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通配符^

^表示模式的开始,如^he匹配所有以he开头的字符串.
例程:
 String[] dataArr = { "he", "hero", "here", "hitler"};

    for (String str : dataArr) {
      String patternStr = "(^he)(\w*)";

      boolean result = Pattern.matches(patternStr, str);
      if (result) {
        System.out.println("字符串" + str + "匹配模式" + patternStr + "成功");
      } else {
        System.out.println("字符串" + str + "匹配模式" + patternStr + "失败");
      }
    }

通配符$

$表示模式的结束,如ia$匹配所有以ia结尾的单词.
 String[] dataArr = { "ia", "Asia", "China", "Colonbia","America"};

    for (String str : dataArr) {
      String patternStr = "(\w*)(ia$)";

      boolean result = Pattern.matches(patternStr, str);
      if (result) {
        System.out.println("字符串" + str + "匹配模式" + patternStr + "成功");
      } else {
        System.out.println("字符串" + str + "匹配模式" + patternStr + "失败");
      }
    }

通配符{}

除了用+表示一次或多次,*表示0次或多次,?表示0次或一次外,还可以用{}来指定精确指定出现的次数,X{2,5}表示X最少出现2次,最多出现5次;X{2,}表示X最少出现2次,多则不限;X{5}表示X只精确的出现5次.
例程:
String[] dataArr = { "google", "gooogle", "gooooogle", "goooooogle","ggle"};

for (String str : dataArr) {
 String patternStr = "g(o{2,5})gle";

 boolean result = Pattern.matches(patternStr, str);
 if (result) {
  System.out.println("字符串" + str + "匹配模式" + patternStr + "成功");
 } else {
  System.out.println("字符串" + str + "匹配模式" + patternStr + "失败");
 }
}

通配符[]中的-

-表示从..到…,如[a-e]等同于[abcde]
 String[] dataArr = { "Tan", "Tbn", "Tcn", "Ton","Twn"};

    for (String str : dataArr) {
      String regex = "T[a-c]n";

      boolean result = Pattern.matches(regex, str);
      if (result) {
        System.out.println("字符串" + str + "匹配模式" + regex + "成功");
      } else {
        System.out.println("字符串" + str + "匹配模式" + regex + "失败");
      }
    }

Pattern类的方法简述

模式类型Pattern.CASE_INSENSITIVE

正则表达式默认都是区分大小写的,使用了Pattern.CASE_INSENSITIVE则不对大小写进行区分.

 String patternStr="ab";
    Pattern pattern=Pattern.compile(patternStr, Pattern.CASE_INSENSITIVE);
   
    String[] dataArr = { "ab", "Ab", "AB"};
   
    for (String str : dataArr) {
      Matcher matcher=pattern.matcher(str);
     
      if(matcher.find()){
        System.out.println("字符串" + str + "匹配模式" + patternStr + "成功");
      }
    }

Pattern的split方法示例

 注意这里要把复杂的模式写在前面,否则简单模式会先匹配上.

String input="职务=GM 薪水=50000 , 姓名=职业经理人 ; 性别=男  年龄=45 ";
    String patternStr="(\s*,\s*)|(\s*;\s*)|(\s+)";
    Pattern pattern=Pattern.compile(patternStr);
   
    String[] dataArr=pattern.split(input);
   
    for (String str : dataArr) {
      System.out.println(str);
    }

Matcher类的方法简述

匹配示例一:XML元素文字解析

String regex="<(\w+)>(\w+)</\1>";
Pattern pattern=Pattern.compile(regex);
   
String input="<name>Bill</name><salary>50000</salary><title>GM</title>";
   
Matcher matcher=pattern.matcher(input);
   
while(matcher.find()){
      System.out.println(matcher.group(2));
}

替换实例一:将单词和数字部分的单词换成大写

    String regex="([a-zA-Z]+[0-9]+)";  
    Pattern pattern=Pattern.compile(regex);
   
    String input="age45 salary500000 50000 title";
   
    Matcher matcher=pattern.matcher(input);
   
    StringBuffer sb=new StringBuffer();
   
    while(matcher.find()){
      String replacement=matcher.group(1).toUpperCase();
      matcher.appendReplacement(sb, replacement);
    }
    matcher.appendTail(sb);
   
    System.out.println("替换完的字串为"+sb.toString());