ApsaraMQ for RocketMQ:Step 3: Use SDKs to send and receive messages

Install the Java dependency library

1. Create a Java project in IntelliJ IDEA.

2. Add the following dependency to the pom.xml file to import the Java dependency library:

   <dependency>
       <groupId>org.apache.rocketmq</groupId>
       <artifactId>rocketmq-client-java</artifactId>
       <version>5.0.7</version>
   </dependency>

   Important

   If you use a serverless ApsaraMQ for RocketMQ instance, take note of the version of the SDK for Java when you access the instance over the Internet. Only the SDK for Java of specific versions can access serverless ApsaraMQ for RocketMQ instances over the Internet. For more information, see Version description for accessing serverless instances over the Internet

Produce messages

In the created Java project, create a program that sends normal messages and run the program. Sample code:

package doc;

import org.apache.rocketmq.client.apis.*;
import org.apache.rocketmq.client.apis.message.Message;
import org.apache.rocketmq.client.apis.producer.Producer;
import org.apache.rocketmq.client.apis.producer.SendReceipt;


public class ProducerExample {
    public static void main(String[] args) throws ClientException {
        /**
         * The endpoint of the instance. You can view the endpoint on the Endpoints tab of the Instance Details page in the ApsaraMQ for RocketMQ console. 
         * If the client of the ApsaraMQ for RocketMQ instance is deployed on an Elastic Compute Service (ECS) instance and you want to access the ApsaraMQ for RocketMQ instance in an internal network, we recommend that you specify the virtual private cloud (VPC) endpoint. 
         * If you access the instance over the Internet or from a data center, you can specify the public endpoint. If you access the instance over the Internet, you must enable the Internet access feature for the instance. 
         */
        String endpoints = "rmq-cn-xxx.{regionId}.rmq.aliyuncs.com:8080";
        // The name of the topic to which the message is sent. Before you use a topic to receive a message, you must create the topic in the ApsaraMQ for RocketMQ console. Otherwise, an error is returned. 
        String topic = "Your Topic";
        ClientServiceProvider provider = ClientServiceProvider.loadService();
        ClientConfigurationBuilder builder = ClientConfiguration.newBuilder().setEndpoints(endpoints);
        /**
         * If you access the instance by using the public endpoint, you must specify the username and password of the instance. You can obtain the username and password on the Intelligent Authentication tab of the Access Control page corresponding to the instance in the ApsaraMQ for RocketMQ console. 
         * If the client of the ApsaraMQ for RocketMQ instance is deployed on an ECS instance and you want to access the ApsaraMQ for RocketMQ instance in an internal network, you do not need to specify the username or password. The broker automatically obtains the username and password based on the VPC information. 
         * If the instance is a serverless ApsaraMQ for RocketMQ instance, you must specify the username and password to access the instance over the Internet. If you enable the authentication-free in VPCs feature for the serverless instance and access the instance in a VPC, you do not need to specify the username or password. 
         */
        //builder.setCredentialProvider(new StaticSessionCredentialsProvider("Instance UserName", "Instance Password"));
        ClientConfiguration configuration = builder.build();
        /**
         * When you initialize a producer, you can specify the topics that you want to use to check whether the topic settings are valid and prevent invalid topics from being started. 
         * You do not need to specify the topics for non-transactional messages. The broker dynamically checks whether the topics are valid. 
         * Note: To prevent the API operation that is called to query transactional messages from failing, you must specify topics for transactional messages in advance. 
         */
        Producer producer = provider.newProducerBuilder()
                .setTopics(topic)
                .setClientConfiguration(configuration)
                .build();
        // Send a normal message. 
        Message message = provider.newMessageBuilder()
                .setTopic(topic)
                // The message key. You can use a keyword to accurately find the message. 
                .setKeys("messageKey")
                // The message tag. The consumer can use the tag to filter messages. 
                .setTag("messageTag")
                // The message body. 
                .setBody("messageBody".getBytes())
                .build();
        try {
            // Send the message. Take note of the result and capture exceptions such as failures. 
            SendReceipt sendReceipt = producer.send(message);
            System.out.println(sendReceipt.getMessageId());
        } catch (ClientException e) {
            e.printStackTrace();
        }
    }
}

Consume messages

Version description for accessing serverless instances over the Internet

Only SDKs of specific versions can access serverless ApsaraMQ for RocketMQ instances over the Internet.

SDK parameters

Verify message consumption

After you consume a message, you can check the consumption status of the message in the ApsaraMQ for RocketMQ console.

1. Log on to the ApsaraMQ for RocketMQ console. On the Instances page, click the name of the instance that you want to manage.

2. In the left-side navigation pane of the page that appears, click Message Tracing.

SDK references

For information about how to use SDKs for other programming languages to send and receive messages of other types, see Overview.