IoT Platform:Use IoT Platform SDK for Java

Install the SDK

1. Install a Java development environment.

   Download a Java installation package from the official Java website and install Java as prompted.

2. Install IoT Platform SDK for Java.

   1. Download a Maven installation package from the official Apache Maven website.

   2. Add the following dependencies to your Maven project:

      • Dependency for IoT Platform SDK for Java of the latest version:

        <!-- https://mvnrepository.com/artifact/com.aliyun/aliyun-java-sdk-iot -->
        <dependency>
            <groupId>com.aliyun</groupId>
            <artifactId>aliyun-java-sdk-iot</artifactId>
            <version>7.41.0</version>
        </dependency>

      • Dependency for Alibaba Cloud SDK for Java:

        <dependency>
            <groupId>com.aliyun</groupId>
            <artifactId>aliyun-java-sdk-core</artifactId>
            <version>4.5.6</version>
        </dependency>

Initialize the SDK

Create a profile object of the IClientProfile class to store SDK initialization information. Then, create a client instance of the DefaultAcsClient class. Call the DefaultAcsClient(profile) method to load the SDK initialization information.

String accessKey = System.getenv("ACCESS_KEY_ID");
String accessSecret = System.getenv("ACCESS_KEY_SECRET");
IClientProfile profile = DefaultProfile.getProfile("${RegionId}", accessKey, accessSecret);
DefaultAcsClient client = new DefaultAcsClient(profile); // Initialize an SDK client.

The following example shows how to initialize the SDK if your IoT Platform service resides in the China (Shanghai) region:

String accessKey = System.getenv("ACCESS_KEY_ID");
String accessSecret = System.getenv("ACCESS_KEY_SECRET");
IClientProfile profile = DefaultProfile.getProfile("cn-shanghai", accessKey, accessSecret);
DefaultAcsClient client = new DefaultAcsClient(profile); // Initialize an SDK client.

Initiate a request

The SDK encapsulates two classes for each API operation. The class names are in the ${API operation name}+"Request" and ${API operation name}+"Response" formats.

• ${API operation name}+"Request": This class is used to call an API operation. You can create a request instance of this class and call the set +${request parameter} method to specify the request parameters.

• ${API operation name}+"Response": You can call the getAcsResponse(request) method of the client instance that is created from DefaultAcsClient to obtain a response. You can call the get +${response parameter} method of the response instance of the ${API operation name}+"Response" class to obtain the values of the response parameters.

  For example, you can call the response.getSuccess() method to obtain the Success parameter. This parameter is a common response parameter that indicates whether a request is successful. Common response parameters also include RequestId, ErrorMessage, and Code.

For more information about the API operations of IoT Platform, see List of operations by function. For more information about the request and response parameters of each API operation, see the API documentation.

The following example shows how to call the Pub operation to publish a message to a topic. For more information about the request parameters, see Pub.

PubRequest request = new PubRequest(); 
request.setIotInstanceId("${iotInstanceId}"); 
request.setProductKey("${productKey}"); 
request.setMessageContent(Base64.encodeBase64String("hello world".getBytes())); 
request.setTopicFullName("/${productKey}/${deviceName}/user/get"); 
request.setQos(0); // QoS 0 and QoS 1 are supported.  
try 
{ 
   PubResponse response = client.getAcsResponse(request); 
   System.out.println(response.getSuccess()); 
   System.out.println(response.getCode());
   System.out.println(response.getErrorMessage());
} 
catch (ServerException e) 
{
   e.printStackTrace();
}
catch (ClientException e)
{
   System.out.println("ErrCode:" + e.getErrCode());
   System.out.println("ErrMsg:" + e.getErrMsg());
   e.printStackTrace();
}

Appendix: Sample code

You can view or download the sample code of API operations in IoT Platform SDK Sample Center. The sample code of the SDKs for Java, Python, PHP, .NET, and Go is provided.

Alibaba Cloud OpenAPI Explorer provides online debugging tools for API operations. On the API Debugging page, you can search for API operations, call API operations, and generate sample code for API operations of different SDKs. On the right side of the page, you can view the sample code of an SDK on the Sample Code tab. On the Debugging Result tab, you can view the actual request URL and response in the JSON format.