java正则表达式

import java.util.regex.Matcher;import java.util.regex.Pattern;public class RegTest{    public static void  main(String []a){        Pattern pattern=Pattern.compile("(\\d{1,8})@(\\w{1,5}).(\\w{1,5})");        Matcher matcher=pattern.matcher("[e-mail]");        if (matcher.find()){            System.out.println(matcher.group());            System.out.println(matcher.group(1));            System.out.println(matcher.group(2));            System.out.println(matcher.group(3));        }    }}输出结果:[e-mail]123123qqcom