java常用API

package com.orcal.demc01;

public class Regex2 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		//将符合规则的字符串内容，全部替换为新字符串
		//将a替换成b
       String str="java ai wo,wo ai java";
       String regex="a";
       String s=str.replaceAll(regex, "b");
       System.out.println(s);
       //	匹配合法的邮箱
       //+是出现一次或多次
       String regex1="[a-zA-Z0-9]+@[a-zA-z0-9]+\.[a-zA-Z]+";
       String str1="1051765559@qq.com";
       boolean f=str1.matches(regex1);
       System.out.println(f);
     
       String regex2=".+";
       String str2="1051765559@qq.com";
       boolean f2=str2.matches(regex1);
       System.out.println(f);
       //获取IP地址(192.168.1.100)中的每段数字	   
       String regex3="[0-9]{3}\.[0-9]{3}\.[0-9]{1,3}\.[0-9]{3}";
       String str3="192.168.52.165";
       boolean f3=str3.matches(regex3);
       System.out.println(f3);
	
	}
}