ActiveMQ消息的发布与订阅

消息的发布与订阅

Publish类

package com.cb01;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.MessageProducer;
import javax.jms.Session;
import javax.jms.TextMessage;
import org.apache.activemq.ActiveMQConnectionFactory;

public class Publish {
	
	//1.连接工厂
	private ConnectionFactory factory;
	//2.连接对象
	private Connection connection;
	//3.Session对象
	private Session session;
	//4.生产者
	private MessageProducer producer;
	
	public Publish(){
		try {
			factory=new ActiveMQConnectionFactory(
					"cb",
					"123456", 
					"tcp://localhost:61616");
			connection=factory.createConnection();
			connection.start();
			session=connection.createSession(Boolean.FALSE, Session.AUTO_ACKNOWLEDGE);
			producer=session.createProducer(null);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	public void send(){
		try {
			Destination destination=session.createTopic("topic1");
			TextMessage textMessage=session.createTextMessage("Publish发布的测试消息");
			producer.send(destination,textMessage);
		} catch (JMSException e) {
			e.printStackTrace();
		}
	}
	
	public static void main(String[] args){
		Publish publish=new Publish();
		publish.send();
	}
	
}

运行上面Publish类，查看ActiveMQ管控台

此时，启动3个Consumer类，分别为ConsumerOne、ConsumerTwo、ConsumerThree。下面以ConsumerOne的代码为例

package com.cb01;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.MapMessage;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.Session;
import javax.jms.TextMessage;
import org.apache.activemq.ActiveMQConnectionFactory;

public class ConsumerOne {

	//1.连接工厂
	private ConnectionFactory factory;
	//2.连接对象
	private Connection connection;
	//3.Session对象
	private Session session;
	//4.消费者
	private MessageConsumer consumer;
	
	public ConsumerOne(){
		try {
			factory=new ActiveMQConnectionFactory(
					"cb",
					"123456",
					"tcp://localhost:61616");
			connection=factory.createConnection();
			connection.start();
			session=connection.createSession(Boolean.FALSE, Session.AUTO_ACKNOWLEDGE);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	public void receiver(){
		try {
			Destination destination=session.createTopic("topic1");
			consumer=session.createConsumer(destination);
			consumer.setMessageListener(new Listener());
		} catch (JMSException e) {
			e.printStackTrace();
		}
	}
	
	class Listener implements MessageListener{

		public void onMessage(Message message) {
			try {
				if(message instanceof TextMessage){
					System.out.println("ConsumerOne："+message);
				}
				
			} catch (Exception e) {
				e.printStackTrace();
			}
			
		}
		
	}
	
    public static void main(String[] args) {
    	ConsumerOne consumer=new ConsumerOne();
    	consumer.receiver();
	}
	
	
}

此时，查看ActiveMQ的控制台。消费者个数为3个，之前的一个消息未被消费，Connection连接个数为4个，分别为1个Publish、3个Consumer与ActiveMQ建立的连接。

此时，再次运行Publish类，并查看ActiveMQ控制台。Message Enqueued由之前的1变为2，Message Dequeued由之前的0变为3，说明三个消费者都对Publish新发送的消息进行了消费。

上图中的5个Connection分别由下图中5个进程建立

同时，在3个Consumer对应的console中均显示接收到的消息内容，下面以ConsumerOne中的内容为例

ConsumerOne：ActiveMQTextMessage {commandId = 5, responseRequired = true, messageId = ID:cb-PC-53237-1514340360647-1:1:1:1:1, originalDestination = null, originalTransactionId = null, producerId = ID:cb-PC-53237-1514340360647-1:1:1:1, destination = topic://topic1, transactionId = null, expiration = 0, timestamp = 1514340360863, arrival = 0, brokerInTime = 1514340360865, brokerOutTime = 1514340360868, correlationId = null, replyTo = null, persistent = true, type = null, priority = 4, groupID = null, groupSequence = 0, targetConsumerId = null, compressed = false, userID = null, content = org.apache.activemq.util.ByteSequence@1b7a12b9, marshalledProperties = null, dataStructure = null, redeliveryCounter = 0, size = 0, properties = null, readOnlyProperties = true, readOnlyBody = true, droppable = false, jmsXGroupFirstForConsumer = false, text = Publish发布的测试消息}