求处理含有占位符（Placeholder）的字符串的工具类库！

本人想未来把自己的产品进行国际化，所以把程序给外部系统做出的所有提示信息都存放到文件messages.properties。
Example:
messages.properties

web.services.members.response.msg.notfound=\u5bf9\u4e0d\u8d77\uff0c\u6ca1\u6709\u53d1\u73b0\u4e0e[${username}]\u76f8\u5339\u914d\u7528\u6237\uff01

web.services.members.response.msg.found=\u5171\u627e\u5230\u4e0e[${username}]\u76f8\u5339\u914d\u7684\u7528\u6237${count}\u4e2a\uff01

web.services.members.response.msg.exception=\u670d\u52a1\u5668\u51fa\u73b0\u5f02\u5e38\uff0c\u8bf7\u7a0d\u540e\u518d\u8bd5\uff01

web.services.members.response.msg.error=\u670d\u52a1\u5668\u51fa\u73b0\u5185\u90e8\u9519\u8bef\uff01

messages.properties实际内容如下：
web.services.members.response.msg.notfound=没有发现与[${username}]相匹配用户！
web.services.members.response.msg.found=共找到与[${username}]相匹配的用户${count}个！
web.services.members.response.msg.exception=服务器出现异常，请稍后再试！
web.services.members.response.msg.error=服务器出现内部错误！

稍后，我新创建一个类MessageBundle：

package com.dongantech.eshop.web.util;



import java.util.*;

import java.io.*;



public class MessageBundle {

	public static Properties PROPS = null ;

	

	private Map bundle =  null;

	

	static {

		InputStream propertiesInputStream = MessageBundle.class.getResourceAsStream("/messages.properties");

		PROPS = new Properties();

		try {

			PROPS.load(propertiesInputStream);

		} catch (IOException e) {

			e.printStackTrace();

		}

	}

	public MessageBundle(){

		bundle = new HashMap();

	}

	public void setBundle(Map theBundle){

		bundle = theBundle;

	}

	public Map getBundle(){

		return bundle ;

	}

	public String getMessage(String theMsgKey){

		return (String)bundle.get(theMsgKey);

	}

	public void putIntoBundle(String theMsgKey){

		String msgFrame = MessageBundle.PROPS.getProperty(theMsgKey);

		bundle.put(theMsgKey,msgFrame);

	}

}

这样，我的Servlet就自己去打包所需要的信息成一个MessageBundle对象，由于信息反馈对于系统来说是很频繁的活动，如果每一个这样的对象（Servlet）都包含一个MessageBundle对象，就会避免了多个Servlet间对某信息集合对象（使用单例模式方式）请求占用所带来的执行延时。

public class MemberManagerServlet extends HttpServlet{

	public static final String MSG_KEY_NOT_FOUND = "web.services.members.response.msg.notfound" ; 

	public static final String MSG_KEY_FOUND = "web.services.members.response.msg.found" ;

	public static final String MSG_KEY_EXCEPTION = "web.services.members.response.msg.exception" ;

	public static final String MSG_KEY_ERROR = "web.services.members.response.msg.error" ;

	

	private Map requestHandlers = null ;

	private PageLocator pageLocator = null ;

	private MessageBundle messageBundle = null ;

	

	public MemberManagerServlet(){

		requestHandlers = new HashMap();

		pageLocator = new PageLocator();

		

		pageLocator.registerPage(SimpleResponse.TYPE_FOUND,MemberManagerServlet.PAGE_FOUND );

		pageLocator.registerPage(SimpleResponse.TYPE_NOT_FOUND,MemberManagerServlet.PAGE_NOT_FOUND);

		pageLocator.registerPage(SimpleResponse.TYPE_EXCEPTION,MemberManagerServlet.PAGE_EXCEPTION);

		pageLocator.registerPage(SimpleResponse.TYPE_ERROR,MemberManagerServlet.PAGE_ERROR);

		

		messageBundle.putIntoBundle(MemberManagerServlet.MSG_KEY_NOT_FOUND);

		messageBundle.putIntoBundle(MemberManagerServlet.MSG_KEY_FOUND);

		messageBundle.putIntoBundle(MemberManagerServlet.MSG_KEY_EXCEPTION);

		messageBundle.putIntoBundle(MemberManagerServlet.MSG_KEY_ERROR);

	}

	public void init(ServletConfig config){

		try {

			super.init(config);

		} catch (ServletException e) {

			e.printStackTrace();

		}

	}

	public void doGet(HttpServletRequest httpReq,HttpServletResponse httpResp){

		Response response = processRequest(httpReq,httpResp);

		try {

			deliver(response);

		} catch (Exception e) {

			e.printStackTrace();

		}

	}

	

	public void doPost(HttpServletRequest httpReq,HttpServletResponse httpResp){

		Response response = processRequest(httpReq,httpResp);

		try {

			deliver(response);

		} catch (Exception e) {

			e.printStackTrace();

		}

	}

	

	public Response processRequest(HttpServletRequest httpReq,HttpServletResponse httpResp){

		Response response = null ;

		String handlerName = httpReq.getParameter("request");

		RequestHandler handler = getHandler(handlerName);

		Request request = buildRequest(httpReq);

		try {

			response = handler.process(request);

			response.getContext().put("page",getPage(response.getType()));

		} catch (Exception e) {

			response = new SimpleResponse(SimpleResponse.TYPE_ERROR);

			e.printStackTrace();

		}

		return response ;

	}



}

接下来，我就不晓得使用什么工具类库（Util Lib）来处理含有占位符的字符串了。因为没有用过。大家帮我推荐个～谢谢！
不好意思，比较啰嗦～只想分享一下设计心得～