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));
		}
	}
}