SpringBoot 使用WebSocket打造在线聊天室

1、WebSocket是HTML5开始提供的一种在单个 TCP 连接上进行全双工通讯的协议。在WebSocket API中，浏览器和服务器只需要做一个握手的动作，然后，浏览器和服务器之间就形成了一条快速通道。两者之间就直接可以数据互相传送。
2、浏览器通过 JavaScript 向服务器发出建立 WebSocket 连接的请求，连接建立以后，客户端和服务器端就可以通过 TCP 连接直接交换数据。
3、当你获取 Web Socket 连接后，你可以通过 send() 方法来向服务器发送数据，并通过 onmessage 事件来接收服务器返回的数据。

使用说明：

使用步骤：1、获取WebSocket客户端对象。

例如： var webSocket = new WebSocket(url);

使用步骤：2、获取WebSocket回调函数。

例如：webSocket.onmessage = function (event) {console.log('WebSocket收到消息：' + event.data);

事件类型	WebSocket回调函数	事件描述
open	webSocket.onopen	当打开连接后触发
message	webSocket.onmessage	当客户端接收服务端数据时触发
error	webSocket.onerror	当通信异常时触发
close	webSocket.onclose	当连接关闭时触发

使用步骤：3、发送消息给服务端

例如：webSokcet.send(jsonStr) 结合实际场景 本案例采用JSON字符串进行消息通信。

 

先引入websocket依赖

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<!-- websocket消息推送 --> <dependency>     <groupId>org.springframework.boot</groupId>     <artifactId>spring-boot-starter-websocket</artifactId> </dependency>

添加 WebSocketConfig 配置

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import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.socket.server.standard.ServerEndpointExporter; @Configuration public class WebSocketConfig {     @Bean     public ServerEndpointExporter serverEndpointExporter() {         return new ServerEndpointExporter();     }

实体bean接收客户端发过来的信息

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@Data public class SocketMsg {     /**      * 聊天类型 0 群聊 1 单聊      **/     private int type;     /**      * 发送者      **/     private String sendOutUser;     /**      * 接受者      **/     private String receiveUser;     /**      * 消息      **/     private String msg; }

WebSocketUtil

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import cn.hutool.json.JSONUtil; import org.springframework.stereotype.Component; import javax.websocket.*; import javax.websocket.server.PathParam; import javax.websocket.server.ServerEndpoint; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.CopyOnWriteArraySet; /**  * WebSocket 连接测试  */ @Component @ServerEndpoint("/web-socket/{userName}") public class WebSocketUtil {     private String userName;     private Session session;     /** 固定前缀  */     private static final String USER_NAME_PREFIX = "user_name_";     /**      * 用来存放每个客户端对应的MyWebSocket对象。      **/     private static CopyOnWriteArraySet<WebSocketUtil> webSocketSet = new CopyOnWriteArraySet<>();     /**      * 存放Session集合，方便推送消息 （javax.websocket.Session）      */     private static ConcurrentHashMap<String, Session> sessionMap = new ConcurrentHashMap<>();     /**      * 私聊：向指定客户端推送消息      */     public synchronized static void privateMessage(SocketMsg socketMsg) {         //接收消息的用户         Session receiveUser = sessionMap.get(USER_NAME_PREFIX + socketMsg.getReceiveUser());         //发送给接收者         if(receiveUser != null){             //发送给接收者             System.out.println(socketMsg.getSendOutUser()+" 向 "+socketMsg.getReceiveUser()+" 发送了一条消息："+socketMsg.getMsg());             receiveUser.getAsyncRemote().sendText(socketMsg.getSendOutUser()+"："+socketMsg.getMsg());         }else{             //发送消息的用户             System.out.println(socketMsg.getSendOutUser()+" 私聊的用户 "+socketMsg.getReceiveUser()+" 不在线或者输入的用户名不对");             Session sendOutUser = sessionMap.get(USER_NAME_PREFIX + socketMsg.getSendOutUser());             //将系统提示推送给发送者             sendOutUser.getAsyncRemote().sendText("系统消息：对方不在线或者您输入的用户名不对");         }     }     /**      * 群聊：公开聊天记录      * @param userName 发送者的用户名称（当前用户）      * @param message 发送的消息      * @param flag 用来标识 是否要将消息推送给 当前用户      */     public synchronized static void publicMessage(String userName,String message,boolean flag) {         for (WebSocketUtil item : webSocketSet) {             Session session = item.session;             if (flag){                 session.getAsyncRemote().sendText(message);             }else {                 //获取发送这条消息的用户                 Session currentUser = sessionMap.get(USER_NAME_PREFIX + userName);                 //消息不用推送到发送者的客户端                 if (!session.getId().equals(currentUser.getId())){                     session.getAsyncRemote().sendText(message);                 }             }         }         System.out.println("公共频道接收了一条消息："+message);     }     /**      * 监听：连接成功      * @param session      * @param userName 连接的用户名      */     @OnOpen     public void onOpen(Session session, @PathParam("userName") String userName) {         this.userName = userName;         this.session = session;         sessionMap.put(USER_NAME_PREFIX + userName, session);         webSocketSet.add(this);         //在线数加1         String tips = userName+" 加入聊天室。当前聊天室人数为" + webSocketSet.size();         System.out.println(tips);         publicMessage(userName,tips,true);     }     /**      * 监听：收到客户端发送的消息      * @param message 发送的信息（json格式，里面是 SocketMsg 的信息）      */     @OnMessage     public void onMessage(String message) {         if (JSONUtil.isTypeJSONObject(message)) {             SocketMsg socketMsg = JSONUtil.toBean(message, SocketMsg.class);             if(socketMsg.getType() == 1){                 //单聊，需要找到发送者和接受者                 privateMessage(socketMsg);             }else{                 //群发消息                 publicMessage(socketMsg.getSendOutUser(),socketMsg.getSendOutUser()+": "+socketMsg.getMsg(),false);             }         }     }     /**      * 监听: 连接关闭      */     @OnClose     public void onClose() {         if (sessionMap.containsKey(USER_NAME_PREFIX + userName)) {             //连接关闭后，将此websocket从set中删除             sessionMap.remove(USER_NAME_PREFIX + userName);             webSocketSet.remove(this);         }         String tips = userName+" 退出聊天室。当前聊天室人数为" + webSocketSet.size();         System.out.println(tips);         publicMessage(userName,tips,true);     }     /**      * 监听：发生异常      * @param error      */     @OnError     public void onError(Throwable error) {         System.out.println("userName为：" + userName + "，发生错误：" + error.getMessage());         error.printStackTrace();     } }

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<!DOCTYPE html> <html lang="en">     <head>         <meta charset="UTF-8">         <meta http-equiv="X-UA-Compatible" content="IE=edge">         <meta name="viewport" content="width=device-width, initial-scale=1.0">         <title>聊天室</title>         <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>         <style type="text/css">             input{                 width: 150px;                 height: 30px;                 line-height: 25px;                 padding: 5px 10px;                 border-radius: 5px;                 border: 2px solid;                 font-size: 16px;             }             #msg{                 width: 300px;             }             button{                 width: 80px;                 height: 44px;                 padding: 5px 20px;                 border-radius: 5px;             }         </style>     </head>     <body>         聊天室<br/><br/>         <input type="text" id="sendOutUser" placeholder="自己的用户名">         <button onclick="connectWebSocket()">上线</button>         <button onclick="closeWebSocket()">下线</button>         <br/><br>         <input type="text" id="msg" placeholder="要发送的信息"/>         <input type="text" id="receiveUser" placeholder="接收人的用户名"/>         <button onclick="send()">发送</button>         <br><br>         <hr>         <div id="msgList"></div>         <script type="text/javascript">             var websocket = null;             //连接WebSocket             function connectWebSocket() {                 var sendOutUser = document.getElementById("sendOutUser").value;                 if (sendOutUser === "") {                     alert("请输入用户名");                     return;                 }                 //判断当前浏览器是否支持websocket                 if ('WebSocket' in window) {                     websocket = new WebSocket("ws://localhost:7070/web-socket/"+document.getElementById("sendOutUser").value);                 } else {                     alert('当前浏览器 not support websocket')                 }                 //连接发生错误的回调方法                 websocket.onerror = function () {                     alert("连接发生错误");                 };                 //连接成功建立的回调方法                 websocket.onopen = function () {                     var sendOutUser = document.getElementById("sendOutUser")                     sendOutUser.readOnly = true                     sendOutUser.style.backgroundColor='#ddd'                 }                 //接收到消息的回调方法                 websocket.onmessage = function (event) {                     console.log(event.data)                     innerdiv("",event.data)                 }                 //连接关闭的回调方法                 websocket.onclose = function () {                     innerdiv("","websocket连接关闭");                 }                 //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。                 window.onbeforeunload = function () {                     closewebsocket();                 }             }             //关闭连接             function closeWebSocket() {                 websocket.close();             }             //发送消息             function send() {                 var m = new Map(); // 空Map                 var sendOutId = document.getElementById("sendOutUser")  //发送者                 var msg = document.getElementById("msg").value  //发送消息                 if (msg === "") {                     alert("请输入消息");                     return;                 }                 var receiveUser = document.getElementById("receiveUser").value //接收者                 m.set("sendOutUser",sendOutUser.value);                 m.set("msg",msg)                 // 接收者为空时，type为群聊，否则为私聊                 if (receiveUser === "") {                     m.set("type",0)                 }else{                     m.set("receiveUser",receiveUser)                     m.set("type",1)                 }                 json = mapToJson(m)                 websocket.send(json)                 innerdiv("我",msg)             }             //map转换为json             function  mapToJson(map) {                 var obj= Object.create(null);                 for (var[k,v] of map) {                     obj[k] = v;                 }                 return JSON.stringify(obj);             }             //显示聊天记录到页面             function innerdiv(id,txt){                 var msgList = document.getElementById("msgList")                 if (id === "") {                     msgList.innerHTML += "<div>" + txt + "</div><br>"                 }else{                     msgList.innerHTML += "<div>"+ id +": "+txt+ "</div><br>"                 }             }         </script>     </body> </html>