springboot 实现WebSocket客户端

### 使用 Spring Boot 实现 WebSocket 客户端 为了构建基于 Spring Boot 的 WebSocket 客户端应用程序，可以遵循如下方法： #### 配置 Maven 或 Gradle 依赖项 确保项目的 `pom.xml` 文件中包含了必要的依赖项以支持 WebSocket 功能。对于 Maven 用户来说，应该加入 spring-boot-starter-websocket 依赖。 ```xml <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-websocket</artifactId> </dependency> ``` #### 创建 WebSocketConfig 类配置 WebSocket 连接设置 定义一个名为 `WebSocketConfig.java` 的类用于配置客户端连接参数和其他属性。 ```java import org.springframework.context.annotation.Configuration; import org.springframework.web.socket.client.standard.StandardWebSocketClient; import org.springframework.web.socket.WebSocketSession; import org.springframework.web.socket.sockjs.client.SockJsClient; import org.springframework.web.socket.sockjs.client.Transport; import org.springframework.web.socket.sockjs.client.WebSocketTransport; @Configuration public class WebSocketConfig { private final StandardWebSocketClient standardWebSocketClient = new StandardWebSocketClient(); public SockJsClient sockJsClient() { List<Transport> transports = Collections.singletonList(new WebSocketTransport(standardWebSocketClient)); return new SockJsClient(transports); } } ``` #### 编写 WebSocket Client Handler 处理消息收发逻辑 创建处理来自服务器的消息以及向其发送数据的处理器类 `MyWebSocketHandler.java`. ```java import org.springframework.stereotype.Component; import org.springframework.web.socket.CloseStatus; import org.springframework.web.socket.TextMessage; import org.springframework.web.socket.WebSocketSession; import org.springframework.web.socket.handler.TextWebSocketHandler; @Component public class MyWebSocketHandler extends TextWebSocketHandler { @Override protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception { System.out.println("Received from server: " + message.getPayload()); } @Override public void afterConnectionEstablished(WebSocketSession session) throws Exception { super.afterConnectionEstablished(session); System.out.println("Connected to the WebSocket Server"); } @Override public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception { super.afterConnectionClosed(session, status); System.out.println("Disconnected from the WebSocket Server with reason:" + status.getReason()); } } ``` #### 构建并启动 WebSocket 客户端实例 最后，在主应用程序入口处初始化 WebSocket 客户端，并尝试建立与指定 URL 的连接。 ```java import org.springframework.beans.factory.annotation.Autowired; import org.springframework.messaging.simp.stomp.StompHeaders; import org.springframework.messaging.simp.stomp.StompSession; import org.springframework.messaging.simp.stomp.StompSessionHandlerAdapter; import org.springframework.web.socket.client.standard.StandardWebSocketClient; import org.springframework.web.socket.sockjs.client.SockJsClient; import org.springframework.web.socket.sockjs.client.Transport; import org.springframework.web.socket.sockjs.client.WebSocketTransport; @SpringBootApplication public class Application implements CommandLineRunner { @Autowired private MyWebSocketHandler myWebSocketHandler; public static void main(String[] args) { SpringApplication.run(Application.class, args); } @Override public void run(String... args) throws Exception { String url = "ws://localhost:8080/ws"; // 替换成实际的服务端地址 List<Transport> transports = Collections.singletonList(new WebSocketTransport(new StandardWebSocketClient())); SockJsClient client = new SockJsClient(transports); StompSessionHandlerAdapter handler = new StompSessionHandlerAdapter(myWebSocketHandler){ @Override public Type getPayloadType(StompHeaders headers) { return String.class; } }; CompletableFuture<StompSession> future = client.connect(url, handler); try{ StompSession stompSession = future.get(); while(true){ Thread.sleep(1000); if(!stompSession.isConnected()){ break; } } }catch(Exception e){ e.printStackTrace(); } } } ``` 上述代码展示了如何利用 Spring 提供的标准 API 来快速搭建起一个能够与其他 WebSocket 服务交互的应用程序[^2]。