using java websocket open container shell successfully but no response with following command

[yaoyuanming]

this is the websocket between font end and back end:

File configFile = new File("config/kubeconfig");
final String configYAML;
configYAML = String.join("\n",Files.readAllLines(configFile.toPath()));
Config kubernetesConfig = Config.fromKubeconfig(configYAML);
kubernetesConfig.setTrustCerts(true);

String urlStr = "https://127.0.0.1/api/v1/namespaces/namespace1/pods/pod1/exec?container=container1&stdin=true&stdout=true&stderr=true&tty=true&command=sh&pretty=true&follow=true";
URL url = new URL(urlStr);
clientWebSocketListener = initServerWebSocket(url, kubernetesConfig);
clientWebSocketListener.setSession(session);

@OnMessage
public void onMessage(Session session, byte[] messages) throws UnsupportedEncodingException {
    if (Objects.isNull(session)) {
            return;
        }
        String sessionId = session.getId();
        WebsocketMapping websocketMapping = clients.get(sessionId);
        ClientWebSocketListener listener = websocketMapping.getListener();
        try {
            // 向apiServer发送消息
            listener.waitUntilReady(1);
            listener.send(message.getBytes(), message.length);
        } catch (IOException | InterruptedException ie) {
            // 通知发送方
            session.getAsyncRemote().sendText("向apiServer发送消息失败！失败消息内容： " + message);
        }
}

private static ClientWebSocketListener initServerWebSocket(URL url, Config  config) {
        OkHttpClient client = HttpClientUtils.createHttpClient(config);
        final ClientWebSocketListener serverWebSocketListener = new ClientWebSocketListener();
        final Request.Builder request = new Request.Builder().url(url).get();
        final OkHttpClient clone = client.newBuilder().readTimeout(0, TimeUnit.MILLISECONDS).build();
        clone.newWebSocket(request.build(), serverWebSocketListener);
        return serverWebSocketListener;

    }

here is the onmessage in websocket between apiserver and back end

@Override
    public void onMessage(WebSocket webSocket, ByteString bytes) {
        readyLatch.countDown();
        this.getSession().getAsyncRemote().sendBinary(ByteBuffer.wrap(bytes.toByteArray()));
    }

    @Override
    public void onMessage(WebSocket webSocket, String text) {
        readyLatch.countDown();
        this.getSession().getAsyncRemote().sendText(text);

    }

the problem is this url open container shell successfully but have no response in the following command like ls, or cd bin/. is there are some format conver I miss or some step I miss?

this question confuse me for a long time