类似于velocity的正则匹配

public static void main(String[] args) {
		
		Map<String,String> tokens = new HashMap<String,String>();

		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(), "|") + ")\\}";
		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("[e-mail]");
		//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 = "<meta-data android:name=\"appid\" android:value=\"joy\"></meta-data>";
		pattern = Pattern.compile("android:(name|value)=\"(.+?)\"");
		matcher = pattern.matcher(temp);
		while(matcher.find()) {
			//out: appid, joy
			System.out.println(matcher.group(2));
			}
		}