JMS学习笔记（2）-ActiveMQ实现

JMS是一种java消息服务规范，ActiveMQ是其中的一种实现

1.实现point-to-point发送消息

消息发送者：Producer.java

package com.itao.study.mq.active;import javax.jms.Connection;import javax.jms.ConnectionFactory;import javax.jms.Destination;import javax.jms.JMSException;import javax.jms.Message;import javax.jms.MessageProducer;import javax.jms.Session;/** * 1.创建Connection Factory； * 2.创建Connection； * 3.创建Session； * 4.创建Message； * 5.创建Destination; * 6.创建MessageProducer/MessageConsumer *  * @author Administrator * */public class Producer {public static void main(String[] args) {ConnectionFactory connectionFactory;//连接工厂Connection connection=null;//连接Session session;//会话Message message;//消息Destination destination;//消息目的地MessageProducer producer;//消息生产者//初始化连接工厂connectionFactory=new org.apache.activemq.ActiveMQConnectionFactory("admin","admin", "tcp://localhost:61616");try{connection = connectionFactory.createConnection();connection.start();//开启连接//false 不启用事物  true 启用事物，此时第二个参数失效//第二个参数是确认方式session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);destination = session.createQueue("test");//创建一个队列producer = session.createProducer(destination);//创建一个消息message = session.createTextMessage("Hello World");//发送消息producer.send(message);//若是事物提交需要session.commit()，否则不需要下面这句话//session.commit();}catch(Exception e){e.printStackTrace();}finally{if(connection !=null){try {connection.close();} catch (JMSException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}}}

消息消费者：Consumer.java

package com.itao.study.mq.active;import javax.jms.Connection;import javax.jms.ConnectionFactory;import javax.jms.Destination;import javax.jms.Message;import javax.jms.MessageConsumer;import javax.jms.Session;import javax.jms.TextMessage;public class Consumer {public static void main(String[] args){ConnectionFactory connectionFactory;//连接工厂Connection connection=null;//连接Session session;//会话Message message;//消息Destination destination;//消息目的地MessageConsumer consumer;//消息消费者//初始化连接工厂connectionFactory=new org.apache.activemq.ActiveMQConnectionFactory("admin","admin", "tcp://localhost:61616");try{connection = connectionFactory.createConnection();connection.start();session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);destination = session.createQueue("test");//创建消费者consumer = session.createConsumer(destination);while(true){TextMessage text= (TextMessage)consumer.receive();if(text!=null){System.out.println("收到消息："+text.getText());}}}catch(Exception e){e.printStackTrace();}}}

第二种方式不用上面的Consumer，也可以采用MessageLister的形式实现监听

MyLister.java

package com.itao.study.mq.active;import javax.jms.JMSException;import javax.jms.Message;import javax.jms.MessageListener;import javax.jms.TextMessage;public class MyLister implements MessageListener{@Overridepublic void onMessage(Message message) {try {System.out.println("我是消费者采用监听器形式实现,收到消息："+((TextMessage) message).getText());} catch (JMSException e) {e.printStackTrace();}}}

在这里我们把消费者改一下，采用监听器的形式实现消息处理

package com.itao.study.mq.active;import javax.jms.Connection;import javax.jms.ConnectionFactory;import javax.jms.Destination;import javax.jms.Message;import javax.jms.MessageConsumer;import javax.jms.Session;import javax.jms.TextMessage;public class Consumer_Lister {public static void main(String[] args){ConnectionFactory connectionFactory;//连接工厂Connection connection=null;//连接Session session;//会话Message message;//消息Destination destination;//消息目的地MessageConsumer consumer;//消息消费者//初始化连接工厂connectionFactory=new org.apache.activemq.ActiveMQConnectionFactory("admin","admin", "tcp://localhost:61616");try{connection = connectionFactory.createConnection();connection.start();session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);destination = session.createQueue("test");//创建消费者consumer = session.createConsumer(destination);//采用监听器形式实现,经测试发现在监听器中不需要实现while,是一直监听的consumer.setMessageListener(new MyLister());}catch(Exception e){e.printStackTrace();}}}

2.实现Publish/Subscribe实现消息传递

消息生产者：Producer_Toptic.java

package com.itao.study.mq.active;import javax.jms.Connection;import javax.jms.ConnectionFactory;import javax.jms.DeliveryMode;import javax.jms.Destination;import javax.jms.Message;import javax.jms.MessageProducer;import javax.jms.Session;import org.apache.activemq.ActiveMQConnectionFactory;public class Producer_Topic {public static void main(String[] args){ConnectionFactory connectionFactory;Connection connection=null;Session session;Destination destination;Message message;MessageProducer producer;connectionFactory=new ActiveMQConnectionFactory("admin","admin","tcp://localhost:61616");try{connection = connectionFactory.createConnection();connection.start();session=connection.createSession(false, Session.AUTO_ACKNOWLEDGE);destination = session.createTopic("testTopic");message=session.createTextMessage("我是消息生产者，topic");producer=session.createProducer(destination);//producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);//设置是否持久化消息;默认是持久化的producer.send(message);//producer.send(session.createTextMessage("nimei啦"));}catch(Exception e){e.printStackTrace();}}}

消息消费者：Consumer_Topic.java

package com.itao.study.mq.active;import javax.jms.Connection;import javax.jms.ConnectionFactory;import javax.jms.Destination;import javax.jms.MessageConsumer;import javax.jms.Session;import javax.jms.TextMessage;import org.apache.activemq.ActiveMQConnectionFactory;public class Consumer_Topic {public static void main(String[] args){ConnectionFactory connectionFactory;Connection connection=null;Session session;Destination destination;MessageConsumer consumer;connectionFactory=new ActiveMQConnectionFactory("admin","admin","tcp://localhost:61616");try{connection = connectionFactory.createConnection();connection.start();session=connection.createSession(false, Session.AUTO_ACKNOWLEDGE);destination=session.createTopic("testTopic");//destination=session.createQueue("testTopic");consumer=session.createConsumer(destination);System.out.println("start receive message...");//consumer.setMessageListener(new MessageListener() {////@Override//public void onMessage(Message message) {////try {//System.out.println("我是topic消费者:"+((TextMessage)message).getText());//} catch (JMSException e) {//// TODO Auto-generated catch block//e.printStackTrace();//}//}//});////用while接收消息试一下while(true){TextMessage text= (TextMessage)consumer.receive();if(text!=null){System.out.println("收到消息："+text.getText());}}}catch(Exception e){e.printStackTrace();}}}

小结：

JMS存在两种消息传递类型，一种是Queue形式，一种是Topic形式

1.在Queue形式中，先开运行Producer，消息会传递到Queue中，若设置了持久化，则在服务器重启后Queue不会消失，在启动Consumer的时候，会从Queue中取出消息。

这也再一次证明，Queue消息，消息生产者和消费者没有时间上的联系。

2.在Topic形式中，消息是传递到Topic中保存的，同样也可以设置持久化，在创建发送者 session.crateProduce(destination)后可以设置是否持久化（默认是持久化的）。

如果先开启Producer，消息同样会传到Topic中，若是此时在开启Consumer，是收不到在Topic中已经存在的消息的；只能在Consumer启动后才能收到此时之后Producer发送的消息。这也证明了，Topic类型消息，生产者和消费者是存在时间上的一致性的。

3.关于这两点大家可以用web控制界面看到实时效果：http://localhost:8161/admin/topics.jsp