ActiveMQ基础

消息队列的作用

为什么使用ActiveMQ，不使用其他工具

下载安装包并启动

http://localhost:8161/admin/ (账号：admin:admin)

Java实现步骤：

// 1.创建连接工厂对象（ConnectionFactory）
ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(URL);
// 2.创建连接对象（Connection）
Connection connection = connectionFactory.createConnection();
// 3.启动连接
connection.start();
// 4.创建session会话，第一参数表示启用事务处理，第二个参数表示启动哪种应答模式，这里启用的是自动应答
Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
// 5.创建目的地（queue/topic）
Queue queue = session.createQueue(QUEUE_NAME);
// 6.创建生产者/消费者
MessageProducer producer = session.createProducer(queue);
// 7.生产/消费消息
producer.send(message);

生产者代码：

public class MQProducer {
    private static final String URL = "tcp://localhost:61616";
    private static final String QUEUE_NAME = "queue-test";
    private static final String TOPIC_NAME = "topic-test";
    
    public static void main(String[] args) throws JMSException {
        ConnectionFactory ConnectionFactory = new ActiveMQConnectionFactory(URL);
        Connection connection = ConnectionFactory.createConnection();
        connection.start();
        
        Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
        Queue destination = session.createQueue(QUEUE_NAME); 
//      Topic destination = session.createTopic(TOPIC_NAME); // Topic消息
        MessageProducer producer = session.createProducer(destination);    
        for(int i = 0; i < 10; i++) {
            TextMessage message = session.createTextMessage("Message" + i);
            producer.send(message);
            System.out.println("Sent message" + i);
        }
        
        producer.close();
        session.close();
        connection.close();
    }
}

消费者代码：

public class MQConsumer {
    private static final String URL = "tcp://localhost:61616";
    private static final String QUEUE_NAME = "queue-test";
    private static final String TOPIC_NAME = "topic-test";
    
    public static void main(String[] args) throws JMSException, InterruptedException {

        ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(URL);
        Connection connection = connectionFactory.createConnection();
        
        // 消费者1 : Queue & Topic Consumer
        connection.start();       
        Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
        Queue destination = session.createQueue(QUEUE_NAME); // Topic destination = session.createTopic(TOPIC_NAME);
        MessageConsumer consumer = session.createConsumer(destination);

        // 消费者2 : Topic Subscriber
//      connection.setClientID("client-test");
//      connection.start();
//      Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
//      Topic destination = session.createTopic(TOPIC_NAME);
//      TopicSubscriber consumer = session.createDurableSubscriber(destination, "subscription-test");
        
        // 接收消息1 ： MessageListener异步接收消息
         consumer.setMessageListener(new MessageListener(){
             @Override
             public void onMessage(Message message) {
                 try {
                     System.out.println("Received " + ((TextMessage) message).getText());
                 } catch (JMSException e) {
                     e.printStackTrace();
                 }
             }            
         });
         Thread.sleep(10000); // 主线程等待一段时间后结束
         
        // 接收消息2 ： receive同步阻塞等待消息
//      for(int i = 0; i < 10; i++) {
//          TextMessage message = (TextMessage) consumer.receive();
//          System.out.println("Received " + message.getText());
//      }
        
        consumer.close();
        session.close();
        connection.close();
    }
}

Producer consumer receive messageListener

topic

queue

JMS

消息可靠性之持久化  JDBC

topic持久化

事务

签收

点对点发布订阅

spring整合activemq

zookeeper+replicated levelDB

异步投递

延迟投递

定时投递

重试机制

死信队列

防止重复调用