ActiveMQ（九）--持久的Topic消息示例

生产者

import org.apache.activemq.ActiveMQConnectionFactory;

import javax.jms.*;

public class PersistenceSender {
    public static void main(String[] args) throws JMSException, InterruptedException {
        ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("tcp://192.168.25.128:61616");
        Connection connection = connectionFactory.createConnection();
        Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
        Destination destination = session.createTopic("MyTopic2");
        MessageProducer producer = session.createProducer(destination);

        producer.setDeliveryMode(DeliveryMode.PERSISTENT);
        connection.start();

        for (int i = 0; i < 3; i++) {
            TextMessage message = session.createTextMessage("message--" + i);
            producer.send(message);
        }

        session.commit();
        session.close();
        connection.close();
    }
}

消费者

import org.apache.activemq.ActiveMQConnectionFactory;

import javax.jms.*;

public class PersistenceReceiver {
    public static void main(String[] args) throws JMSException {
        //1:需要在连接上设置笑着id，用来识别消费者
        //2.需要创建TopicSubscriber来订阅
        //3.要设置好了过后再start这个connection
        //4.一定要先运行一次，等于向消息服务中间件注册这个消费者，然后在运行客户端发送消息，
        // 这个时候，无论消费者是否在线，都会接收到，不在线的话，下次连接的时候，会把没有收过的消息都接收下来。
        ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("tcp://192.168.25.128:61616");
        Connection connection = connectionFactory.createConnection();
        connection.setClientID("cc1");
        Session session = connection.createSession(true, Session.AUTO_ACKNOWLEDGE);
        Topic destination = session.createTopic("MyTopic2");
        TopicSubscriber ts = session.createDurableSubscriber(destination, "T1");
        connection.start();
        Message message = ts.receive();//receive()是阻塞方法
        while (message != null) {
            TextMessage txtMsg = (TextMessage) message;
            System.out.println("收到消息：" + txtMsg.getText());
            message = ts.receive(1000L);
        }
        session.commit();
        session.close();
        connection.close();
    }
}

先运行消费者，然后停止消费者。看ActiveMQ的状态：

运行生产者：

再运行消费者：

说明，消费者消费消息之后，topic的Messages Dequeued还是0，这是因为，有可能有其他的消费者还订阅了。