有没有办法在 java 应用程序中创建 websocket 客户端以与 node.js websocket 服务器通信？

Question

目前，我正在开发一个在 tomcat 服务器上运行的 java spring 应用程序，我想在那里创建一个 WebSocket 客户端来与本地运行的 node.js websocket 服务器通信。我找不到客户的任何实现。客户端必须在视图（.jsp 文件）中还是在控制器中？ websocket 客户端必须在 web 应用程序中。

这里是node.js服务器的实现：

const WebSocket = require('ws');
const express = require('express')
const app = express()
const server = require('http').createServer(app);

const wss = new WebSocket.Server({ server:server });

wss.on('connection', function connection(ws) {
    console.log('A new client Connected!');

    ws.binaryType = 'arraybuffer';
    ws.on('message', function incoming(message) {
    
        const array = new Int16Array(message);
        
        //console.log(array);
        console.log(new Date().toLocaleString().replace(',',' ')+" " + ' Data received');
        ws.send('The server received the message!'); 
    });
});
server.listen(3000, () => console.log(`Lisening on port :3000`))

Answer 1

如果你使用js，你应该使用WebSocket js obj来实现它。网上还有更多样片。我猜你想用java构建一个websocket客户端。所以你可以参考this 来构建客户端。下面是简单的演示。

maven 依赖

        <dependency>
            <groupId>org.java-websocket</groupId>
            <artifactId>Java-WebSocket</artifactId>
            <version>1.5.1</version>
        </dependency>

websocket 客户端

public class MyWebSocketClient extends WebSocketClient {
    private static final Logger LOGGER = LoggerFactory.getLogger(MyWebSocketClient.class);

    public MyWebSocketClient(URI serverUri) {
        super(serverUri);
    }

    @Override
    public void onOpen(ServerHandshake arg0) {
        // TODO Auto-generated method stub
        LOGGER.info("------ MyWebSocket onOpen ------");
    }

    @Override
    public void onClose(int arg0, String arg1, boolean arg2) {
        // TODO Auto-generated method stub
        LOGGER.info("------ MyWebSocket onClose ------{}",arg1);
    }

    @Override
    public void onError(Exception arg0) {
        // TODO Auto-generated method stub
        LOGGER.info("------ MyWebSocket onError ------{}",arg0);
    }

    @Override
    public void onMessage(String arg0) {
        // TODO Auto-generated method stub
        LOGGER.info("-------- receive data from websocket server： " + arg0 + "--------");
    }
}

定义一个要使用的bean

@SpringBootApplication
public class WebSocketApplication {
    public static void main(String[] args){
        SpringApplication.run(WebSocketApplication.class, args);
    }

        @Bean
    public WebSocketClient webSocketClient() {
        try {
            MyWebSocketClient webSocketClient = new MyWebSocketClient(new URI("ws://127.0.0.1:3000/connection"));
            webSocketClient.connect();
            return webSocketClient;
        } catch (URISyntaxException e) {
            e.printStackTrace();
        }
        return null;
    }
   
}

在一个restController中调用

@RestController
public class WebSocketController {

    @Autowired
    private WebSocketClient webSocketClient;

    @RequestMapping("subscribe")
    public String subscribe() {
        webSocketClient.send("hello sever，i want subscribe data A");
        return "send ok";
    }
}