tomcat启动时如何启动ActiveMQ？

Question

如何配置我的 J2EE 应用程序以便我可以调用 ActiveMQ 服务和 tomcat 服务器？我知道嵌入式代理，这里询问如何在我启动 tomcat 时启动 ActiveMQ

当前代码（工作正常）： 现在想去掉main()方法，在tomcat运行时使用代码运行。

public class JMSService {


public void produceJMS() throws NamingException, JMSException {

    ConnectionFactory connFactory =  new ActiveMQConnectionFactory(ActiveMQConnection.DEFAULT_BROKER_URL);

    Connection conn = connFactory.createConnection();

    conn.start();

    Session session = conn.createSession(false,Session.AUTO_ACKNOWLEDGE);

    Destination destination = session.createQueue("testQueue");

    MessageProducer producer = session.createProducer(destination);
    producer.setDeliveryMode(DeliveryMode.PERSISTENT);

    TextMessage message = session.createTextMessage("Test Message ");

    // send the message
    producer.send(message);

    System.out.println("sent: " + message);
}}

这是我的消费者：

 public class JMSReceiver implements MessageListener,ExceptionListener {

public static void main(String args[]) throws Exception {

    JMSReceiver re = new JMSReceiver();
    re.receiveJMS();    
  }

 public void receiveJMS() throws NamingException, JMSException {

     ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(ActiveMQConnection.DEFAULT_BROKER_URL);
     Connection connection = connectionFactory.createConnection();
     connection.start();


     Session session = connection.createSession(false,Session.AUTO_ACKNOWLEDGE);

     // Getting the queue 'testQueue'
     Destination destination = session.createQueue("testQueue");


     MessageConsumer consumer = session.createConsumer(destination);         

    // set an asynchronous message listener
    JMSReceiver asyncReceiver = new JMSReceiver();
    consumer.setMessageListener(asyncReceiver);

     connection.setExceptionListener(asyncReceiver);

}

@Override
public void onMessage(Message message) {

    System.out.println("Received message : " +message);
}

}

Answer 1

@Tim Bish 所说的是正确的。您要么需要一个计时器，例如接收器应该监听 1 小时，要么让它在程序终止之前可用。无论哪种情况，您都需要启动一次消费者计划：

如下改变你的receiveJMS方法：

 public void receiveJMS() throws NamingException, JMSException {
try{
     ConnectionFactory connectionFactory = new ActiveMQConnectionFactory(ActiveMQConnection.DEFAULT_BROKER_URL);
     Connection connection = connectionFactory.createConnection();
     connection.start(); // it's the start point


     Session session = connection.createSession(false,Session.AUTO_ACKNOWLEDGE);

     // Getting the queue 'testQueue'
     Destination destination = session.createQueue("testQueue");


     MessageConsumer consumer = session.createConsumer(destination);         

    // set an asynchronous message listener
   // JMSReceiver asyncReceiver = new JMSReceiver(); 
   //no need to create another object
    consumer.setMessageListener(this);

     connection.setExceptionListener(this);

     // connection.close(); once this is closed consumer no longer active

    Thread.sleep(60 *60 * 1000);             // receive messages for 1 hour
   }finally{
      connection.close();// after 1 hour close it
   }

}

上述程序最多可收听 1 小时。如果您希望它只要程序运行，请删除 finally 块。但推荐的方法是以某种方式关闭它。由于您的应用程序似乎是独立的，您可以查看java runtime shutdown hook，您可以在其中指定如何在程序终止时释放这些资源。

如果您的使用者是 Web 应用程序，您可以在 ServletContextlistner 中关闭它。

Answer 2

您没有给消费者应用程序任何时间来实际接收消息，而是创建它，然后关闭它。您要么需要使用定时接收调用来同步接收来自队列的消息，要么需要在主方法中添加某种等待，例如 CountDownLatch 等，以允许异步 onMessage 调用在处理后触发关闭消息已完成。