ActiveMQ学习--002--Topic消息例子程序-优快云博客

本文介绍 Java 消息服务 (JMS) 中持久与非持久消息的区别及应用实例，包括非持久消息仅在消费者启动后才能接收消息的特点，以及持久消息即使消费者离线也能接收到所有消息的机制。

一、非持久的Topic消息示例

注意此种方式消费者只能接收到消费者启动之后，发送者发送的消息。

发送者

package com.lhy.mq.helloworld;

import java.util.concurrent.TimeUnit;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.DeliveryMode;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;

import org.apache.activemq.ActiveMQConnectionFactory;

public class NoPersistenceTopicSender {
    
    public static void main(String[] args) throws Exception {
        
        //第一步：建立ConnectionFactory工厂对象。需要填入用户名、密码、连接地址，均使用默认即可，默认端口为"tcp://localhost:61616"
        ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(
                "lhy","123456",
                //ActiveMQConnectionFactory.DEFAULT_USER, 
                //ActiveMQConnectionFactory.DEFAULT_PASSWORD,
                "tcp://127.0.0.1:61616");
        
        Connection connection = connectionFactory.createConnection();
        connection.start();
        Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
        
        Destination destination = session.createTopic("NB-NB"); //队列名称
        
        MessageProducer producer = session.createProducer(null);//
        
        
        // 第六步：可以使用MessageProducer的setDeliveryMode方法为其设置持久化特性和非持久化特性（DeliveryMode）
        //producer.setDeliveryMode(DeliveryMode.NON_PERSISTENT);
        
        for (int i = 0; i < 3; i++) {
            TextMessage message = session.createTextMessage("我是消息内容  -333- "+i);
            producer.send(destination, message);
            
            System.err.println("生产者发送消息："+message.getText()); 
        }
        session.commit();
    
        if(connection != null){
            connection.close();
        }
    }

}

接收者

package com.lhy.mq.helloworld;

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;

import org.apache.activemq.ActiveMQConnectionFactory;

public class NoPersitenceTopicReceiver {

    public static void main(String[] args) throws Exception {
                ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(
                        "lhy","123456",
                        "tcp://localhost:61616");
                Connection connection = connectionFactory.createConnection();
                connection.start();
                final Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
                Destination destination = session.createTopic("NB-NB");
                
                MessageConsumer consumer = session.createConsumer(destination);
                
                Message message = consumer.receive();
                while(message != null){
                    TextMessage textMsg = (TextMessage)message;
                    System.err.println("消费消息："+textMsg.getText());
                    //接收下一个消息
                    message = consumer.receive(1000L);
                }
                
                //提交一下事务，否则不确认消息，消息不会出队列
                session.commit();
                session.close();
                connection.close();
    }
}

二、持久订阅例子程序

发送者

package com.lhy.mq.helloworld;

import java.util.concurrent.TimeUnit;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.DeliveryMode;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;

import org.apache.activemq.ActiveMQConnectionFactory;

public class PersistenceTopicSender {
    
    public static void main(String[] args) throws Exception {
        
        //第一步：建立ConnectionFactory工厂对象。需要填入用户名、密码、连接地址，均使用默认即可，默认端口为"tcp://localhost:61616"
        ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(
                "lhy","123456",
                "tcp://127.0.0.1:61616");
        Connection connection = connectionFactory.createConnection();
        Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
        Topic destination = session.createTopic("Persistence-Topic"); //队列名称
        MessageProducer producer = session.createProducer(null);//
        
        //默认为持久订阅，注意这个一定在start之前设置
        producer.setDeliveryMode(DeliveryMode.PERSISTENT);
        connection.start();
        
        for (int i = 0; i < 3; i++) {
            TextMessage message = session.createTextMessage("我是消息内容  -666- "+i);
            producer.send(destination, message);
            
            System.err.println("生产者发送-topic-消息："+message.getText()); 
        }
        session.commit();
    
        if(connection != null){
            connection.close();
        }
    }

}

消费者，可以有多个消费者

1，消费者需要在Connection上设置消费者id，来识别消费者

2，需要创建TopicSubscriber 来订阅

3，设置好之后再start 这个Connection

4，一定要先运行一次消费者，来向ActiveMQ注册这个消费者，然后再运行发送消息，这样无论消费者是否在线，都会接收到消息。否则只能接收到注册之后的消息。

package com.lhy.mq.helloworld;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.jms.Topic;
import javax.jms.TopicSubscriber;

import org.apache.activemq.ActiveMQConnectionFactory;

/**
 * 消费者需要先运行一次，向producer注册一下
 * @author dell
 *
 */
public class PersitenceTopicReceiver {

    public static void main(String[] args) throws Exception {
                ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(
                        "lhy","123456",
                        "tcp://localhost:61616");
                Connection connection = connectionFactory.createConnection();
                //设置消费者的id，向发送者先注册一下，producer就知道谁在订阅
                connection.setClientID("client2");
                
                final Session session = connection.createSession(Boolean.TRUE, Session.AUTO_ACKNOWLEDGE);
                Topic destination = session.createTopic("Persistence-Topic");
                TopicSubscriber consumer = session.createDurableSubscriber(destination, "T1");//创建一个持久订阅
                //最后start
                connection.start();
                
                Message message = consumer.receive();
                while(message != null){
                    TextMessage textMsg = (TextMessage)message;
                    System.err.println("消费消息："+textMsg.getText());
                    //接收下一个消息
                    message = consumer.receive(1000L);
                }
                
                //提交一下事务，否则不确认消息，消息不会出队列
                session.commit();
                session.close();
                connection.close();
    }
}