传输方式Topic和Queue的对比

本文详细对比了JMS规范中的Topic和Queue两种消息传输方式,包括它们的区别、应用场景、代码实现及消息接收策略。通过实例代码展示了如何使用JMS API与ActiveMQ实现消息的发送和接收,提供了JMS中使用Queue传输消息的代码示例,并解释了确认消息接收的方式。同时,还介绍了JMS中创建Session时的参数设置,以及消息发布接收策略的实现。

Jms规范里的两种message传输方式Topic和Queue,两者的对比如下表():

TopicQueue
概要Publish  Subscribe messaging 发布订阅消息Point-to-Point  点对点
有无状态topic数据默认不落地,是无状态的。

Queue数据默认会在mq服务器上以文件形式保存,比如Active MQ一般保存在$AMQ_HOME\data\kr-store\data下面。也可以配置成DB存储。

完整性保障并不保证publisher发布的每条数据,Subscriber都能接受到。Queue保证每条数据都能被receiver接收。
消息是否会丢失一般来说publisher发布消息到某一个topic时,只有正在监听该topic地址的sub能够接收到消息;如果没有sub在监听,该topic就丢失了。Sender发送消息到目标Queue,receiver可以异步接收这个Queue上的消息。Queue上的消息如果暂时没有receiver来取,也不会丢失。
消息发布接收策略一对多的消息发布接收策略,监听同一个topic地址的多个sub都能收到publisher发送的消息。Sub接收完通知mq服务器一对一的消息发布接收策略,一个sender发送的消息,只能有一个receiver接收。receiver接收完后,通知mq服务器已接收,mq服务器对queue里的消息采取删除或其他操作。

以下是符合Jms1.1规范的使用Queue传输消息的代码,使用Active mq作为Jms的实现,想要更clean的代码,可以考虑将Amq的实现DI:

Java代码 复制代码 收藏代码
  1. public void testMySend() throws JMSException { 
  2.         Connection connection = new ActiveMQConnectionFactory("admin","admin","tcp://localhost:61616").createConnection(); 
  3.             Session session = null
  4.             Queue queue = null
  5.             MessageProducer producer = null
  6.             session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE); 
  7.             queue=session.createQueue("myTest"); 
  8.             producer= session.createProducer(queue); 
  9.             Message msg=session.createTextMessage("hello"); 
  10.             producer.send(msg);       
  11.             producer.close(); 
  12.             session.close(); 
  13.             connection.close(); 
  14.     } 
  15.      
  16.     public void testMyReceive() throws JMSException{ 
  17.         Connection connection = new ActiveMQConnectionFactory("admin","admin","tcp://localhost:61616").createConnection(); 
  18.         Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE); 
  19.         Queue queue = session.createQueue("myTest"); 
  20.         MessageConsumer consumer= session.createConsumer(queue); 
  21.         consumer.setMessageListener(new MyListener()); 
  22.         connection.start(); 
  23.         consumer.close(); 
  24.         session.close(); 
  25.             connection.close(); 
  26.     } 
  27.      
public void testMySend() throws JMSException {
		Connection connection = new ActiveMQConnectionFactory("admin","admin","tcp://localhost:61616").createConnection();
	        Session session = null;
	        Queue queue = null;
	        MessageProducer producer = null;
	        session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
	        queue=session.createQueue("myTest");
	        producer= session.createProducer(queue);
	        Message msg=session.createTextMessage("hello");
	        producer.send(msg);      
	        producer.close();
	        session.close();
	        connection.close();
	}
	
	public void testMyReceive() throws JMSException{
		Connection connection = new ActiveMQConnectionFactory("admin","admin","tcp://localhost:61616").createConnection();
		Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
		Queue queue = session.createQueue("myTest");
		MessageConsumer consumer= session.createConsumer(queue);
		consumer.setMessageListener(new MyListener());
		connection.start();
		consumer.close();
		session.close();
	        connection.close();
	}
	

消费端需要设定一个MessageListener:

Java代码 复制代码 收藏代码
  1. private class MyListener implements MessageListener{ 
  2.         public void onMessage(Message message) { 
  3.         System.out.println("msg start!----------------"); 
  4.         try
  5.             System.out.println(""+((TextMessage)message).getText()); 
  6.         } catch (JMSException e) { 
  7.             e.printStackTrace(); 
  8.         } 
  9.         System.out.println("msg end!----------------"); 
  10.         } 
  11.     } 
private class MyListener implements MessageListener{
		public void onMessage(Message message) {
		System.out.println("msg start!----------------");
		try {
			System.out.println(""+((TextMessage)message).getText());
		} catch (JMSException e) {
			e.printStackTrace();
		}
		System.out.println("msg end!----------------");
		}
	}

以下是符合Jms1.1规范的使用Topic 发送消息的代码:

Java代码 复制代码 收藏代码
  1. public void testMyTopicPublisher() throws JMSException { 
  2.          Connection connection = new ActiveMQConnectionFactory("admin","admin","tcp://localhost:61616").createConnection(); 
  3.             Session session = null
  4.             Topic topic = null
  5.             MessageProducer producer = null
  6.             session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE); 
  7.             topic=session.createTopic("myTopicTest"); 
  8.             producer= session.createProducer(topic); 
  9.             producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT); 
  10.             Message msg=session.createTextMessage("hello and whatever u say");     
  11.             producer.send(msg);   
  12.             producer.close(); 
  13.             session.close(); 
  14.             connection.close(); 
  15.     } 
public void testMyTopicPublisher() throws JMSException {
		 Connection connection = new ActiveMQConnectionFactory("admin","admin","tcp://localhost:61616").createConnection();
	        Session session = null;
	        Topic topic = null;
	        MessageProducer producer = null;
	        session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
	        topic=session.createTopic("myTopicTest");
	        producer= session.createProducer(topic);
	        producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
	        Message msg=session.createTextMessage("hello and whatever u say");    
	        producer.send(msg);  
	        producer.close();
	        session.close();
	        connection.close();
	}

以下是符合Jms1.1规范的使用Topic 接收消息的代码:

Java代码 复制代码 收藏代码
  1. public static void testMyTopicConsumer() throws JMSException, InterruptedException{ 
  2.         Connection connection = new ActiveMQConnectionFactory("admin","admin","tcp://localhost:61616").createConnection(); 
  3.          Session session = connection.createSession(false, Session.CLIENT_ACKNOWLEDGE); 
  4.          Topic topic = session.createTopic("myTopicTest"); 
  5.          MessageConsumer consumer= session.createConsumer(topic); 
  6.          consumer.setMessageListener(new MyListener()); 
  7.          connection.start(); 
  8.     } 
public static void testMyTopicConsumer() throws JMSException, InterruptedException{
		Connection connection = new ActiveMQConnectionFactory("admin","admin","tcp://localhost:61616").createConnection();
		 Session session = connection.createSession(false, Session.CLIENT_ACKNOWLEDGE);
		 Topic topic = session.createTopic("myTopicTest");
		 MessageConsumer consumer= session.createConsumer(topic);
		 consumer.setMessageListener(new MyListener());
		 connection.start();
	}

jms在创建Session时可以有两个参数,第一个参数是是否使用事务,第二个参数是消费者向发送者确认消息已经接收的方式:

Java代码 复制代码 收藏代码
  1. Session session = connection.createSession(false, Session.CLIENT_ACKNOWLEDGE); 
Session session = connection.createSession(false, Session.CLIENT_ACKNOWLEDGE);

确认消息的方式有如下三种:

AUTO_ACKNOWLEDGE(自动通知)

CLIENT_ACKNOWLEDGE(客户端自行决定通知时机)

DUPS_OK_ACKNOWLEDGE(延时//批量通知)

如果使用的是 客户端自行决定通知时机 方式,那么需要在MessageListener里显式调用message.acknowledge()来通知服务器。服务器接收到通知后采取相应的操作。

 

 

转自:

http://longdick.iteye.com/blog/465229

转载于:https://www.cnblogs.com/zhuhongbao/archive/2013/06/09/3128272.html

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