深入掌握JMS（五）：实战Topic

来源：互联网发布：淘宝自定义属性编辑：程序博客网时间：2024/05/18 01:38

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。

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：

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。

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