IoT Platform:Use IoT Platform SDK for Java

Procedure

1. Initialize the SDK. For more information, see Initialize the SDK.

2. Create an API request by generating a request instance of the ${API name}+"Request" class.

3. Call the set+${Request parameter} method of the request instance to specify the request parameters.

4. Create a response instance of the ${API name}+"Response" class to obtain the response: call the ${API name}(request) method of the client instance to obtain the response to the API request. The response includes the body and headers returned by the server.

5. Use the body object of the response instance and call the get+${Response parameter} method to obtain the values of the response parameters.

   For example, the response.getBody.getSuccess() method is called to obtain the value of the Success parameter. This parameter is a common response parameter, which indicates whether the call is successful. Common response parameters also include RequestId, ErrorMessage, and Code.

6. Call the catch() method to handle exceptions.

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

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

PubRequest request = new PubRequest()
    .setIotInstanceId("${iotInstanceId}")
    .setProductKey("${productKey}")
    .setMessageContent(Base64.getEncoder().encodeToString("hello world".getBytes()))
    .setTopicFullName("/${productKey}/${deviceName}/user/get")
.setQos(0); // QoS0 and QoS1 are supported.  
try {
    PubResponse response = client.pub(request);
// The response that contains the body and the headers that are returned by the server.  
// Obtain the ID of the request. 
    System.out.println(response.getBody().getRequestId());
    // Check whether the call is successful. 
    System.out.println(response.getBody().getSuccess());
    
    // The call is successful. 
    if (response.getBody().getSuccess()) {
        // Obtain the ID of a message that is sent from IoT Platform. 
        System.out.println(response.getBody().getMessageId());
        
        // The else statement. 
        
    } else {
    // The call fails.             
        // Obtain the error code. 
        System.out.println(response.getBody().getCode());
        // Obtain the error description. 
        System.out.println(response.getBody().getErrorMessage());
     }
} catch (TeaException error) {
    // Exceptions that occur on the server. 
    System.out.println(error.getCode());
    System.out.println(error.getMessage());
} catch (Exception e) {
    // Other runtime exceptions. 
    e.printStackTrace();
}

Sample code

import com.aliyun.iot20180120.Client;
import com.aliyun.iot20180120.models.PubRequest;
import com.aliyun.iot20180120.models.PubResponse;
import com.aliyun.tea.TeaException;
import com.aliyun.teaopenapi.models.Config;
import java.util.Base64;

public class IotSdkDemo {
    /**
     * Use your AccessKey ID and AccessKey secret to initialize the client. 
     */
    private static Client createClient(String accessKeyId, String accessKeySecret) throws Exception {
        Config config = new Config();
        config.accessKeyId = accessKeyId;
        config.accessKeySecret = accessKeySecret;
        // The ID of the region. 
        config.regionId = "cn-shanghai";
        return new Client(config);
    }

    public static void main(String[] args) {
        try {
            Client client = createClient(accessKey, accessKeySecret);
            PubRequest request = new PubRequest()
                .setIotInstanceId("${iotInstanceId}")
                .setProductKey("${productKey}")
                .setMessageContent(Base64.getEncoder().encodeToString("hello world".getBytes()))
                .setTopicFullName("/${productKey}/${deviceName}/user/get")
                .setQos(0);// QoS0 and QoS1 are supported.  
            
            PubResponse response = client.pub(request);            
            // Obtain the ID of the request. 
      System.out.println(response.getBody().getRequestId());
      // Check whether the call is successful. 
      System.out.println(response.getBody().getSuccess());
            
         // The call is successful. 
       if (response.getBody().getSuccess()) {
          // Obtain the ID of a message that is sent from IoT Platform. 
          System.out.println(response.getBody().getMessageId());
        
          // The else statement. 
      } else {
       // The call fails.             
          // Obtain the error code. 
             System.out.println(response.getBody().getCode());
          // Obtain the error description. 
          System.out.println(response.getBody().getErrorMessage());
      }
        } catch (TeaException error) {
            // Exceptions that occur on the server. 
      System.out.println(error.getCode());
      System.out.println(error.getMessage());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}