java 正则表达式获取反向引用

package com.java.pattern;import java.util.regex.Matcher;import java.util.regex.Pattern;public class regTest {/** * @param args */public static void main(String[] args) {String regEx = "alias=\"(\\w*)\"";  String s = "alias=\"bbbb\"";                //忽略大小写Pattern pat = Pattern.compile(regEx,Pattern.CASE_INSENSITIVE); Matcher mat = pat.matcher(s);  boolean rs = mat.find();if(rs){//输出反向引用 bbbb，序号从1开始 group(0) 是匹配的字符串System.out.println(mat.group(1));}}}