项目总体结构图：
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>web</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
</welcome-file-list>
</web-app>
index.htm WS客户端
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>test ws</title>
</head>
<body>
Test ws
<script type="text/javascript">
//定义websocket
var ws = new WebSocket("ws://localhost:8080/web/websocket");
//连接websocket
ws.onopen = function()
{
var num = Math.ceil(Math.random()*100);
var msg = 'userid='+num;
console.log("open and send message："+msg);
// 发送消息
ws.send(msg);
};
//接收消息
ws.onmessage = function(evt)
{
console.log("get message:"+evt.data)
};
//关闭连接
ws.onclose = function(evt)
{
console.log("WebSocketClosed!");
};
//发生异常
ws.onerror = function(evt)
{
console.log("WebSocketError!");
};
</script>
</body>
</html>
SocketServer.java 核心类，WS服务端
1 package com.websocket; 2 3 import java.io.IOException; 4 import java.util.HashMap; 5 import java.util.Map; 6 import javax.websocket.OnClose; 7 import javax.websocket.OnError; 8 import javax.websocket.OnMessage; 9 import javax.websocket.OnOpen; 10 import javax.websocket.Session; 11 import javax.websocket.server.ServerEndpoint; 12 13 /** 14 * 环境 15 * 浏览器：firefox，google chrome 16 * tomcat7.0.69 17 * jdk7.0.79 18 * 1 每个浏览器代表一个用户，与服务端建立连接后，实现服务端与浏览器的交互 19 * 2 暴露websocket推送接口，其他服务端或者业务类调用该接口，向指定用户进行消息推送 20 * @author caihao 21 * 22 */ 23 //URI注解，无需在web.xml中配置。 24 @ServerEndpoint("/websocket") 25 public class SocketServer { 26 27 28 //浏览器与服务端的回话，浏览器每new一个WebSocket就创建一个session，关闭或刷新浏览器，session关闭 29 private Session session; 30 //代表浏览器 31 private String userid; 32 33 /** 34 * 推送消息接口 35 * 外部可以进行调用 36 * @param sendMsg 37 * @throws IOException 38 */ 39 public void sendMsg(String sendMsg) throws IOException{ 40 System.out.println(this.session+";"+this.userid+";"+sendMsg); 41 this.session.getBasicRemote().sendText(sendMsg); 42 } 43 44 //设置Map,存放每个用户的连接 45 public static Map<String,SocketServer> webSocketSet = new HashMap<String,SocketServer>(); 46 47 48 49 @OnOpen 50 public void onOpen(Session session) throws IOException { 51 this.session = session; 52 System.out.println(this+"有新连接,session="+session+";userid="+userid); 53 } 54 55 @OnClose 56 public void onClose() { 57 webSocketSet.remove(this.userid); 58 System.out.println(this+"；连接关闭"); 59 } 60 61 @OnMessage 62 public void onMessage(String info) throws IOException { 63 System.out.println(this+"；来自客户端的消息:" + info); 64 String msg = "服务端接收到了来自客户端的消息："+info; 65 if(info.contains("userid")){ 66 this.userid = info.split("userid=")[1]; 67 System.out.println(this+",this.session="+this.session+";this.userid="+this.userid); 68 webSocketSet.put(userid, this); 69 } 70 } 71 72 @OnError 73 public void onError(Throwable error) { 74 System.out.println(this+"；发生错误"); 75 error.printStackTrace(); 76 } 77 78 79 }
外部类，调用服务端的推送接口
1 package com.websocket; 2 3 import java.io.IOException; 4 import java.util.Map; 5 import javax.servlet.ServletException; 6 import javax.servlet.annotation.WebServlet; 7 import javax.servlet.http.HttpServlet; 8 import javax.servlet.http.HttpServletRequest; 9 import javax.servlet.http.HttpServletResponse; 10 11 /** 12 * 外部类，调用暴露的推送接口 13 */ 14 @WebServlet("/ServletA") 15 public class ServletA extends HttpServlet { 16 private static final long serialVersionUID = 1L; 17 18 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 19 this.doPost(request, response); 20 } 21 22 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 23 Map<String,SocketServer> webSocketSet = SocketServer.webSocketSet; 24 //遍历用户，依据用户的id向用户发送指定的内容 25 for(Map.Entry<String, SocketServer> entry:webSocketSet.entrySet()){ 26 System.out.println(entry.getKey()+"--->"+entry.getValue()); 27 String key = entry.getKey(); 28 SocketServer ss = webSocketSet.get(key); 29 String sendMsg = "向"+key+"发送消息"; 30 ss.sendMsg(sendMsg ); 31 } 32 33 } 34 }