Question

我有一个电路板，可以将具有遥测功能的jsons发送到Azure IoT中心（使用http）。我想用我的Android设备读取遥测数据。我查看了一些从IoT hub for android读取消息的示例，但我发现只能从“云到设备反馈”端点读取它们。所以现在我的应用程序看起来像：

董事会的Json ----＆gt; “事件”端点---＆gt;将json重新发送到“云到设备反馈”端点的功能应用程序 -----＆GT; “云到设备反馈”端点----＆gt; Android设备。

我是Azure的初学者，所以我确信存在更聪明的方法。 （董事会的Json ----＆gt;“事件”端点---＆gt; Android设备）。我在我的桌面上做到了，但看起来像android不能与桌面项目中的某些库一起使用。

有谁知道我该怎么办？（也许是一些指南或课程）

Desktop version

Android代码的一部分：

public void btnReceiveOnClick(View v) throws URISyntaxException, IOException
{
    System.out.println("Receiving:");
    Button button = (Button) v;

    // Comment/uncomment from lines below to use HTTPS or MQTT protocol
    //IotHubClientProtocol protocol = IotHubClientProtocol.HTTPS;
    IotHubClientProtocol protocol = IotHubClientProtocol.MQTT;

    DeviceClient client = new DeviceClient(connString, protocol);

    if (protocol == IotHubClientProtocol.MQTT)
    {
        MessageCallbackMqtt callback = new MessageCallbackMqtt();
        Counter counter = new Counter(0);
        client.setMessageCallback(callback, counter);
    } else
    {
        MessageCallback callback = new MessageCallback();
        Counter counter = new Counter(0);
        client.setMessageCallback(callback, counter);
    }

    try
    {
        client.open();
    } catch (Exception e2)
    {
        System.out.println("Exception while opening IoTHub connection: " + e2.toString());
    }

    try
    {
        Thread.sleep(1000);
    } catch (InterruptedException e)
    {
        e.printStackTrace();
    }

    client.closeNow();

    try {
        ....

    }catch (JSONException je){
        ....
    }
}



// Our MQTT doesn't support abandon/reject, so we will only display the messaged received
// from IoTHub and return COMPLETE
static class MessageCallbackMqtt implements com.microsoft.azure.sdk.iot.device.MessageCallback
{
    public IotHubMessageResult execute(Message msg, Object context)
    {
        responce = new String(msg.getBytes(), Message.DEFAULT_IOTHUB_MESSAGE_CHARSET);
        Counter counter = (Counter) context;
        System.out.println(
                "[from MessageCallbackMqtt] Received message " + counter.toString()
                        + " with content: " + responce);

        counter.increment();
        return IotHubMessageResult.COMPLETE;
    }
}

static class EventCallback implements IotHubEventCallback
{
    public void execute(IotHubStatusCode status, Object context)
    {
        Integer i = (Integer) context;
        System.out.println("[from EventCallback]  IoT Hub responded to message " + i.toString()
                + " with status " + status.name());
    }
}

static class MessageCallback implements com.microsoft.azure.sdk.iot.device.MessageCallback
{
    public IotHubMessageResult execute(Message msg, Object context)
    {
        Counter counter = (Counter) context;
        System.out.println(
                "Received message " + counter.toString()
                        + " with content: " + new String(msg.getBytes(), Message.DEFAULT_IOTHUB_MESSAGE_CHARSET));

        int switchVal = counter.get() % 3;
        IotHubMessageResult res;
        switch (switchVal)
        {
            case 0:
                res = IotHubMessageResult.COMPLETE;
                break;
            case 1:
                res = IotHubMessageResult.ABANDON;
                break;
            case 2:
                res = IotHubMessageResult.REJECT;
                break;
            default:
                // should never happen.
                throw new IllegalStateException("Invalid message result specified.");
        }

        System.out.println("Responding to message " + counter.toString() + " with " + res.name());
        counter.increment();
        return res;
    }
}

Answer 1

您可以参考此document。它显示了如何使用Java从IoT Hub读取遥测。在ReadDeviceToCloudMessages.java示例中，它连接到IoT Hub上的服务端Events端点并接收设备到云的消息。

顺便说一下，您可以从Azure门户获取 eventHubsCompatibleEndpoint ，eventHubsCompatiblePath和 iotHubSasKey 。 eventHubsCompatibleEndpoint 采用以下格式：

SB：//xxxxxxxxxxxxxx.servicebus.windows.net/

如何使用android从Azure IoT中心读取设备到云？

1 个答案: