Queue实现的是点到点模型,在下面的例子中,启动2个消费者共同监听一个Queue,然后循环给这个Queue中发送多个消息,我们依然采用ActiveMQ。
package com.bijian.study; import javax.jms.Connection; import javax.jms.JMSException; import javax.jms.Message; import javax.jms.MessageConsumer; import javax.jms.MessageListener; import javax.jms.MessageProducer; import javax.jms.Queue; import javax.jms.Session; import javax.jms.TextMessage; import org.apache.activemq.ActiveMQConnectionFactory; import org.apache.activemq.command.ActiveMQQueue; public class QueueTest { public static void main(String[] args) throws Exception { ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory("tcp://localhost:61616"); Connection connection = factory.createConnection(); connection.start(); // 创建一个Queue Queue queue = new ActiveMQQueue("testQueue"); // 创建一个Session Session session = connection.createSession(false,Session.AUTO_ACKNOWLEDGE); // 注册消费者1 MessageConsumer comsumer1 = session.createConsumer(queue); comsumer1.setMessageListener(new MessageListener() { public void onMessage(Message m) { try { System.out.println("Consumer1 get " + ((TextMessage) m).getText()); } catch (JMSException e) { e.printStackTrace(); } } }); // 注册消费者2 MessageConsumer comsumer2 = session.createConsumer(queue); comsumer2.setMessageListener(new MessageListener() { public void onMessage(Message m) { try { System.out.println("Consumer2 get " + ((TextMessage) m).getText()); } catch (JMSException e) { e.printStackTrace(); } } }); // 创建一个生产者,然后发送多个消息。 MessageProducer producer = session.createProducer(queue); for (int i = 0; i < 10; i++) { producer.send(session.createTextMessage("Message:" + i)); } } }
运行这个例子会得到下面的输出结果:
Consumer1 get Message:0 Consumer2 get Message:1 Consumer1 get Message:2 Consumer2 get Message:3 Consumer1 get Message:4 Consumer2 get Message:5 Consumer1 get Message:6 Consumer2 get Message:7 Consumer1 get Message:8 Consumer2 get Message:9
可以看出每个消息直被消费了一次,但是如果有多个消费者同时监听一个Queue的话,无法确定一个消息最终会被哪一个消费者消费。
文章来源:http://www.cnblogs.com/guthing/archive/2010/06/12/1757152.html