基本的Queue消息发送和消费

配置Maven所需的依赖，示例如下

<dependency>
    <groupId>org.apache.activemq</groupId>
    <artifactId>activemq-all</artifactId>
    <version>5.2.0</version>
</dependency>

<dependency>
    <groupId>org.apache.xbean</groupId>
    <artifactId>xbean-spring</artifactId>
    <version>3.7</version>
</dependency>

Queue消息发送的示例代码如下：

public class JmsProducer {

    public static void main(String[] args) {
        try {
            ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("tcp://39.96.192.171:61616");
            Connection connection = connectionFactory.createConnection();
            connection.start();
            Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
            Destination destination = session.createQueue("my-queue");
            MessageProducer producer = session.createProducer(destination);
            for (int i = 0; i < 3; i++) {
                TextMessage message = session.createTextMessage("message--" + i);

                Thread.sleep(1000);
                //通过消息生产者发出消息
                producer.send(message);
            }
            session.commit();
            session.close();
            connection.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

然后运行这个类

可以看到队列中我们自定义的my-queue，中有3个还没有被消费的消息！

接下来我们编写消费者来消费消息！

public class JmsReceiver {
    public static void main(String[] args) {
        try {
            ConnectionFactory cf = new ActiveMQConnectionFactory("tcp://39.96.192.171:61616");
            Connection connection = cf.createConnection();
            connection.start();
            final Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
            Destination destination = session.createQueue("my-queue");
            MessageConsumer consumer = session.createConsumer(destination);
            int i = 0;
            while (i < 3) {
                i++;
                TextMessage message = (TextMessage) consumer.receive();
                session.commit();
                System.out.println("收到消息：" + message.getText());
            }
            session.close();
            connection.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

运行这个类！可以看到控制台收到3条消息！

再看activemq控制台

可以看到有3条消息显示被消费！

这就是简单的消息生产和消费！消息消费分为两种方式，同步消费和异步消费，上面的例子就是同步消费，通过调用消费者的receive方法从目的地中显式提取消息，receive 方法可以一直阻塞到消息到达。

然后再写一个异步消费的例子！

public class JmsReceiver2 implements MessageListener {

    public void onMessage(Message message) {
        try {
            TextMessage textMessage = (TextMessage) message;
            if (null != message) {
                System.out.println("收到的消息：" + textMessage.getText());
            }
            // 如果session设置为Session.CLIENT_ACKNOWLEDGE,要加上这一步
            message.acknowledge();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    }