websocket 概念websocket 是一个通信协议，通过单个 TCP 连接提供全双工通信。websocket 连接成功后，服务端和客户可以进行双向通信。不同于 http 通信协议需要每次由客户端发起，服务响应到客户端。websocket 相对轮询也能节约带宽，并且能实时的进行通信。整合步骤1. 添加 maven 依赖<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId></dependency><dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-websocket</artifactId> <version>2.1.3.RELEASE</version></dependency><dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-freemarker</artifactId> <version>2.1.3.RELEASE</version></dependency>添加web、websocket和freemarker依赖。2. 使用 ServerEndpointExporter 创建 bean这个 bean 会自动注册声明 @ServerEndpoint 注解声明的 websocket endpoint，使用springboot自带tomcat启动需要该配置，使用独立 tomcat 则不需要该配置。@Configurationpublic class WebSocketConfig { //tomcat启动无需该配置 @Bean public ServerEndpointExporter serverEndpointExporter() { return new ServerEndpointExporter(); }}3. 创建服务端端点 (ServerEndpoint)@Component@ServerEndpoint(value = "/message")@Slf4jpublic class WebSocket { private static Map<String, WebSocket> webSocketSet = new ConcurrentHashMap<>(); private Session session; @OnOpen public void onOpen(Session session) throws SocketException { this.session = session; webSocketSet.put(this.session.getId(),this); log.info("【websocket】有新的连接,总数:{}",webSocketSet.size()); } @OnClose public void onClose(){ String id = this.session.getId(); if (id != null){ webSocketSet.remove(id); log.info("【websocket】连接断开:总数:{}",webSocketSet.size()); } } @OnMessage public void onMessage(String message){ if (!message.equals("ping")){ log.info("【wesocket】收到客户端发送的消息,message={}",message); sendMessage(message); } } /** * 发送消息 * @param message * @return 全部都发送一遍 */ public void sendMessage(String message){ for (WebSocket webSocket : webSocketSet.values()) { webSocket.session.getAsyncRemote().sendText(message); } log.info("【wesocket】广播消息,message={}", message); }}4. 添加 controller 和 客户端添加 controller@GetMapping({"","index.html"})public ModelAndView index() { ModelAndView view = new ModelAndView("index"); return view;}添加ftl页面<!DOCTYPE html><html><head> <title>websocket</title></head><body><div> <input type="text" name="message" id="message"> <button id="sendBtn">发送</button></div><div style="width:100px;height: 500px;" id="content"></div><script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.0/jquery.js"></script><script type="text/javascript"> var ws = new WebSocket("ws://127.0.0.1:8080/message"); ws.onopen = function(evt) { console.log("Connection open ..."); }; ws.onmessage = function(evt) { console.log( "Received Message: " + evt.data); var p = $("<p>"+evt.data+"</p>") $("#content").prepend(p); $("#message").val(""); }; ws.onclose = function(evt) { console.log("Connection closed."); }; $("#sendBtn").click(function(){ var aa = $("#message").val(); ws.send(aa); })</script></body></html>5. 展示效果附录github源码
