消费者从 Apache ActiveMQ Artemis 中的接收方法接收单个消息

Question

我正在我的项目中实现 Apache ActiveMQ Artemis，它连接到 Artemis 远程服务器。所以我首先决定创建一个包含生产者和消费者的独立项目。

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.MessageConsumer;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.naming.Context;
import javax.naming.InitialContext;

import org.apache.activemq.artemis.api.jms.ActiveMQJMSClient;
import org.apache.activemq.artemis.utils.UUIDGenerator;

/**
 * A simple JMS Queue example that creates a producer and consumer on a queue and sends then receives a message.
 */
public class QueueExample {

   public static void main(final String[] args) throws Exception {
      Connection connection = null;

   try {

         ConnectionFactory cf = ActiveMQJMSClient.createConnectionFactory("tcp://54.67.23.67:61616",  UUIDGenerator.getInstance().generateStringUUID());
         // Step 4.Create a JMS Connection
         connection = cf.createConnection("test","test123");

         // Step 5. Create a JMS Session
         Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);

         // Step 6. Create a JMS Message Producer
         MessageProducer producer = session.createProducer(null);

         // Step 7. Create a Text Message
         TextMessage message1 = session.createTextMessage("This is a text message1");
         Thread.sleep(1000l);
         TextMessage message2 = session.createTextMessage("This is a text message2");


         System.out.println("Sent message: " + message1.getText());

         System.out.println("Sent message: " + message2.getText());

         Destination destination = session.createQueue("TESTQUEUE");

         // Step 8. Send the Message
         producer.send(destination,message1);
         producer.send(destination,message2);

         // Step 9. Create a JMS Message Consumer
         MessageConsumer messageConsumer = session.createConsumer(destination);

         // Step 10. Start the Connection
         connection.start();

         // Step 11. Receive the message
         TextMessage messageReceived = (TextMessage) messageConsumer.receive(5000);

         System.out.println("Received message: " + messageReceived.getText());
      } finally {
         // Step 12. Be sure to close our JMS resources!
         if (initialContext != null) {
            initialContext.close();
         }
         if (connection != null) {
            connection.close();
         }
      }
   }
}

我从生产者发送消息 2 次，但在消费时我只收到 1 条消息。以下是我收到的输出：

收到

Sent message: This is a text message1
Sent message: This is a text message2
Received message: This is a text message1 

预期

Sent message: This is a text message1
Sent message: This is a text message2
Received message: This is a text message1
Received message: This is a text message2

当我再次运行代码时，我得到了Received message: This is a text message2，但我同时想要消息 Message1 和 Message2。

这里发生了什么？谁能指导我，因为我尝试搜索这个问题但没有找到结果。

我的 Artemis 服务器配置不正确，还是代码有问题？

Answer 1

您正在看到预期的行为。调用 receive 最多会返回 1 条消息。如果您想收到更多消息，您需要多次致电receive - 每条您想收到的消息一次，例如：

TextMessage messageReceived = (TextMessage) messageConsumer.receive(5000);

System.out.println("Received message: " + messageReceived.getText());

messageReceived = (TextMessage) messageConsumer.receive(5000);

System.out.println("Received message: " + messageReceived.getText());

更多信息请查看the JavaDoc for javax.jms.MessageConsumer.receive(long)