("") or null.
static boolean	isNumeric(String str) Checks if the String contains only unicode digits.
static <T> String	join(Collection<T> collection, String separator)
static <T> String	join(Collection<T> collection, String separator, StringUtils.StringFormatter<T> formatter)
static boolean	startsWith(String str, String prefix) Check if a String starts with a specified prefix.
static boolean	startsWithIgnoreCase(String str, String prefix) Case insensitive check if a String starts with a specified prefix.
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

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

字段详细资料

EMPTY

public static final String EMPTY

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

isContainEmpty

public static boolean isContainEmpty(String... args)

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

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

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

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)

startsWith

public static boolean startsWith(String str,
                 String prefix)

Check if a String starts with a specified prefix.

nulls are handled without exceptions. Two null references are considered to be equal. The comparison is case sensitive.

 StringUtils.startsWith(null, null)      = true
 StringUtils.startsWith(null, "abc")     = false
 StringUtils.startsWith("abcdef", null)  = false
 StringUtils.startsWith("abcdef", "abc") = true
 StringUtils.startsWith("ABCDEF", "abc") = false
 

参数:

str - the String to check, may be null

prefix - the prefix to find, may be null

返回:

true if the String starts with the prefix, case sensitive, or both null

从以下版本开始:

2.4

另请参阅:

String.startsWith(String)

startsWithIgnoreCase

public static boolean startsWithIgnoreCase(String str,
                           String prefix)

Case insensitive check if a String starts with a specified prefix.

nulls are handled without exceptions. Two null references are considered to be equal. The comparison is case insensitive.

 StringUtils.startsWithIgnoreCase(null, null)      = true
 StringUtils.startsWithIgnoreCase(null, "abc")     = false
 StringUtils.startsWithIgnoreCase("abcdef", null)  = false
 StringUtils.startsWithIgnoreCase("abcdef", "abc") = true
 StringUtils.startsWithIgnoreCase("ABCDEF", "abc") = true
 

参数:

str - the String to check, may be null

prefix - the prefix to find, may be null

返回:

true if the String starts with the prefix, case insensitive, or both null

从以下版本开始:

2.4

另请参阅:

String.startsWith(String)

isNumeric

public static boolean isNumeric(String str)

Checks if the String contains only unicode digits. A decimal point is not a unicode digit and returns false.

null will return false. An empty String (length()=0) will return true.

 StringUtils.isNumeric(null)   = false
 StringUtils.isNumeric("")     = true
 StringUtils.isNumeric("  ")   = false
 StringUtils.isNumeric("123")  = true
 StringUtils.isNumeric("12 3") = false
 StringUtils.isNumeric("ab2c") = false
 StringUtils.isNumeric("12-3") = false
 StringUtils.isNumeric("12.3") = false
 

参数:

str - the String to check, may be null

返回:

true if only contains digits, and is non-null

join

public static <T> String join(Collection<T> collection,
              String separator)

join

public static <T> String join(Collection<T> collection,
              String separator,
              StringUtils.StringFormatter<T> formatter)