设备接收云端指令

设备成功上报消息后，您可以尝试从云端下发指令到设备端。本文档讲解了如何通过云端应用调用SetDeviceProperty接口，设置产品属性。同时，设备成功接收云端指令。

1. 在Maven项目中加入依赖项。

   IoT Java SDK的Maven依赖坐标

   <!-- https://mvnrepository.com/artifact/com.aliyun/aliyun-java-sdk-iot -->
   <dependency>
       <groupId>com.aliyun</groupId>
       <artifactId>aliyun-java-sdk-iot</artifactId>
       <version>6.8.0</version>
   </dependency>

   依赖公共包

   <dependency>
       <groupId>com.aliyun</groupId>
       <artifactId>aliyun-java-sdk-core</artifactId>
       <version>3.5.1</version>
   </dependency>

2. 初始化SDK。

   此处地域与产品地域保持一致，使用华东2。

   String accessKey = "<your accessKey>";
   String accessSecret = "<your accessSecret>";
   DefaultProfile.addEndpoint("cn-shanghai", "cn-shanghai", "Iot", "iot.cn-shanghai.aliyuncs.com");
   IClientProfile profile = DefaultProfile.getProfile("cn-shanghai", accessKey, accessSecret);
   DefaultAcsClient client = new DefaultAcsClient(profile); 

3. 云端应用向设备下发属性设置指令，将开关属性设置为1。

   示例如下：

   SetDevicePropertyRequest request = new SetDevicePropertyRequest();
   request.setProductKey("a1zluR09W76");
   request.setDeviceName("device1");
   JSONObject itemJson = new JSONObject();
   itemJson.put("PowerSwitch", 1);
   request.setItems(itemJson.toString());
   
   try {
       SetDevicePropertyResponse response = client.getAcsResponse(request);
       System.out.println(response.getRequestId() + ", success: " + response.getSuccess());
   } catch (ClientException e) {
       e.printStackTrace();
   }

   说明 属性设置的具体调用方法，请参见SetDeviceProperty。

< {
<     "method": "thing.service.property.set",
<     "id": "432801169",
<     "params": {
<         "PowerSwitch": 1
<     },
<     "version": "1.0.0"
< }

user_report_reply_event_handler.94: Message Post Reply Received, Message ID: 646, Code: 200, Reply: {}
user_property_set_event_handler.114: Property Set Received, Request: {"PowerSwitch":1}

> {
>     "id": "647",
>     "version": "1.0",
>     "params": {
>         "PowerSwitch": 1
>     },
>     "method": "thing.event.property.post"
> }