import java.net.URI;
import java.net.URISyntaxException;
import java.util.Timer;
import java.util.TimerTask;

import org.java_websocket.client.WebSocketClient;
import org.java_websocket.handshake.ServerHandshake;

public class HeartbeatWebSocketClient extends WebSocketClient {

    private Timer heartbeatTimer;
    private boolean isClosed;

    public HeartbeatWebSocketClient(URI serverUri) {
        super(serverUri);
        this.isClosed = false;
    }

    @Override
    public void onOpen(ServerHandshake handshakedata) {
        // 連接建立成功，啟動(dòng)心跳定時(shí)器
        this.startHeartbeat();
    }

    @Override
    public void onClose(int code, String reason, boolean remote) {
        // 連接關(guān)閉，停止心跳定時(shí)器
        this.stopHeartbeat();
        this.isClosed = true;
    }

    @Override
    public void onError(Exception ex) {
        // 發(fā)生異常，停止心跳定時(shí)器
        this.stopHeartbeat();
    }

    private void startHeartbeat() {
        // 啟動(dòng)心跳定時(shí)器，每隔30秒發(fā)送一條心跳消息
        this.heartbeatTimer = new Timer();
        this.heartbeatTimer.schedule(new TimerTask() {
            @Override
            public void run() {
                if (!isClosed) {
                    // 發(fā)送心跳消息
                    send("heartbeat");
                }
            }
        }, 30000, 30000);
    }

    private void stopHeartbeat() {
        // 停止心跳定時(shí)器
        if (this.heartbeatTimer != null) {
            this.heartbeatTimer.cancel();
            this.heartbeatTimer = null;
        }
    }

    public static void main(String[] args) throws URISyntaxException {
        // 創(chuàng)建WebSocketClient實(shí)例，并連接到服務(wù)器
        HeartbeatWebSocketClient client = new HeartbeatWebSocketClient(new URI("ws://localhost:8080"));
        client.connect();
    }

}