Java - WebSocket配置及使用

引入依赖

Spring Boot 默认支持 WebSocket，但需要引入 spring-boot-starter-websocket 依赖，然后重新构建项目

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

搭建 WebSocket 服务

创建 WebSocketServer.java

package com.project.module.webSocket;import com.fasterxml.jackson.databind.ObjectMapper;
import jakarta.websocket.*;
import jakarta.websocket.server.PathParam;
import jakarta.websocket.server.ServerEndpoint;
import org.springframework.stereotype.Service;import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;@Service
@ServerEndpoint("/ws/{userId}") // WebSocket 连接端点
public class WebSocketServer {// 存储所有用户的 WebSocket 连接private static final Map<String, WebSocketServer> clients = new ConcurrentHashMap<>();private Session session;private String userId; // 当前连接的用户ID@OnOpenpublic void onOpen(Session session, @PathParam("userId") String userId) {this.session = session;this.userId = userId;clients.put(userId, this);System.out.println("新客户端连接，当前在线用户：" + clients);}@OnMessagepublic void onMessage(String message) {System.out.println("收到消息：" + message);// 假设消息格式是 "userId:message"String[] parts = message.split(":", 2);if (parts.length == 2) {String targetUserId = parts[0];String msg = parts[1];sendToUser(targetUserId, "私信：" + msg);} else {System.out.println("无效的消息格式：" + message);}}//    @OnMessage
//    public void onMessage(String message, @PathParam("userId") String userId) {
//        System.out.println("收到消息：" + message);
//        sendToUser(userId, "私信：" + message);
//    }// 给指定用户发送消息public void sendToUser(String userId, Object messageObject) {WebSocketServer client = clients.get(userId);System.out.println("当前用户：" + userId);if (client != null) {try {// 使用 Jackson 转换对象为 JSONObjectMapper objectMapper = new ObjectMapper();String jsonMessage = objectMapper.writeValueAsString(messageObject);client.session.getBasicRemote().sendText(jsonMessage);} catch (IOException e) {e.printStackTrace();}} else {System.out.println("用户 " + userId + " 不在线，消息未发送");}}@OnClosepublic void onClose() {for (Map.Entry<String, WebSocketServer> entry : clients.entrySet()) {if (entry.getValue().session.getId().equals(session.getId())) {clients.remove(entry.getKey());System.out.println("客户端断开连接，当前在线人数：" + clients.size());break;}}}@OnErrorpublic void onError(Session session, Throwable error) {error.printStackTrace();}public void sendToAll(Object messageObject) {for (Map.Entry<String, WebSocketServer> entry : clients.entrySet()) {WebSocketServer client = entry.getValue();try {// 使用 Jackson 转换对象为 JSONObjectMapper objectMapper = new ObjectMapper();String jsonMessage = objectMapper.writeValueAsString(messageObject);client.session.getBasicRemote().sendText(jsonMessage);} catch (IOException e) {e.printStackTrace();}}}public Map<String, WebSocketServer> getClients() {return clients;}
}

手动注册 WebSocket

@ServerEndpoint 不能直接用 @Autowired 注入 Spring Bean，所以需要 手动注册
在 WebSocketConfig 里添加 Bean
创建 WebSocketConfig.java：

package com.project.module.webSocket;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import javax.websocket.server.ServerEndpointConfig;
import javax.websocket.server.ServerEndpointExporter;@Configuration
public class WebSocketConfig {// 启动 WebSocket 服务器@Beanpublic ServerEndpointExporter serverEndpointExporter() {return new ServerEndpointExporter();}
}

发送Websocket服务

package com.project.module.webSocket;import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;@Component
public class WebSocketTask {private final WebSocketServer webSocketServer;public WebSocketTask(WebSocketServer webSocketServer) {this.webSocketServer = webSocketServer;}// 每一分钟推送一次消息@Scheduled(fixedRate = 1000*60)public void pushMessage() {webSocketServer.sendToUser("userId","定时任务推送消息：" + System.currentTimeMillis());}
}

前端链接 WebSocket

创建 webSocket.js
注：此处的 import {host} from './base.js'为引入的全局服务地址，例如 host 为 localhost ，开发者可自行更换为自己的 WebSocket 地址

import {host} from './base.js'
const WebSocketService = {ws: null,connect(userId, callback) {this.ws = new WebSocket(`ws://${host}:8980/ws/` + userId);this.ws.onopen = () => {console.log("WebSocket 连接成功");};this.ws.onmessage = (event) => {callback(JSON.parse(event.data));};this.ws.onclose = () => {console.log("WebSocket 连接已关闭");};},sendMessage(message) {if (this.ws && this.ws.readyState === WebSocket.OPEN) {this.ws.send(message);}},disconnect() {if (this.ws) {this.ws.close();}},
};export default WebSocketService;

在Vue组将中使用

<template><div class="container"></div>
</template><script setup>
import { onMounted, ref } from "vue";
import WebSocketService from "@/utils/websocket";const CURRENT_CHART_NAME = 'safety'
const safetyRef = ref()
let safetyChart = nullconst { setChart } = useSetChart()onMounted(() => {websocketConn()
})function websocketConn() {const userId = `userId`WebSocketService.connect(userId, (msg) => {console.log(msg)});
}
</script>

注：此处的userId对应后端 webSocketServer.sendToUser("userId ","定时任务推送消息：" + System.currentTimeMillis()); 中的 userId,代表前端订阅WebSocket消息的用户以及WebSocket要发送的用户