深入掌握JMS（四）：实战Queue

本文转自： http://blog.csdn.net/iamfafa/article/details/6264587

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。

import javax.jms.Connection; 
import javax.jms.DeliveryMode; 
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("vm://localhost"); 
        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。