用AJAX写的聊天室（和淘宝下的阿里巴巴很像的工具条）
（例子见下面下载……）
1：页面
单击好友显示好友列表（这里是虚拟的），单击好友弹出对话框。

2 css样式


ChatServlet
package com.happysys.im;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class ChatServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request,response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//设置使用UTF-8字符集来解析请求参数//XMLHttpRequest所发送的POST请求默认采用UTF-8字符集        request.setCharacterEncoding("UTF-8");String msg = request.getParameter("chatMsg");System.out.println(msg);if ( msg != null &&  !msg.equals("")){//取得当前用户//String user = (String)request.getSession(true).getAttribute("user");String user=request.getParameter("user");//调用ChatService的addMsg来添加聊天消息ChatService.instance().addMsg(user , msg);System.out.println(user);}//设置响应内容的类型response.setContentType("text/html;charset=utf-8");//获取页面输出流PrintWriter out = response.getWriter();//直接生成响应out.println(ChatService.instance().getMsg());}}