利用spring boot+WebSocket实现后台主动消息推送功能

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

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

package com.star.manager.service;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArraySet;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
@Slf4j
//@ServerEndpoint("/websocket/{user}")
@ServerEndpoint(value = "/websocket")
@Component
public class WebSocketServer {
    //静态变量，用来记录当前在线连接数。应该把它设计成线程安全的。
    private static int onlineCount = 0;
    //concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。
    private static CopyOnWriteArraySet<WebSocketServer> webSocketSet = new CopyOnWriteArraySet<WebSocketServer>();
    //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;
    
    @OnOpen
    public void onOpen(Session session) {
        this.session = session;
        webSocketSet.add(this);     //加入set中
        addOnlineCount();           //在线数加1
        log.info("有新连接加入！当前在线人数为" + getOnlineCount());
        try {
             sendMessage("连接成功");
        } catch (IOException e) {
            log.error("websocket IO异常");
        }
    }
    //    //连接打开时执行
    //    @OnOpen
    //    public void onOpen(@PathParam("user") String user, Session session) {
    //        currentUser = user;
    //        System.out.println("Connected ... " + session.getId());
    //    }
 
    
    @OnClose
    public void onClose() {
        webSocketSet.remove(this);  //从set中删除
        subOnlineCount();           //在线数减1
        log.info("有一连接关闭！当前在线人数为" + getOnlineCount());
    }
 
    
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info("来自客户端的消息:" + message);
 
        //群发消息
        for (WebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
 
    
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("发生错误");
        error.printStackTrace();
    }
 
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }
 
    
    public static void sendInfo(String message) throws IOException {
        log.info(message);
        for (WebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                continue;
            }
        }
    }
 
    public static synchronized int getOnlineCount() {
        return onlineCount;
    }
 
    public static synchronized void addOnlineCount() {
        WebSocketServer.onlineCount++;
    }
 
    public static synchronized void subOnlineCount() {
        WebSocketServer.onlineCount--;
    }
}

     @RequestMapping(value="/pushVideoListToWeb",method=RequestMethod.POST,consumes = "application/JSON")
     public @ResponseBody Map<String,Object> pushVideoListToWeb(@RequestBody Map<String,Object> param) {
         Map<String,Object> result =new HashMap<String,Object>();
         try {
             WebSocketServer.sendInfo("有新客户呼入,sltAccountId:"+CommonUtils.getValue(param, "sltAccountId"));
             result.put("operationResult", true);
         }catch (IOException e) {
             result.put("operationResult", true);
         }
         return result;
     }

    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }

//socket = new WebSocket("ws://localhost:9094/starManager/websocket/张三");
        var socket;
        if(typeof(WebSocket) == "undefined") {
            console.log("您的浏览器不支持WebSocket");
        }else{
            console.log("您的浏览器支持WebSocket");
            
            //实现化WebSocket对象，指定要连接的服务器地址与端口  建立连接
            //socket = new WebSocket("ws://localhost:9094/starManager/websocket/张三")

            socket = new WebSocket("ws://localhost:9094/starManager/websocket");
            //打开事件
            socket.onopen = function() {
                console.log("Socket 已打开");
                //socket.send("这是来自客户端的消息" + location.href + new Date());
            };
            //获得消息事件
            socket.onmessage = function(msg) {
                console.log(msg.data);
                //发现消息进入    调后台获取
                getCallingList();
            };
            //关闭事件
            socket.onclose = function() {
                console.log("Socket已关闭");
            };
            //发生了错误事件
            socket.onerror = function() {
                alert("Socket发生了错误");
            }
             $(window).unload(function(){
                  socket.close();
                });
 
//                                    $("#btnSend").click(function() {
//                                        socket.send("这是来自客户端的消息" + location.href + new Date());
//                                    });
//
//                                    $("#btnClose").click(function() {
//                                        socket.close();
//                                    });
        }

socket = new WebSocket("ws://localhost:9094/starManager/websocket");