java调用websocket

Java调用WebSocket可以使用Java API for WebSocket，以下是一个简单的示例代码：

import javax.websocket.*;

@ClientEndpoint
public class WebSocketClient {

    @OnOpen
    public void onOpen(Session session) {
        System.out.println("Connected to server: " + session.getId());
    }

    @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 static void main(String[] args) throws Exception {
        WebSocketContainer container = ContainerProvider.getWebSocketContainer();
        Session session = container.connectToServer(WebSocketClient.class, new URI("ws://localhost:8080/ws"));
        session.getBasicRemote().sendText("Hello, server!");
    }

}

在`@ClientEndpoint`注解中标识了这是一个WebSocket客户端类。`@OnOpen`注解表示连接建立后会触发该方法，`@OnMessage`注解表示接收到消息后会触发该方法，`@OnClose`注解表示连接关闭后会触发该方法。在`main`方法中使用`WebSocketContainer`连接到WebSocket服务器，并可以通过`Session`对象发送消息。