ApsaraMQ for RocketMQ:Send and consume scheduled or delayed messages

import com.aliyun.mq.http.MQClient;
import com.aliyun.mq.http.MQProducer;
import com.aliyun.mq.http.model.TopicMessage;

import java.util.Date;

public class Producer {

    public static void main(String[] args) {
        MQClient mqClient = new MQClient(
                // HTTP endpoint. Find this on the Instance Details page, in the
                // Endpoints tab under Basic Information.
                "<your-http-endpoint>",
                // Load credentials from environment variables to avoid hardcoding secrets.
                System.getenv("ALIBABA_CLOUD_ACCESS_KEY_ID"),
                System.getenv("ALIBABA_CLOUD_ACCESS_KEY_SECRET")
        );

        final String topic = "<your-topic>";
        // If the instance has a namespace, specify the instance ID.
        // If it does not have a namespace, set this to null or "".
        final String instanceId = "<your-instance-id>";

        MQProducer producer;
        if (instanceId != null && instanceId != "") {
            producer = mqClient.getProducer(instanceId, topic);
        } else {
            producer = mqClient.getProducer(topic);
        }

        try {
            for (int i = 0; i < 4; i++) {
                TopicMessage pubMsg = new TopicMessage(
                        "hello mq!".getBytes(),   // Message body
                        "A"                        // Message tag
                );
                pubMsg.getProperties().put("a", String.valueOf(i));  // Custom property
                pubMsg.setMessageKey("MessageKey");

                // Defer delivery by 10 seconds.
                // For a scheduled message, use an absolute timestamp instead,
                // e.g., pubMsg.setStartDeliverTime(1654770600000L);
                pubMsg.setStartDeliverTime(System.currentTimeMillis() + 10 * 1000);

                TopicMessage pubResultMsg = producer.publishMessage(pubMsg);

                System.out.println(new Date() + " Send mq message success."
                        + " Topic is:" + topic
                        + ", msgId is: " + pubResultMsg.getMessageId()
                        + ", bodyMD5 is: " + pubResultMsg.getMessageBodyMD5());
            }
        } catch (Throwable e) {
            System.out.println(new Date() + " Send mq message failed. Topic is:" + topic);
            e.printStackTrace();
        }

        mqClient.close();
    }
}

import com.aliyun.mq.http.MQClient;
import com.aliyun.mq.http.MQConsumer;
import com.aliyun.mq.http.common.AckMessageException;
import com.aliyun.mq.http.model.Message;

import java.util.ArrayList;
import java.util.List;

public class Consumer {

    public static void main(String[] args) {
        MQClient mqClient = new MQClient(
                // HTTP endpoint. Find this on the Instance Details page, in the
                // Endpoints tab under Basic Information.
                "<your-http-endpoint>",
                // The AccessKey ID for authentication.
                "${ACCESS_KEY}",
                // The AccessKey secret for authentication.
                "${SECRET_KEY}"
        );

        final String topic = "<your-topic>";
        final String groupId = "<your-group-id>";
        // If the instance has a namespace, specify the instance ID.
        // If it does not have a namespace, set this to null or "".
        final String instanceId = "<your-instance-id>";

        final MQConsumer consumer;
        if (instanceId != null && instanceId != "") {
            consumer = mqClient.getConsumer(instanceId, topic, groupId, null);
        } else {
            consumer = mqClient.getConsumer(topic, groupId);
        }

        // Consume messages in a loop. For production use, run multiple threads
        // to consume messages concurrently.
        do {
            List<Message> messages = null;

            try {
                // Long polling: wait up to 3 seconds for new messages.
                // - First parameter: max messages per batch (max: 16).
                // - Second parameter: long polling timeout in seconds (max: 30).
                messages = consumer.consumeMessage(3, 3);
            } catch (Throwable e) {
                e.printStackTrace();
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e1) {
                    e1.printStackTrace();
                }
            }

            if (messages == null || messages.isEmpty()) {
                System.out.println(Thread.currentThread().getName()
                        + ": no new message, continue!");
                continue;
            }

            // Process messages
            for (Message message : messages) {
                System.out.println("Receive message: " + message);
            }

            // ACK consumed messages. If the broker does not receive an ACK
            // before the retry interval elapses, the message is redelivered.
            {
                List<String> handles = new ArrayList<String>();
                for (Message message : messages) {
                    handles.add(message.getReceiptHandle());
                }

                try {
                    consumer.ackMessage(handles);
                } catch (Throwable e) {
                    if (e instanceof AckMessageException) {
                        AckMessageException errors = (AckMessageException) e;
                        System.out.println("Ack message fail, requestId is:"
                                + errors.getRequestId() + ", fail handles:");
                        if (errors.getErrorMessages() != null) {
                            for (String errorHandle : errors.getErrorMessages().keySet()) {
                                System.out.println("Handle:" + errorHandle
                                        + ", ErrorCode:" + errors.getErrorMessages().get(errorHandle).getErrorCode()
                                        + ", ErrorMsg:" + errors.getErrorMessages().get(errorHandle).getErrorMessage());
                            }
                        }
                        continue;
                    }
                    e.printStackTrace();
                }
            }
        } while (true);
    }
}