java websocket心跳检测代码

以下是一个简单的Java WebSocket心跳检测代码示例，可以通过发送Ping消息并等待Pong响应来检测WebSocket连接是否仍然处于活动状态：

import java.net.URI;
import javax.websocket.ClientEndpoint;
import javax.websocket.CloseReason;
import javax.websocket.ContainerProvider;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.WebSocketContainer;

@ClientEndpoint
public class WebSocketClient {

    private Session session;

    @OnOpen
    public void onOpen(Session session) {
        this.session = session;
        System.out.println("WebSocket opened: " + session.getId());
        sendPing();
    }

    @OnMessage
    public void onMessage(String message) {
        if ("pong".equals(message)) {
            System.out.println("Received Pong: " + message);
            sendPing();
        } else {
            System.out.println("Received Message: " + message);
        }
    }

    @OnError
    public void onError(Throwable t) {
        System.err.println("WebSocket error: " + t.getMessage());
    }

    @OnClose
    public void onClose(Session session, CloseReason closeReason) {
        System.out.println("WebSocket closed with reason: " + closeReason.getReasonPhrase());
    }

    private void sendPing() {
        try {
            session.getBasicRemote().sendText("ping");
            System.out.println("Sent Ping: " + session.getId());
            Thread.sleep(5000); // Wait for Pong response
        } catch (Exception e) {
            System.err.println("Failed to send Ping: " + e.getMessage());
        }
    }

    public static void main(String[] args) {
        try {
            WebSocketContainer container = ContainerProvider.getWebSocketContainer();
            URI uri = new URI("ws://localhost:8080/endpoint");
            container.connectToServer(WebSocketClient.class, uri);
        } catch (Exception e) {
            System.err.println("Failed to connect to WebSocket server: " + e.getMessage());
        }
    }

}

在上面的代码中，onOpen()方法在WebSocket连接打开时发送第一个Ping消息。onMessage()方法接收来自服务器的消息，并根据接收到的消息类型进行处理。如果收到Pong响应，则发送另一个Ping消息。如果收到其他类型的消息，则将其打印到控制台上。

sendPing()方法使用session.getBasicRemote().sendText()发送Ping消息，并等待5000毫秒以等待Pong响应。如果在等待期间未收到Pong响应，则会捕获InterruptedException异常，并将错误消息打印到控制台上。

最后，在main()方法中，我们使用WebSocketContainer.connectToServer()方法连接到WebSocket服务器并启动客户端。请注意，URI参数应该是WebSocket服务器的端点地址。