如何使用 android 从 Azure IoT 中心读取设备到云？

Question

我有一块板可以将 jsons 和遥测数据发送到 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 android 的 IoT 中心读取消息的示例，但我只发现了如何从 "Cloud to device feedback" 端点读取它们。所以现在我的应用程序看起来像：

Json from the board ----> "Events" endpoint ---> Function application that resending json to "Cloud to device feedback" endpoint -----> "Cloud to device feedback" 端点 ----> Android 设备。

我是 Azure 的初学者，所以我确信存在更聪明的方法来做到这一点。 （Json 来自开发板 ----> "Events" 端点 ---> Android 设备）。我是在桌面上完成的，但看起来 android 不适用于桌面项目中的某些库。

有人知道我该怎么做吗？（也许是一些指南或课程）

Desktop version

部分android代码：

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。它展示了如何使用 Java.In 和 ReadDeviceToCloudMessages.java 示例从您的 IoT 中心读取遥测数据，它连接到服务端事件端点在您的 IoT 中心上并接收设备到云的消息。

顺便说一句，您可以简单地从 Azure 门户获取 eventHubsCompatibleEndpoint、eventHubsCompatiblePath 和 iotHubSasKey。 eventHubsCompatibleEndpoint 格式如下：

sb://xxxxxxxxxxxxxx.servicebus.windows.net/

如何使用 android 从 Azure IoT 中心读取设备到云？

How to read device-to-cloud from Azure IoT hub with android?

java

android

azure

iot

azure-iot-hub