一：创建maven webapp项目

编辑pom.xml文件

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">     <modelVersion>4.0.0</modelVersion>   <groupId>com.lala</groupId>   <artifactId>tweet</artifactId>   <version>1.0.0</version>   <packaging>war</packaging>     <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>    <jsp.version>2.2</jsp.version>    <jstl.version>1.2</jstl.version>    <servlet.version>3.0.1</servlet.version>    <spring-framework.version>4.1.7.RELEASE</spring-framework.version>    <junit.version>4.12</junit.version>   </properties>     <dependencies>    <dependency>     <groupId>org.springframework</groupId>     <artifactId>spring-webmvc</artifactId>     <version>${spring-framework.version}</version>    </dependency>    <dependency>     <groupId>javax.servlet</groupId>     <artifactId>jstl</artifactId>     <version>${jstl.version}</version>    </dependency>    <dependency>     <groupId>javax.servlet</groupId>     <artifactId>javax.servlet-api</artifactId>     <version>${servlet.version}</version>     <scope>provided</scope>    </dependency>    <dependency>     <groupId>javax.servlet.jsp</groupId>     <artifactId>jsp-api</artifactId>     <version>${jsp.version}</version>     <scope>provided</scope>    </dependency>    <dependency>     <groupId>junit</groupId>     <artifactId>junit</artifactId>     <version>${junit.version}</version>     <scope>test</scope>    </dependency>    <dependency>     <groupId>org.springframework</groupId>     <artifactId>spring-websocket</artifactId>     <version>${spring-framework.version}</version>    </dependency>    <dependency>     <groupId>com.google.code.gson</groupId>     <artifactId>gson</artifactId>     <version>2.3.1</version>    </dependency>   </dependencies>     <build>    <plugins>     <plugin>      <groupId>org.apache.maven.plugins</groupId>      <artifactId>maven-compiler-plugin</artifactId>      <version>3.3</version>      <configuration>       <source>1.8</source>       <target>1.8</target>       <verbose>true</verbose>      </configuration>     </plugin>     <plugin>      <groupId>org.eclipse.jetty</groupId>      <artifactId>jetty-maven-plugin</artifactId>      <version>9.2.11.v20150529</version>      <configuration>       <stopKey>foo</stopKey>       <stopPort>9999</stopPort>       <httpConnector>        <port>9090</port>       </httpConnector>       <webApp>        <contextPath>/</contextPath>       </webApp>      </configuration>     </plugin>    </plugins>   </build>    </project>

package com.lala.action;    import java.util.Map;  import java.util.concurrent.ConcurrentHashMap;    import org.springframework.web.socket.TextMessage;  import org.springframework.web.socket.WebSocketSession;  import org.springframework.web.socket.handler.TextWebSocketHandler;    import com.google.gson.Gson;    public class TweetWebSocket extends TextWebSocketHandler  {   private Map<String, WebSocketSession> clients = new ConcurrentHashMap<>();      public void handleTextMessage(WebSocketSession session, TextMessage message)   {    if(!clients.containsKey(session.getId()))    {     clients.put(session.getId(), session);    }    String data = message.getPayload();        Gson g = new Gson();    Map<String, Object> datas = g.fromJson(data, Map.class);    String type = datas.get("type").toString();        if("1".equals(type))    {     datas.put("pcount", clients.keySet().size() + "");    }    else if("3".equals(type))    {     clients.remove(session.getId());     datas.put("pcount", clients.keySet().size() + "");    }        TextMessage tm = new TextMessage(g.toJson(datas));    sendToAll(tm);   }   private void sendToAll(TextMessage tm)   {    try    {     for(WebSocketSession session : clients.values())     {      if(session.isOpen())      {       session.sendMessage(tm);      }      else      {       clients.remove(session.getId());      }     }    }catch(Exception e)    {     e.printStackTrace();    }   }  }

<?xml version="1.0" encoding="UTF-8"?>  <beans xmlns="http://www.springframework.org/schema/beans"          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"      xmlns:mvc="http://www.springframework.org/schema/mvc"       xmlns:context="http://www.springframework.org/schema/context"      xmlns:websocket="http://www.springframework.org/schema/websocket"      xsi:schemaLocation="http://www.springframework.org/schema/mvc       http://www.springframework.org/schema/mvc/spring-mvc.xsd      http://www.springframework.org/schema/beans       http://www.springframework.org/schema/beans/spring-beans.xsd      http://www.springframework.org/schema/websocket         http://www.springframework.org/schema/websocket/spring-websocket.xsd      http://www.springframework.org/schema/context       http://www.springframework.org/schema/context/spring-context.xsd">            <mvc:annotation-driven />            <context:component-scan base-package="com.lala"></context:component-scan>     <bean id="tweet" class="com.lala.action.TweetWebSocket"/>     <websocket:handlers>          <websocket:mapping path="/tweets/list" handler="tweet"/>      </websocket:handlers>     <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">          <property name="prefix" value="/WEB-INF/view/"/>          <property name="suffix" value=".jsp"/>   </bean>     </beans>

index.jsp页面

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>  <!DOCTYPE html>  <html>  <head>  <meta charset="utf-8" />  <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />  <title>动弹列表</title>  <script src="http://libs.baidu.com/jquery/1.9.0/jquery.js"></script>  <style type="text/css">   .jz {    margin: 0 auto;     text-align: center;   }   .tw {    border:1px dotted red;    height: 60px;    width:600px;    margin:0px auto;    padding-left:10px;    padding-top:10px;    margin-top:5px;   }   .top {       }   .buttom {    padding-top:10px;   }   #send-box {    margin-top:10px;   }  </style>  </head>  <body>  <div class="jz" style="font-size:30px;">动弹列表</div>  <div class="jz" style="font-size:20px;">欢迎回来：${param.username}，当前在线人数<b id="pcount"></b></div>  <div class="jz" id="err-box"></div>  <div id="msg-box">   <div class="tw">    <div class="top">admin  2015-07-05</div>    <div class="buttom">请大家随意畅谈</div>   </div>  </div>  <div id="send-box" class="jz">   <input type="text" id="text-msg" style="width:300px;"/>   <input type="button" onclick="send_msg()" value="发布动弹"/>  </div>  <script type="text/javascript">   var username = '${param.username}';   var ws = new WebSocket('ws://127.0.0.1:9090/tweets/list');     ws.onerror = function(event)   {    $('#err-box').html(event);   };     ws.onopen = function(event)    {    start() ;   };      ws.onclose = function(event) {     var msg = JSON.stringify({'username':username, 'type':'3'});      ws.send(msg);   };      ws.onmessage = function(event)    {    var data = JSON.parse(event.data);    if(data.type == '2')    {     render_data(data.username, data.data);    }    else if(data.type == '1')    {     $('#pcount').html(data.pcount);     render_data('<span style="color:red;">系统信息</span>', data.username + "加入系统");    }   };     function render_data(username, data)   {    var msg = [];    msg.push('<div class="tw">');    msg.push('<div class="top">' + username + '  2015-07-05</div>');    msg.push('<div class="buttom"> ' + data + ' </div>');    msg.push('</div>');    $('#msg-box').append(msg.join(''));   }      function start()    {    if(username != '')    {     var msg = JSON.stringify({'username':username, 'type':'1'});       ws.send(msg);    }   }     function send_msg()   {    var text_msg = $('#text-msg').val();    if(text_msg != '')    {     var msg = JSON.stringify({'username':username, 'type':'2', 'data': text_msg});       ws.send(msg);     $('#text-msg').val('');    }   }      (function(){    if(username == '')    {     alert('用户名为空，无法发布动弹');     $('#send-box').hide();    }   })();  </script>  </body>  </html>

最后，执行

mvn clean jetty:run

启动服务

在浏览器上面输入

http://127.0.0.1:9090/index.jsp?username=用户名

多开几个浏览器窗口，即可群聊