前面讲过JMSCorrelationID主要是用来关联多个Message,例如需要回复一个消息的时候,通常把回复的消息的JMSCorrelationID设置为原来消息的ID。
在下面这个例子中,创建了三个消息生产者A,B,C和三个消息消费者A,B,C。生产者A给消费者A发送一个消息,同时需要消费者A给它回复一个消息。B、C与A类似。
简图如下:
生产者A-----发送----〉消费者A-----回复------〉生产者A 生产者B-----发送----〉消费者B-----回复------〉生产者B 生产者C-----发送----〉消费者C-----回复------〉生产者C
需要注意的是,所有的发送和回复都使用同一个Queue,通过Selector区分。
package com.bijian.study; import javax.jms.*; import org.apache.activemq.ActiveMQConnectionFactory; import org.apache.activemq.command.ActiveMQQueue; public class JMSCorrelationIDTest { private Queue queue; private Session session; public JMSCorrelationIDTest() throws JMSException { ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory("tcp://localhost:61616"); Connection connection = factory.createConnection(); connection.start(); queue = new ActiveMQQueue("testQueue"); session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE); setupConsumer("ConsumerA"); setupConsumer("ConsumerB"); setupConsumer("ConsumerC"); setupProducer("ProducerA", "ConsumerA"); setupProducer("ProducerB", "ConsumerB"); setupProducer("ProducerC", "ConsumerC"); } private void setupConsumer(final String name) throws JMSException { // 创建一个消费者,它只接受属于它自己的消息 MessageConsumer consumer = session.createConsumer(queue, "receiver='" + name + "'"); consumer.setMessageListener(new MessageListener() { public void onMessage(Message m) { try { MessageProducer producer = session.createProducer(queue); System.out.println(name + " get:" + ((TextMessage) m).getText()); // 回复一个消息 Message replyMessage = session.createTextMessage("Reply from " + name); // 设置JMSCorrelationID为刚才收到的消息的ID replyMessage.setJMSCorrelationID(m.getJMSMessageID()); producer.send(replyMessage); } catch (JMSException e) { } } }); } private void setupProducer(final String name, String consumerName) throws JMSException { MessageProducer producer = session.createProducer(queue); producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT); // 创建一个消息,并设置一个属性receiver,为消费者的名字 Message message = session.createTextMessage("Message from " + name); message.setStringProperty("receiver", consumerName); producer.send(message); // 等待回复的消息 MessageConsumer replyConsumer = session.createConsumer(queue, "JMSCorrelationID='" + message.getJMSMessageID() + "'"); replyConsumer.setMessageListener(new MessageListener() { public void onMessage(Message m) { try { System.out.println(name + " get reply:" + ((TextMessage) m).getText()); } catch (JMSException e) { } } }); } public static void main(String[] args) throws Exception { new JMSCorrelationIDTest(); } }
运行结果为:
ConsumerA get:Message from ProducerA ProducerA get reply:Reply from ConsumerA ConsumerB get:Message from ProducerB ProducerB get reply:Reply from ConsumerB ConsumerC get:Message from ProducerC ProducerC get reply:Reply from ConsumerC
文章来源:http://www.cnblogs.com/guthing/archive/2010/06/12/1757179.html