public static void main(String[] args) {
    //被替换关键字的的数据源
    Map tokens = new HashMap();
    tokens.put("cat", "Garfield");
    tokens.put("beverage", "coffee");

    //匹配类似velocity规则的字符串
    String template = "${cat} really needs some ${beverage}.";
    //生成匹配模式的正则表达式
    String patternString = "\$\{(" + StringUtils.join(tokens.keySet(), "|") + ")\}";

    Pattern pattern = Pattern.compile(patternString);
    Matcher matcher = pattern.matcher(template);

    //两个方法：appendReplacement, appendTail
    StringBuffer sb = new StringBuffer();
    while(matcher.find()) {
        matcher.appendReplacement(sb, tokens.get(matcher.group(1)));
    }
    matcher.appendTail(sb);

    //out: Garfield really needs some coffee.
    System.out.println(sb.toString());

    //对于特殊含义字符"","$"，使用Matcher.quoteReplacement消除特殊意义
    matcher.reset();
    //out: cat really needs some beverage.
    System.out.println(matcher.replaceAll("$1"));
    //out: $1 really needs some $1.
    System.out.println(matcher.replaceAll(Matcher.quoteReplacement("$1")));

    //到得邮箱的前缀名。插一句，其实验证邮箱的正则多种多样，根据自己的需求写对应的正则才是王道
    String emailPattern = "^([a-z0-9_\.\-\+]+)@([\da-z\.\-]+)\.([a-z\.]{2,6})$";
    pattern = Pattern.compile(emailPattern);
    matcher = pattern.matcher("test@qq.com");
    //验证是否邮箱
    System.out.println(matcher.find());
    //得到@符号前的邮箱名  out: test
    System.out.println(matcher.replaceAll("$1"));

    //获得匹配值
    String temp = "";
    pattern = Pattern.compile("android:(name|value)="(.+?)"");
    matcher = pattern.matcher(temp);
    while(matcher.find()) {
        //out: appid, joy
        System.out.println(matcher.group(2));
    }
}