how to use and customize MessageConversion(Spring websocket client)

Question

I wrote a web socket server and a client with spring. The codes is following. The codes sending message to server work, but the sesssion.subscribe method cannot receive message from the server. I search for many documents and check my codes. I don't why it cannot work.

Here is my client codes:

public class Test {

    public static void main(String[] args) {

        Thread thread = new Thread(new WebsocketThread());
        thread.start();
        Thread.sleep(5000);
    }
}

class MyStompSessionHandler extends StompSessionHandlerAdapter {

    @Override
    public void afterConnected(StompSession session, StompHeaders connectedHeaders) {
        session.send("/app/messages", "{'payload3':2222}".getBytes());
        session.subscribe("/user/queue/position-updates", new StompFrameHandler() {

            @Override
            public Type getPayloadType(StompHeaders headers) {
                return String.class;
            }

            @Override
            public void handleFrame(StompHeaders headers, Object payload) {
                System.out.println("test:" + payload);
            }

        });
    }
}

class WebsocketThread implements Runnable{
    @Override
    public void run() {
        List<Transport> transports = new ArrayList<>(1);
        transports.add(new WebSocketTransport( new StandardWebSocketClient()) );
        WebSocketClient webSocketClient = new SockJsClient(transports);
        WebSocketStompClient stompClient = new WebSocketStompClient(webSocketClient);

        String url = "ws://127.0.0.1:8860/orders";
        StompSessionHandler sessionHandler = new MyStompSessionHandler();
        ListenableFuture<StompSession> future = stompClient.connect(url, sessionHandler);
    }
}

Here is my server codes:

@Controller
public class TestController {

    @Autowired
    private SimpMessagingTemplate simpMessagingTemplate;

    @MessageMapping("/messages")
    public void sendUserMsg(String messages) throws IOException {
        System.out.println("webSocket:" + messages);
        simpMessagingTemplate.convertAndSend("/queue/position-updates", "This is return message");
    }
}

It is Exception:

org.springframework.messaging.converter.MessageConversionException: No suitable converter, payloadType=class java.lang.String, handlerType=class com.example.hello.MyStompSessionHandler at org.springframework.messaging.simp.stomp.DefaultStompSession.invokeHandler(DefaultStompSession.java:419) at org.springframework.messaging.simp.stomp.DefaultStompSession.handleMessage(DefaultStompSession.java:373) at org.springframework.web.socket.messaging.WebSocketStompClient$WebSocketTcpConnectionHandlerAdapter.handleMessage(WebSocketStompClient.java:342) at org.springframework.web.socket.sockjs.client.AbstractClientSockJsSession.handleMessageFrame(AbstractClientSockJsSession.java:267) at org.springframework.web.socket.sockjs.client.AbstractClientSockJsSession.handleFrame(AbstractClientSockJsSession.java:200) at org.springframework.web.socket.sockjs.client.WebSocketTransport$ClientSockJsWebSocketHandler.handleTextMessage(WebSocketTransport.java:162) at org.springframework.web.socket.handler.AbstractWebSocketHandler.handleMessage(AbstractWebSocketHandler.java:43) at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.handleTextMessage(StandardWebSocketHandlerAdapter.java:110) at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter.access$000(StandardWebSocketHandlerAdapter.java:42) at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter$3.onMessage(StandardWebSocketHandlerAdapter.java:81) at org.springframework.web.socket.adapter.standard.StandardWebSocketHandlerAdapter$3.onMessage(StandardWebSocketHandlerAdapter.java:78) at org.apache.tomcat.websocket.WsFrameBase.sendMessageText(WsFrameBase.java:399) at org.apache.tomcat.websocket.WsFrameBase.processDataText(WsFrameBase.java:500) at org.apache.tomcat.websocket.WsFrameBase.processData(WsFrameBase.java:295) at org.apache.tomcat.websocket.WsFrameBase.processInputBuffer(WsFrameBase.java:131) at org.apache.tomcat.websocket.WsFrameClient.processSocketRead(WsFrameClient.java:73) at org.apache.tomcat.websocket.WsFrameClient.access$300(WsFrameClient.java:31) at org.apache.tomcat.websocket.WsFrameClient$WsFrameClientCompletionHandler.completed(WsFrameClient.java:131) at org.apache.tomcat.websocket.WsFrameClient$WsFrameClientCompletionHandler.completed(WsFrameClient.java:114) at sun.nio.ch.Invoker.invokeUnchecked(Invoker.java:126) at sun.nio.ch.Invoker$2.run(Invoker.java:218) at sun.nio.ch.AsynchronousChannelGroupImpl$1.run(AsynchronousChannelGroupImpl.java:112) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745)

Answer 1

add a StringMessageConverter to Client, it works.

WebSocketStompClient stompClient = new WebSocketStompClient(webSocketClient);
stompClient.setMessageConverter(new StringMessageConverter());

But how to customize our own MessageConverter? Is there any article?