實戰Topic

與Queue不同的是，Topic實現的是發佈/訂閱模型，在下面的例子中，啓動2個消費者共同監聽一個Topic，然後循環給這個Topic中發送多個消息。

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
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.ActiveMQConnection;
import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.command.ActiveMQTopic;

public class TopicTest {

/**
* @param args
* @throws JMSException
*/
public static void main(String[] args) throws JMSException {
// TODO Auto-generated method stub
// ConnectionFactory ：連接工廠，JMS 用它創建連接
ConnectionFactory factory = new ActiveMQConnectionFactory(ActiveMQConnection.DEFAULT_USER
, ActiveMQConnection.DEFAULT_PASSWORD, "tcp://127.0.0.1:61616");
//JMS 客戶端到JMS Provider 的連接
Connection connection = factory.createConnection();
connection.start();
// Session： 一個發送或接收消息的線程
Session session = connection.createSession(Boolean.FALSE, Session.AUTO_ACKNOWLEDGE);
// Destination ：消息的目的地;消息發送給誰.
// 獲取session注意參數值my-queue是Query的名字
Topic topic = new ActiveMQTopic("topicTest");

MessageConsumer comsumer1 = session.createConsumer(topic);
comsumer1.setMessageListener(new MessageListener() {

public void onMessage(Message message) {
// TODO Auto-generated method stub
try {
System.out.println("Consumer 1 get " + ((TextMessage)message).getText());
} catch (Exception e) {
e.printStackTrace();
}
}
});


MessageConsumer comsumer2 = session.createConsumer(topic);
comsumer2.setMessageListener(new MessageListener() {

public void onMessage(Message message) {
// TODO Auto-generated method stub
try {
System.out.println("Consumer 2 get " + ((TextMessage)message).getText());
} catch (Exception e) {
e.printStackTrace();
}
}
});

MessageProducer producer = session.createProducer(topic);
for (int i=0; i<10; i++) {
producer.send(session.createTextMessage("Message：" + i));
}

}
}


運行後得到下面的輸出結果：
Consumer 1 get Message：0
Consumer 2 get Message：0
Consumer 1 get Message：1
Consumer 2 get Message：1
Consumer 1 get Message：2
Consumer 2 get Message：2
Consumer 1 get Message：3
Consumer 2 get Message：3
Consumer 1 get Message：4
Consumer 2 get Message：4
Consumer 1 get Message：5
Consumer 2 get Message：5
Consumer 1 get Message：6
Consumer 2 get Message：6
Consumer 1 get Message：7
Consumer 2 get Message：7
Consumer 1 get Message：8
Consumer 2 get Message：8
Consumer 1 get Message：9
Consumer 2 get Message：9


說明每一個消息都會被所有的消費者消費。