spring boot javax.websocket 建立客户端

Spring Boot 中使用 `javax.websocket` 来建立WebSocket客户端通常涉及以下几个步骤：

1. 添加依赖：首先，在Spring Boot项目的pom.xml文件中添加WebSocket相关的依赖，例如官方推荐的`spring-websocket`：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

2. 配置WebSocket支持：在Spring Boot配置类中启用WebSocket并指定一个WebSocketMessageBroker，比如`StompEndpointRegistry`：

@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {
    @Override
    public void configureMessageBroker(MessageBrokerRegistry config) {
        config.enableSimpleBroker("/topic");
        config.setApplicationDestinationPrefixes("/app");
    }

    @Override
    public void registerStompEndpoints(StompEndpointRegistry registry) {
        registry.addEndpoint("/ws").withSockJS();
    }
}

这会创建一个`/ws`端点，并启用对SockJS的支持。

3. 创建WebSocket客户端：在需要连接到服务器的地方，你可以创建一个WebSocketClient实例，然后通过它发送和接收消息：

@Autowired
private WebSocketSession session;

public void connectToServer() {
    StompClient stompClient = new SimpleAsyncClient();
    stompClient.connect(new InMemoryTransport(session), this::handleConnected, this::handleDisconnected);
}

private void handleConnected(WebSocketConnectEvent event) {
    // 连接成功后的处理
    System.out.println("Connected to server");
}

private void handleDisconnected(WebSocketCloseEvent closeEvent) {
    // 断开连接的处理
    System.out.println("Disconnected from server: " + closeEvent.getReasonPhrase());
}

// 发送消息的示例
public void sendMessage(String message) {
    try {
        session.sendMessage(new TextMessage(message));
    } catch (IOException e) {
        // 捕获异常
        e.printStackTrace();
    }
}