深入掌握JMS（五）：实战Topic

与Queue不同的是，Topic实现的是发布/订阅模型，在下面的例子中，启动2个消费者共同监听一个Topic，然后循环给这个Topic中发送多个消息。

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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.Session;  
import javax.jms.TextMessage;  
import javax.jms.Topic;  
 
import org.apache.activemq.ActiveMQConnectionFactory;  
import org.apache.activemq.command.ActiveMQTopic;  
 
 
public class TopicTest {  
 
    public static void main(String[] args) throws Exception {  
        ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory("vm://localhost");  
     
        Connection connection = factory.createConnection();  
        connection.start();  
         
        //创建一个Topic  
        Topic topic= new ActiveMQTopic("testTopic");  
        Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);  
          
        //注册消费者1  
        MessageConsumer comsumer1 = session.createConsumer(topic);  
        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(topic);  
        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(topic);  
        for(int i=0; i<10; i++){  
            producer.send(session.createTextMessage("Message:" + i));  
        }  
    }  
 
} 
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.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;

import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.command.ActiveMQTopic;

public class TopicTest {

    public static void main(String[] args) throws Exception {
        ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory("vm://localhost");
  
        Connection connection = factory.createConnection();
        connection.start();
      
        //创建一个Topic
        Topic topic= new ActiveMQTopic("testTopic");
        Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
       
        //注册消费者1
        MessageConsumer comsumer1 = session.createConsumer(topic);
        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(topic);
        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(topic);
        for(int i=0; i<10; i++){
            producer.send(session.createTextMessage("Message:" + i));
        }
    }

}
运行后得到下面的输出结果：

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Consumer1 get Message:0 
Consumer2 get Message:0 
Consumer1 get Message:1 
Consumer2 get Message:1 
Consumer1 get Message:2 
Consumer2 get Message:2 
Consumer1 get Message:3 
Consumer2 get Message:3 
Consumer1 get Message:4 
Consumer2 get Message:4 
Consumer1 get Message:5 
Consumer2 get Message:5 
Consumer1 get Message:6 
Consumer2 get Message:6 
Consumer1 get Message:7 
Consumer2 get Message:7 
Consumer1 get Message:8 
Consumer2 get Message:8 
Consumer1 get Message:9 
Consumer2 get Message:9 
Consumer1 get Message:0
Consumer2 get Message:0
Consumer1 get Message:1
Consumer2 get Message:1
Consumer1 get Message:2
Consumer2 get Message:2
Consumer1 get Message:3
Consumer2 get Message:3
Consumer1 get Message:4
Consumer2 get Message:4
Consumer1 get Message:5
Consumer2 get Message:5
Consumer1 get Message:6
Consumer2 get Message:6
Consumer1 get Message:7
Consumer2 get Message:7
Consumer1 get Message:8
Consumer2 get Message:8
Consumer1 get Message:9
Consumer2 get Message:9
 
说明每一个消息都会被所有的消费者消费。