流程分析

Websocket客户端与Websocket服务器端

 前端浏览器和后端服务器的连接通信

 HTTP与Websocket对比

服务器端编码

1.引入pom依赖

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

2. 编写配置类

@Configuration
public class WebSocketConfig
{@Beanpublic ServerEndpointExporter serverEndpointExporter(){return new ServerEndpointExporter();}
}

3.编写服务代码

import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;/*** WebSocket服务器设置*/
@ServerEndpoint(value = "/wsServer/{userId}")
@Component
public class WebSocketServer
{// concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。public static ConcurrentHashMap<String, WebSocketServer> webSocketMap = new ConcurrentHashMap<>();public static ConcurrentHashMap<String, WebSocketServer> typeMap = new ConcurrentHashMap<>();// 与某个客户端的连接会话，需要通过它来给客户端发送数据private Session session;// 接收userIdprivate String userId = "";/*** 连接建立成功调用的方法*/@OnOpenpublic void onOpen(Session session, @PathParam("userId") String userId){this.session = session;this.userId = userId;if (webSocketMap.containsKey(userId)){webSocketMap.remove(userId);webSocketMap.put(userId, this);} else{webSocketMap.put(userId, this);}try{sendMessage("我是服务端，你连接成功了！");} catch (IOException e){e.printStackTrace();}}/*** 连接关闭调用的方法*/@OnClosepublic void onClose(){if (webSocketMap.containsKey(userId)){webSocketMap.remove(userId);}}/*** 收到客户端消息后调用的方法*/@OnMessagepublic void onMessage(String message, Session session){if (StringUtils.isNotBlank(message)){try{// 解析发送的报文JSONObject jsonObject = JSON.parseObject(message);String type = (String) jsonObject.get("type");if (typeMap.containsKey(type)){typeMap.remove(type);typeMap.put(type, this);} else{typeMap.put(type, this);}} catch (Exception e){e.printStackTrace();}}}/*** 发生错误时调用*/@OnErrorpublic void onError(Session session, Throwable error){error.printStackTrace();}/*** 实现服务器主动推送*/public void sendMessage(String message) throws IOException{this.session.getBasicRemote().sendText(message);}/*** 发送自定义消息*/public static void sendInfo(String message, @PathParam("userId") String userId) throws IOException{if (StringUtils.isNotBlank(userId) && webSocketMap.containsKey(userId)){webSocketMap.get(userId).sendMessage(message);}}}

4.状态变更通知前端

// 通过WebSocket通知前端人员下发状态变更
try
{// 通过map获取对应的sessionWebSocketServer.typeMap.get("userId").sendMessage(封装的消息体);
} catch (IOException e)
{throw new RuntimeException(e);
}