java连接homeassistant的websocket并接收消息

可以使用Java中的WebSocket API来连接HomeAssistant的WebSocket，并接收消息。以下是一个简单的示例代码：

import java.net.URI;
import java.net.URISyntaxException;
import java.util.concurrent.CountDownLatch;
import javax.websocket.ClientEndpoint;
import javax.websocket.CloseReason;
import javax.websocket.ContainerProvider;
import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.WebSocketContainer;

@ClientEndpoint
public class HomeAssistantWebSocketClient {

    private CountDownLatch latch;
    private Session session;

    public HomeAssistantWebSocketClient() {
        this.latch = new CountDownLatch(1);
    }

    public void connect(String url) throws URISyntaxException, Exception {
        WebSocketContainer container = ContainerProvider.getWebSocketContainer();
        container.connectToServer(this, new URI(url));
        latch.await();
    }

    @OnOpen
    public void onOpen(Session session) {
        this.session = session;
        latch.countDown();
    }

    @OnMessage
    public void onMessage(String message) {
        System.out.println("Received message: " + message);
    }

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

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

使用该类的示例代码如下：

public static void main(String[] args) throws Exception {
    HomeAssistantWebSocketClient client = new HomeAssistantWebSocketClient();
    client.connect("ws://localhost:8123/api/websocket");
    client.sendMessage("{\"type\": \"ping\"}");
}

其中，`connect`方法用于连接WebSocket，`sendMessage`方法用于发送消息，`onMessage`方法用于接收消息。在实际使用中，需要根据HomeAssistant的API文档来构造正确的消息格式。