websocket同步加心跳

import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;


/**
 * websocket推送
 *
 */
@ServerEndpoint("/websocket/{sid}")
@Component
@Slf4j
public class WebSocketServer {

    private static Logger log = LoggerFactory.getLogger(WebSocketServer.class);

    //静态变量，用来记录当前在线连接数。
    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>();

//    //心跳保活发送消息
//    private static final String HEARTBEAT_MESSAGE = "ping";
//
//    private ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();
//
//    private AtomicBoolean isAlive = new AtomicBoolean(true);

    //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sid
    private String sid="";

    /**
     * 连接建立成功调用的方法*/
    @OnOpen
    public void onOpen(Session session,@PathParam("sid") String sid) {
        this.session = session;
        webSocketSet.add(this);     //加入set中
        addOnlineCount();           //在线数加1
        log.info("有新窗口开始监听:"+sid+",当前在线人数为" + getOnlineCount());
        this.sid=sid;
        try {
            sendMessage("连接成功");
            //发送心跳
//            startHeartbeatTask();
        } catch (IOException e) {
           log.error("调用onOpen失败----------websocket IO异常");
        }
    }

    //心跳保活
//    private void startHeartbeatTask() {
//        scheduler.scheduleAtFixedRate(() -> {
//            if (isAlive.get() && session.isOpen()) {
//                try {
//                    sendMessage(HEARTBEAT_MESSAGE);
//                } catch (IOException e) {
//                    // 处理连接异常，可能需要关闭连接
//                    isAlive.set(false);
//                    try {
//                        session.close();
//                    } catch (IOException ex) {
//                        // 记录日志或执行其他清理操作
//                    }
//                }
//            }
//        }, 0, 5, TimeUnit.SECONDS);
//    }

    /**
     * 连接关闭调用的方法
     */
    @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());
    }

    /**
     * 收到客户端消息后调用的方法
     *
     * @param message 客户端发送过来的消息*/
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info("----收到来自窗口"+sid+"的信息 :"+message);
        //群发消息
        for (WebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                e.printStackTrace();
                log.error("调用onMessage失败----------websocket IO异常");
            }
        }
    }

    /**
     *
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
      log.error("发生错误");
      error.printStackTrace();
    }
    /**
     * 实现服务器主动推送
     */
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }

    /**
     * 群发自定义消息
     * */
    public static void sendInfo(String message,@PathParam("sid") String sid) throws IOException {
        log.info("推送消息到窗口"+sid+"，推送内容:"+message);
        for (WebSocketServer item : webSocketSet) {
            try {
                //这里可以设定只推送给这个sid的，为null则全部推送
                if(sid==null) {
                    item.sendMessage(message);
                }else if(item.sid.equals(sid)){
                    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--;
    }
}

依赖

<dependency>  
    <groupId>javax.websocket</groupId>  
    <artifactId>javax.websocket-api</artifactId>  
    <version>1.1</version>  
    <scope>provided</scope>  
</dependency>