用例子来学习正则表达式

 
 

  
  
importjava.util.regex.Matcher;
  
  
importjava.util.regex.Pattern;
  
  

  
  

  
  

  
  
/**
  
  
*正则表达式：字符串的处理利器
  
  
*@authorkenan
  
  
*
  
  
*/
  
  
publicclassRegularExpressions{
  
  

  
  
publicstaticvoidmain(String[]args){
  
  
//在正则表达式中.代表一个字符
  
  
//System.out.println("abc".matches("..."));
  
  
//d代表一个数字:使用表达式进行匹配替换
  
  
//System.out.println("ab12356c".replaceAll("d","-"));
  
  
//这个是我们平时的用法
  
  
//System.out.println("ab12346c".replaceAll("123","---"));
  
  

  
  
//编译一个正则表达式
  
  
//Patternp=Pattern.compile("[a-z]{3}");
  
  
//匹配一个字符串，返回一个Matcher对象
  
  
//Matcherm=p.matcher("abc");
  
  
//System.out.println(m.matches());
  
  

  
  
//.:一个字符
  
  
//*:0或多个字符
  
  
//+:1或者多个
  
  
//？：0或者1个
  
  
//System.out.println("a".matches("."));
  
  
//System.out.println("aa".matches("aa"));
  
  
//System.out.println("aaaa".matches("a*"));
  
  
//System.out.println("".matches("a*"));
  
  
//System.out.println("aaa".matches("a?"));
  
  
//System.out.println("".matches("a?"));
  
  
//System.out.println("a".matches("a?"));
  
  
//System.out.println("123456".matches("d{3,100}"));
  
  
//System.out.println("12".matches("d{3,100}"));
  
  
//System.out.println("192.168.0.aaa".matches("d{1,3}.d{1,3}"));
  
  
//System.out.println("192.168.0.2".matches("d{1,3}"));
  
  
//System.out.println("192".matches("[0-2][0-9][0-9]"));
  
  
//System.out.println("192".matches("[0-9]"));
  
  

  
  
//范围匹配
  
  
//System.out.println("a".matches("[abc]"));
  
  
//System.out.println("a".matches("[^abc]"));
  
  
//System.out.println("A".matches("[a-zA-Z1-9]"));
  
  
//System.out.println("3".matches("[a-zA-Z1-9]"));
  
  
//System.out.println("A".matches("[a-z]|[A-Z]"));
  
  
//System.out.println("R".matches("[A-Z&&[RFG]]"));
  
  

  
  

  
  
//认识swd
  
  
//d一个数字[0-9]
  
  
//D上面取反
  
  
//s一个空字符[tnrfx0B]
  
  
//S上面取反
  
  
//w一个字符[a-zA-Z_0-9]
  
  
//W出了上面的字符以为的其他字符
  
  
//代表一个
  
  
//System.out.println("nrt".matches("s{1,4}"));
  
  
//System.out.println("".matches("S"));
  
  
//System.out.println("a_8".matches("w{1,3}"));
  
  
//System.out.println("abc888&^%".matches("[a-z]{1,3}d+[&^#%]+"));
  
  
//System.out.println("".matches("\"));
  
  

  
  

  
  
//PosixStyle
  
  
//System.out.println("a".matches("p{Lower}"));
  
  

  
  
//边界处理
  
  
//^在[]里代表取反在外面代表字符开头
  
  
//$代表以什么结尾
  
  
//b代表单词结束
  
  
//System.out.println("hellosir".matches("^h.*"));
  
  
//System.out.println("hellosir".matches(".*ir$"));
  
  
//System.out.println("hellosirr".matches(".*ir$"));
  
  
//System.out.println("hellosir".matches("^h[a-z]{1,3}ob.*"));
  
  
//System.out.println("hellosir".matches("^h[a-z]{1,3}ob.*"));
  
  
//System.out.println("hellosir".matches("^h[a-z]{1,3}ob.*"));
  
  
//System.out.println("hello&sir".matches("^h[a-z]{1,3}ob.*"));
  
  
//System.out.println("hello.sir".matches("^h[a-z]{1,3}ob.*"));
  
  

  
  
//找出空白行
  
  
//System.out.println("n".matches("^[s&&[^n]]*n$"));
  
  
//System.out.println("n".matches("^[s&&[^n]]*n$"));
  
  

  
  
//email
  
  
//System.out.println("soukenan@qq.com".matches("[w.-]+@[w.-]+.[w]+"));
  
  

  
  
//matchesfromlookingat
  
  

  
  
//Patternp=Pattern.compile("d{3,5}");
  
  
//Strings="123-45674-234-00";
  
  
//Matcherm=p.matcher(s);
  
  
//System.out.println(m.matches());//false//从前往后匹配
  
  
//m.reset();//把光标重置
  
  
//System.out.println(m.find());//true//从当前的标志开始查找
  
  
//System.out.println(m.start()+":"+m.end());
  
  
//System.out.println(m.find());//true查找匹配的字串
  
  
//System.out.println(m.start()+":"+m.end());
  
  
//System.out.println(m.find());//true
  
  
//System.out.println(m.start()+":"+m.end());
  
  
//System.out.println(m.find());//false
  
  
//
  
  
//System.out.println(m.lookingAt());//true//从头开始看看是否匹配
  
  
//System.out.println(m.lookingAt());//true
  
  
//System.out.println(m.lookingAt());//true
  
  
//System.out.println(m.lookingAt());//true
  
  

  
  

  
  
//replacement字符串的替换
  
  
//Patternp=null;
  
  
//p=Pattern.compile("java");
  
  
//p=Pattern.compile("java",Pattern.CASE_INSENSITIVE);//忽略大小写
  
  
//Matcherm=p.matcher("javaJavaJaVajavA,iloveJAVA!");
  
  
//while(m.find()){
  
  
//System.out.println(m.group());
  
  
//}
  
  
//System.out.println(m.replaceAll("JAVA"));//把找到的匹配字符串转换成JAVA
  
  
//StringBufferbuf=newStringBuffer();
  
  
//inti=0;
  
  
//while(m.find()){
  
  
//i++;
  
  
//if(i%2==0){
  
  
//m.appendReplacement(buf,"java");//偶数转换成java
  
  
//}else{
  
  
//m.appendReplacement(buf,"JAVA");//奇数转换成JAVA
  
  
//}
  
  
//}
  
  
//m.appendTail(buf);//把尾部字符串添加上去
  
  
//System.out.println(buf);
  
  

  
  
//group分组
  
  
//()这个是用来分组的
  
  
Patternp=Pattern.compile("(d{3,5})([a-z]{2})");
  
  
Strings="123aa-3456bb-234cc-00";
  
  
Matcherm=p.matcher(s);
  
  
while(m.find()){
  
  
System.out.println(m.group(1)+":"+m.group(2));
  
  
}
  
  

  
  

  
  
}
  
  

  
  
}
 
 

（编辑：李大同）

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