Question

使用Ning创建并连接到Websocket，以下是我的配置

 NettyAsyncHttpProviderConfig config = new NettyAsyncHttpProviderConfig();
 config.addProperty(NettyAsyncHttpProviderConfig.USE_BLOCKING_IO, "true");

 AsyncHttpClientConfig.Builder builder = new AsyncHttpClientConfig.Builder()
                .setAsyncHttpClientProviderConfig(config);

 AsyncHttpClient client = new AsyncHttpClient(
                new NettyAsyncHttpProvider(builder.build()));

 AsyncHttpClient.BoundRequestBuilder requestBuilder = client.prepareGet(createUri(method))
                .addHeader(HttpHeaders.Names.CONNECTION, "Upgrade")
                .addHeader(HttpHeaders.Names.UPGRADE, "WebSocket");

 websocket = requestBuilder.execute(new WebSocketUpgradeHandler.Builder()
                .addWebSocketListener(this).build()).get();

使用websocket发送短信，

 if (websocket!=null && websocket.isOpen())
       websocket.sendTextMessage(jObj.toString());// send

监听器的

onMessage()方法将响应添加到列表

@Override
public void onMessage(String message) {
   serverResponse.add(message);
}

发送短信后，我有方法格式化响应并保存结果

result = responseFromServer();

private String responseFromServer() {
    String response = null;
    sleep(100);
   if(!serverResponse.isEmpty())
      //format the message which is added in list
    return response;
}

问题是，如果我在上面的方法中没有'sleep（100）'，对于request1- response为null，对于request2，我得到response1。我希望websocket能够同步工作，这样，一旦我发送消息，就应该等待响应接收并继续前进！任何建议！

Answer 1

在对象上使用wait和notify

synchronized (someObject){
  try {
     someObject.wait();
     result = responseFromServer();
   } catch (InterruptedException e) {
        //when the object is interrupted
   }
}

并在onMessage收到消息后通知对象

@Override
public void onMessage(String message) {
     serverResponse.add(message);
     synchronized(someObject) {
          someObject.notify();
     }
}

Answer 2

您还可以使用CountDownLatch概念，如下面的链接所示：



@ClientEndpoint
public class WordgameClientEndpoint {

    private static CountDownLatch latch;

    private Logger logger = Logger.getLogger(this.getClass().getName());

    @OnOpen
    public void onOpen(Session session) {
        // same as above
    }

    @OnMessage
    public String onMessage(String message, Session session) {
        // same as above
    }

    @OnClose
    public void onClose(Session session, CloseReason closeReason) {
        logger.info(String.format("Session %s close because of %s", session.getId(), closeReason));
        latch.countDown();
    }

    public static void main(String[] args) {
        latch = new CountDownLatch(1);

        ClientManager client = ClientManager.createClient();
        try {
            client.connectToServer(WordgameClientEndpoint.class, new URI("ws://localhost:8025/websockets/game"));
            latch.await();

        } catch (DeploymentException | URISyntaxException | InterruptedException e) {
            throw new RuntimeException(e);
        }
    }
}

@ClientEndpoint public class WordgameClientEndpoint { private static CountDownLatch latch; private Logger logger = Logger.getLogger(this.getClass().getName()); @OnOpen public void onOpen(Session session) { // same as above } @OnMessage public String onMessage(String message, Session session) { // same as above } @OnClose public void onClose(Session session, CloseReason closeReason) { logger.info(String.format("Session %s close because of %s", session.getId(), closeReason)); latch.countDown(); } public static void main(String[] args) { latch = new CountDownLatch(1); ClientManager client = ClientManager.createClient(); try { client.connectToServer(WordgameClientEndpoint.class, new URI("ws://localhost:8025/websockets/game")); latch.await(); } catch (DeploymentException | URISyntaxException | InterruptedException e) { throw new RuntimeException(e); } } }

https://blog.openshift.com/how-to-build-java-websocket-applications-using-the-jsr-356-api/

Ning：连接到websocket并等待响应

2 个答案: