正则表达式 - Cirry's Blog

认识正则表达式

范例：简单的字符串验证

1
package cn.cccc.demo;
2
public class Demo {
3
    public static void main(String[] args) {
4
       // TODO Auto-generated method stub
5
       String str = "123456";
6
       if(isNumber(str)){
7
           int num = Integer.parseInt(str);
8
           System.out.println(num*2);
9
       }
10
    }
11

12
    public static boolean isNumber(String  str){
13
       char data [] = str.toCharArray();
14
       for(int x= 0 ; x < data.length ;  x++){
15
           if(data[x] > '9' && data[x] <  '0'){
6 collapsed lines
16
               return false;
17
           }
18
       }
19
       return true;
20
    }
21
}

用正则实现同样的功能

1
package cn.cccc.demo;
2
public class Demo {
3
    public static void main(String[] args) {
4
       // TODO Auto-generated method stub
5
       String str = "123456";
6
       if(str.matches("\\d+")){
7
           int num = Integer.parseInt(str);
8
           System.out.println(num*2);
9
       }
10
    }
11
}

范例：实现字符串替换（删除掉非字母与数字）

1
package cn.cccc.demo;
2
public class Demo {
3
    public static void main(String[] args) {
4
       // TODO Auto-genera4ted method stub
5
       String str =  "1uio4321jd%^sa*4321(sjiod431g541541h431iajj4diud43434321saD";
6
       String regex = "[^a-zA-Z0-9]+";
7
       System.out.println(str.replaceAll(regex,""));
8
    }
9
}