12. Android框架和工具之 StringUtils（字符串操作）

1. StringUtils介绍：

StringUtils是apache commons lang库（http://commons.apache.org/proper/commons-lang/download_lang.cgi)旗下的一个工具类，提供了很多有用的处理字符串的方法。

 关于StringUtils方法全集，可以看看这篇博客：http://blog.sina.com.cn/s/blog_4550f3ca0100qrsd.html

2. 这里我们主要介绍StringUtils常用的方法，如下：

（1）新建一个Java工程，如下：

（2）来到代码中，如下：

package com.himi.stringutils;

import org.apache.commons.lang3.StringUtils;

/**
 * StringUtils常用方法
 * 
 * @author hebao
 *
 */
public class StringUtilsTest {
    public static void main(String[] args) {

        /**
          * 检查字符串是否为空：
          *  static boolean isEmpty(CharSequence cs):判断字符串是否为空或null;
          *  static boolean isNotEmpty(CharSequence str):判断字符串是否非空或非null;
          *  
          *  static boolean isBlank(CharSequence str):判断字符串是否为空或null;
           *  static boolean isNotBlank(CharSequence str):判断字符串是否非空或非null;
          */
        String  str = "happy";
        System.out.println(StringUtils.isEmpty(str));//false
        System.out.println(StringUtils.isNotEmpty(str));//true
        System.out.println(StringUtils.isBlank(str));//false
        System.out.println(StringUtils.isNotBlank(str));//true
        
        
        /**
          * 清除字符串首尾空白字符：
          *  static String    trim(String str):清除掉str首尾的空白字符,str为空或者清除之后为空，return null
          *  static String    trimToEmpty(String str):清除掉str首尾的空白字符,str为空或者清除之后为空，return ""
          *  static String    trimToNull(String str):清除掉str首尾的空白字符,str为空或者清除之后为空，return ""
          *
          *  static String    strip(String str)：清除掉str首尾的空白字符
          *  static String    strip(String str, String stripChars)： 去掉 str 两端的在 stripChars中的字符
          *  static String[] stripAll(String... strs)：删除字符串数组strs中所有字符串元素首尾的空白字符
          *  static String[] stripAll(String[] strs, String stripChars)：去掉字符串数组strs中所有字符串元素首尾在 stripChars中的字符
          *  
          *  static String    stripEnd(String str, String stripChars)：去掉 str末尾的在 stripChars中的字符
          *  static String    stripStart(String str, String stripChars)：去掉 str首部的在 stripChars中的字符
          */
        String  str1 = "  !@ha32@@@prry! @$$ ";
        String  str2 = "ab23323232baewuyacb";
        String[] strs1 = new String[] {" abc ","aecwver89ewfac",
                "123321fsgreg"," 214g5499 0efw@#32"};
        System.out.println(StringUtils.trim(str1));//!@ha32@@@prry! @$$
        System.out.println(StringUtils.trimToEmpty(str1));//!@ha32@@@prry! @$$
        System.out.println(StringUtils.trimToNull(str1));//!@ha32@@@prry! @$$
        
        System.out.println(StringUtils.strip(str1));//!@ha32@@@prry! @$$
        System.out.println(StringUtils.strip(str2,"abc"));//23323232baewuy
        
        //[abc,aecwver89ewfac,123321fsgreg,214g5499 0efw@#32]
        System.out.println(printArray(StringUtils.stripAll(strs1)));
        //[,ecwver89ewf,fsgreg,4g5499 0efw@#]
        System.out.println(printArray(StringUtils.stripAll(strs1," abc123")));
        
        //ab23323232baewuy
        System.out.println(StringUtils.stripEnd(str2,"abc123"));
        //ewuyacb
        System.out.println(StringUtils.stripStart(str2,"abc123"));
        
        /**
          * 查找字符串是否包含其他字符：
          * 
          * 查找字符串seq中是否包含字符串searchSeq
          * static boolean    contains(CharSequence seq, CharSequence searchSeq)
          * 查找字符串seq中是否包含字符searchChar
          * static boolean    contains(CharSequence seq, int searchChar)
          * 
          * 查找字符串seq中是否包含任何在字符数组searchChars中的字符
          * static boolean    containsAny(CharSequence cs, char... searchChars)
          * 查找字符串seq中是否包含任何在字符串数组searchChars中的字符串
          * static boolean    containsAny(CharSequence cs, CharSequence... searchCharSequences)
          * 查找字符串seq中是否包含字符串searchChars
          * static boolean    containsAny(CharSequence cs, CharSequence searchChars)
          * 
          * 查找字符串seq中是否包含字符串searchChars，忽略大小写
          * static boolean    containsIgnoreCase(CharSequence str, CharSequence searchStr)
          * 
          * 查找字符串cs中是否不包含任何在字符数组searchChars中的字符
          * static boolean    containsNone(CharSequence cs, char... searchChars)
          * 查找字符串cs中是否不包含特定字符invalidChars(不能包含invalidChars任何字符)
          * static boolean    containsNone(CharSequence cs, String invalidChars)
          * 
          * 查找字符串cs中是否只是由字符数组valid中的字符组成的(不一定用到所有字符)
          * static boolean    containsOnly(CharSequence cs, char... valid)
          * static boolean    containsOnly(CharSequence cs, String validChars)
          * 
          * 查找字符串seq是否包含空格字符
          * static boolean    containsWhitespace(CharSequence seq)
          */
        
        
        
        /**
         * 比较两个字符串的不同：
         *  static String difference(String str1,String str2)：
         *  返回值：the portion of str2 where it differs from str1;
         */
        System.out.println(StringUtils.difference("", "abc"));//abc
        System.out.println(StringUtils.difference("ab", "abxyz"));//xyz
        System.out.println(StringUtils.difference("abcde", "xyz"));//xyz
        
        /**
         * 删除字符串中的所有空格：
         * static String deleteWhitespace(String str)
         */
        //0wfewfefwff88few
        System.out.println(StringUtils.deleteWhitespace("  0wfewf efwff88 few "));
    
        
        /**
         * 判断字符串的前缀：
         * static boolean startsWith(CharSequence str, CharSequence prefix)
         * static boolean startsWithAny(CharSequence string, CharSequence... searchStrings)
         * static boolean startsWithIgnoreCase(CharSequence str, CharSequence prefix)
         */
        System.out.println(StringUtils.startsWith("Img01.jpg","Img"));//true
        System.out.println(StringUtils.startsWithAny("abcxyz",
                new String[] {null, "xyz", "abc"}));//true
        
        /**
         * 判断字符串的后缀：
         * static boolean endsWith(CharSequence str, CharSequence suffix)
         * static boolean endsWithAny(CharSequence string, CharSequence... searchStrings)
         * static boolean endsWithIgnoreCase(CharSequence str, CharSequence suffix)
         */
        System.out.println(StringUtils.endsWith("fly.mp4",".mp4"));//true
        System.out.println(StringUtils.endsWithAny("abcxyz", new String[] {""}));//true
        System.out.println(StringUtils.endsWithAny("abcxyz",
                new String[] {null, "xyz", "abc"}));//true
        System.out.println(StringUtils.endsWith("fly.mp4",".MP4"));//false
        
        
        /**
         * 判断两个字符串的是否相等：
         * static boolean equals(CharSequence cs1, CharSequence cs2)
         * static boolean equalsIgnoreCase(CharSequence str1, CharSequence str2)
         */
        System.out.println(StringUtils.equals("AaBbCcDd","aabbccdd"));//false
        System.out.println(StringUtils.equalsIgnoreCase("AaBbCcDd","aabbccdd"));//true
        
        
        /**
         * 字符串的索引：
         * static int indexOf(CharSequence seq, CharSequence searchSeq)
         * static int indexOf(CharSequence seq, CharSequence searchSeq, int startPos)
         * static int indexOf(CharSequence seq, int searchChar)
         * static int indexOf(CharSequence seq, int searchChar, int startPos)
         * 
         * 搜索特定字符串在目标字符串CharSequence中首次出现的索引
         * static int indexOfAny(CharSequence cs, char... searchChars)
         * static int indexOfAny(CharSequence str, CharSequence... searchStrs)
         * static int indexOfAny(CharSequence cs, String searchChars)
         * 
         * static int indexOfIgnoreCase(CharSequence str, CharSequence searchStr)
         * static int indexOfIgnoreCase(CharSequence str, CharSequence searchStr, int startPos)
         * 
         */
        System.out.println(StringUtils.indexOf("abcdefg123rg","fg"));//5
        System.out.println(StringUtils.indexOf("abcdefg123rg",'e'));//4
        //System.out.println(StringUtils.indexOfAny("zzabyycdxx", "za"));//0
        System.out.println(StringUtils.indexOfAny("zzabyycdxx", "ab"));//2
        System.out.println(StringUtils.indexOfIgnoreCase("zzabyycdxx", "ZA"));//1
        
        
        /**
         * 检查字符串是否全是大写或者小写字符组成：
         * static boolean isAllLowerCase(CharSequence cs)
         * static boolean isAllUpperCase(CharSequence cs)
         */
        System.out.println(StringUtils.isAllUpperCase("ABCDEFG"));//true
        System.out.println(StringUtils.isAllLowerCase("AbCdEfG"));//false
        
        
        /**
         * 检查字符串是否是字符、字母、字母和数字组成的：
         * isAlpha(CharSequence cs)
         * isNumeric(CharSequence cs)
         * isAlphanumeric(CharSequence cs)
         */
        System.out.println(StringUtils.isAlpha("Afdasfdsf"));//true
        System.out.println(StringUtils.isNumeric("Afdasfdsf123123"));//false
        System.out.println(StringUtils.isAlphanumeric("Afdasfdsf123123"));//true
        
       /**
        * 方法用于把数组中的所有元素放入一个字符串。 元素是通过指定的分隔符进行分隔的：
        * static String    join(byte[] array, char separator)
        * static String    join(byte[] array, char separator, int startIndex, int endIndex)
        * static String    join(char[] array, char separator)
        * static String    join(char[] array, char separator, int startIndex, int endIndex)
        * static String    join(double[] array, char separator)
        * static String    join(double[] array, char separator, int startIndex, int endIndex)
        * ....
        * static String    join(Object[] array, char separator)
        * static String    join(Object[] array, char separator, int startIndex, int endIndex)
        * static String    join(Object[] array, String separator)
        * static String    join(Object[] array, String separator, int startIndex, int endIndex)
        * 
        */
        //ab;bde;23fe
        System.out.println(StringUtils.join(new String[]{"ab","bde","23fe"}, ';'));
        //12.45&23.4&45.3
        System.out.println(StringUtils.join(new float[]{12.45f,23.4f,45.3f}, '&'));
        
        
        
        /**
         * 去除字符串中特定字符 或者 字符串：
         * static String remove(String str, char remove)
         * static String remove(String str, String remove)
         * 
         * 如果str字符串末尾是remove字符串，就删除str末尾的remove，否则返回str
         * static String removeEnd(String str, String remove)
         * static String removeEndIgnoreCase(String str, String remove)
         * 
         * 如果str字符串开始是remove字符串，就删除str开始的remove，否则返回str
         * static String removeStart(String str, String remove)
         * static String removeStartIgnoreCase(String str, String remove)
         */
        //www.domain.com
        System.out.println(StringUtils.removeStart("www.domain.com", "domain"));
        //domain.com
        System.out.println(StringUtils.removeStart("www.domain.com", "www."));
        //www.domain.com
        System.out.println(StringUtils.removeEnd("www.domain.com", "domain"));
        //www.domain
        System.out.println(StringUtils.removeEnd("www.domain.com", ".com"));
        
        
        
        /**
         * 重复字符串次数:
         * static String repeat(char ch, int repeat)
         * static String repeat(String str, int repeat)
         */
        //LoveLoveLove
        System.out.println(StringUtils.repeat("Love", 3));
        
        
        
        /**
         * 字符串替换：
         * static String replace(String text, String searchString, String replacement)
         * 参数解析：
         * text---搜索的文本
         * searchString---在text文本中搜索的目标字符串searchString
         * replacement---用来替换searchString
         * 
         * static String replace(String text, String searchString, String replacement, int max)
         * static String replaceChars(String str, char searchChar, char replaceChar)
         * static String replaceChars(String str, String searchChars, String replaceChars)
         */
        //I ♥ YinChang
        System.out.println(StringUtils.replace("I Love YinChang", "Love","♥"));
        
        
        /**
         * 字符串的反转：
         * static String reverse(String str)
         * 
         */
        //I Love YinChang
        System.out.println(StringUtils.reverse("gnahCniY evoL I"));
        
        
        /**
         * 字符串分割成字符串数组：
         * static String[]    split(String str)//默认使用空格作为分离标记
         * static String[]    split(String str, char separatorChar)
         * static String[]    split(String str, String separatorChars)
         */
        //[HeBao,is,Good,Boy]
        System.out.println(printArray(StringUtils.split("HeBao is Good Boy")));
        //[HeBao,is,Good,Boy]
        System.out.println(printArray(StringUtils.split("HeBao#@is#@Good#@Boy","#@")));
    
    
        
        /**
         * 切割字符串：
         * static String substring(String str, int start)
         * 
         * start<= X <end
         * static String substring(String str, int start, int end)
         * 
         * 
         * static String substringAfter(String str, String separator)
         * 截取str中最后出现的分离符separator后面的字符串
         * static String substringAfterLast(String str, String separator)
         * 
         * 
         * static String substringBefore(String str, String separator)
         * 截取str中最后出现的分离符separator前面的字符串
         * static String substringBeforeLast(String str, String separator)
         * 
         * 
         * static String substringBetween(String str, String tag)
         * static String substringBetween(String str, String open, String close)
         * static String substringsBetween(String str, String open, String close)
         */
        //Love
        System.out.println(StringUtils.substring("hebaoLove",5));
        //hebao
        System.out.println(StringUtils.substring("hebaoLove",0,5));
        
        //Love
        System.out.println(StringUtils.substringAfter("hebaoLove","o"));
        //ve
        System.out.println(StringUtils.substringAfterLast("hebaoLove","o"));
        
        //abc
        System.out.println(StringUtils.substringBetween("tagabctag", "tag"));
        //abc
        System.out.println(StringUtils.substringBetween("yabczyabcz", "y", "z"));
    }
    
    public static  String printArray(String[] strs) {
        StringBuffer sb = new StringBuffer();
        sb.append("[");
        for(int i=0; i<strs.length; i++) {
            if(i==strs.length-1) {
                sb.append(strs[i]+"]");
                break;
            }
            sb.append(strs[i]+",");
        }
        
        return sb.toString();
        
    }

}