icu.develop.expression.filter.utils

类 StringUtils

java.lang.Object

icu.develop.expression.filter.utils.StringUtils

public class StringUtils
extends Object

Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

作者:

Apache Software Foundation (ASF)

字段概要

字段

限定符和类型	字段和说明
static String	EMPTY The empty String "".
static String	SPACE A String for a space character.

构造器概要

构造器

限定符	构造器和说明
private	StringUtils()

方法概要

限定符和类型	方法和说明
static boolean	equals(CharSequence cs1, CharSequence cs2) Compares two CharSequences, returning true if they represent equal sequences of characters.
static boolean	isBlank(CharSequence cs) Checks if a CharSequence is empty (""), null or whitespace only.
static boolean	isEmpty(CharSequence cs) Checks if a CharSequence is empty ("") or null.
static boolean	isNotBlank(CharSequence cs) Checks if a CharSequence is not empty (""), not null and not whitespace only.
static boolean	isNumeric(CharSequence cs) Checks if the CharSequence contains only Unicode digits.
static boolean	regionMatches(CharSequence cs, boolean ignoreCase, int thisStart, CharSequence substring, int start, int length) Green implementation of regionMatches.

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

SPACE

public static final String SPACE

A String for a space character.

另请参阅:

常量字段值

EMPTY

public static final String EMPTY

The empty String "".

另请参阅:

常量字段值

构造器详细资料

StringUtils

private StringUtils()

方法详细资料

isEmpty

public static boolean isEmpty(CharSequence cs)

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

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

NOTE: This method changed in Lang version 2.0. It no longer trims the CharSequence. That functionality is available in isBlank().

参数:

cs - the CharSequence to check, may be null

返回:

true if the CharSequence is empty or null

isBlank

public static boolean isBlank(CharSequence cs)

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

Whitespace is defined by Character.isWhitespace(char).

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

参数:

cs - the CharSequence to check, may be null

返回:

true if the CharSequence is null, empty or whitespace only

isNotBlank

public static boolean isNotBlank(CharSequence cs)

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

Whitespace is defined by Character.isWhitespace(char).

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

参数:

cs - the CharSequence to check, may be null

返回:

true if the CharSequence is not empty and not null and not whitespace only

从以下版本开始:

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

equals

public static boolean equals(CharSequence cs1,
                             CharSequence cs2)

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
 

参数:

cs1 - the first CharSequence, may be null

cs2 - the second CharSequence, may be null

返回:

true if the CharSequences are equal (case-sensitive), or both null

从以下版本开始:

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

另请参阅:

Object.equals(Object)

regionMatches

public static boolean regionMatches(CharSequence cs,
                                    boolean ignoreCase,
                                    int thisStart,
                                    CharSequence substring,
                                    int start,
                                    int length)

Green implementation of regionMatches.

参数:

cs - the CharSequence to be processed

ignoreCase - whether or not to be case insensitive

thisStart - the index to start on the cs CharSequence

substring - the CharSequence to be looked for

start - the index to start on the substring CharSequence

length - character length of the region

返回:

whether the region matched

isNumeric

public static boolean isNumeric(CharSequence cs)

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

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

Note that the method does not allow for a leading sign, either positive or negative. Also, if a String passes the numeric test, it may still generate a NumberFormatException when parsed by Integer.parseInt or Long.parseLong, e.g. if the value is outside the range for int or long respectively.

 StringUtils.isNumeric(null)   = false
 StringUtils.isNumeric("")     = false
 StringUtils.isNumeric("  ")   = false
 StringUtils.isNumeric("123")  = true
 StringUtils.isNumeric("१२३")  = true
 StringUtils.isNumeric("12 3") = false
 StringUtils.isNumeric("ab2c") = false
 StringUtils.isNumeric("12-3") = false
 StringUtils.isNumeric("12.3") = false
 StringUtils.isNumeric("-123") = false
 StringUtils.isNumeric("+123") = false
 

参数:

cs - the CharSequence to check, may be null

返回:

true if only contains digits, and is non-null

从以下版本开始:

3.0 Changed signature from isNumeric(String) to isNumeric(CharSequence), 3.0 Changed "" to return false and not true