Question

我们正在进行一项研究，我们使用java Web套接字实时将模拟图像发送到HTML Web客户端。我们注意到系统在研究过程中没有响应，发现如果我们删除了

session.getBasicRemote（）sendBinary（BUF）。

除了没有来自模拟的视频外，

行一切正常。但是，一旦我们添加此行，系统最初会起作用，但最终会变慢/变得无法响应。

我不明白为什么会这样，也不知道该怎么办。任何帮助，将不胜感激。下面我已经包含了一段Java代码，它将图像作为二进制文件抓取并发送给客户端。目前在客户端，我们什么都不做二进制数据接受打印数据的大小。

//Grab a binary version of the image from the simulation.  Occurs 10 fps
protected void schedST_PostStageScreenMessage() {
    LOG.log(Level.FINEST, "schedST_PostStageScreenMessage()");

    //if(getCurrentDisplayMode() == DisplayMode.FULL){
        // get the current proxy state
        ProxyState state = this._robot.getProxy().getCurrentState();
        if (state == null) {
            LOG.log(Level.WARNING, "schedST_PostStageScreenMessage() - no state");
            return;
        }

        // get the latest received screen message from the sim proxy
        ScreenMessage screenMsg = state.msgLastScreen();
        if(screenMsg == null) {
            LOG.log(Level.FINER, "schedST_PostStageScreenMessage() - no update");
            return;
        }

        // check to see if it has been updated since last time
        if(this._screenMsg == screenMsg) {
            LOG.log(Level.FINEST, "schedST_PostStageScreenMessage() - no screen message update");
            return;
        }

        this._screenMsg = screenMsg;
        ScreenResponse sr = (ScreenResponse)createSceneMessage();
        doPost(sr.getPngData());
        //doPost(createSceneMessage());
    //}

}

private void doPost(byte[] message){
    try {
        postMessage(message);

    } catch (Exception e) {
        LOG.log(Level.SEVERE, "Caught: " + e, e);
    }
}

 protected void postMessage(byte[] message) {
                WebSocketEndpointERA.sendToAll(message);
            }

public static void sendToAll(final byte[] data){
    ByteBuffer buf = ByteBuffer.wrap(data);
    System.out.println("Sending bytes of length: " + data.length);
    Set<Session> sessions = getSessions();
    try{
        for (Session session : sessions) {
            //When this line is commented out the system works
            //However when we send the binary image the system works initially
            //and then becomes unresponsive
            session.getBasicRemote().sendBinary(buf);


        }
    }catch(IOException io){
         LOG.log(Level.SEVERE, "unable to send binary message: {0}", io);
    }
    buf = null;
}

在Javascript方面，我们暂时使用以下内容进行测试

function onMessage(event) {
    //console.log('Received a message!');
    if (event.data instanceof ArrayBuffer) {
        //handleBinaryEventMessage(event.data);
        //Do nothing with the binary data right now
        return;
    }

    var msg = JSON.parse(event.data);
    //writeToMessages("Received message: " + msg.type);
    switch (msg.type) {
        case 'RobotPoseResponse':
            handleRobotPoseMessage(msg);
            break;
        case 'RobotAcousticResponse':
            handleRobotSensorDataMessage(msg);
            break;
        case 'RobotGoalResponse':
            handleRobotGoalMessage(msg);
            break;
        case 'AvailableQuestionsResponse':
            handleOptionsEventMessage(msg);
            break;
        case 'ExplanationResponse':
            handleExplanationMessage(msg);
            break;
        case 'ScenarioResponse':
            handleScenarioMessage(msg);
            break;
        case 'ScreenResponse':
            handleScreenMessage(msg);
            break;
        case 'SceneResponse':
            handleSceneMessage(msg);
            break;
        case 'StageStartUpResponse':
            handleStageStartUp(msg);
            break;
        default:
            writeToEvents("Received unhandled message: " + msg.type);
    }
}

Answer 1

所以我相信我已经回答了我自己的问题。我们将Websockets从同步切换到异步，这似乎解决了我们Mac上的问题。出于某种原因，在Ubunutu上进行测试时异步不起作用。我不清楚为什么从同步切换到异步会解决这种情况。

在代码中我们切换了以下内容

来自

session.getBasicRemote().sendBinary(buf);

到

session.getAsyncRemote().sendBinary(buf);

谢谢

使用java websockets实时流式传输模拟视频会随着时间的推移而变得无法响应

1 个答案: