MessageListener不在Oracle队列中收听消息

Question

我已经实现了Oracle高级队列&我在写一个监听器程序。下面是我的示例：

package com.myprog; 

import java.io.File; 
import java.io.FileInputStream; 
import java.io.StringWriter; 
import java.sql.Connection; 
import java.sql.DriverManager; 
import java.util.Properties; 

import javax.jms.ExceptionListener; 
import javax.jms.JMSException; 
import javax.jms.Message; 
import javax.jms.MessageConsumer; 
import javax.jms.MessageListener; 
import javax.jms.Queue; 
import javax.jms.QueueConnection; 
import javax.jms.QueueConnectionFactory; 
import javax.jms.Session; 
import javax.jms.TextMessage; 

import oracle.jms.AQjmsFactory; 
import oracle.jms.AQjmsSession; 

import org.apache.log4j.Logger; 

public class abc implements MessageListener, ExceptionListener { 
private static String queueUserName = "admin"; 
private static String queueName = "my_queue"; 

// Initialize the logger 
private static Logger log = Logger.getLogger(abc.class); 

public static void main(String[] args) { 
    final String METHOD_NAME = "main()"; 

    abc a = new abc();    

     Queue queue; 
     try { 
     QueueConnection QCon = getConnection(); 
     Session session = QCon.createQueueSession(false, Session.AUTO_ACKNOWLEDGE); 
     QCon.start(); 

     queue = ((AQjmsSession) session).getQueue(queueUserName, queueName); 
     MessageConsumer consumer = session.createConsumer(queue);  

     consumer.setMessageListener(a); 
     QCon.setExceptionListener(a); 

     consumer.close(); 
     session.close(); 
     QCon.close(); 
     } catch (JMSException e) { 
     e.printStackTrace(); 
     }   

} 

public static QueueConnection getConnection() { 
    String hostname = "myhost"; 
    String oracle_sid = "mysid"; 
    int portno = 1521; 
    String userName = "myapp"; 
    String password = "pwd"; 
    String driver = "thin"; 
    QueueConnectionFactory QFac = null; 
    QueueConnection QCon = null; 
    try { 
    // get connection factory , not going through JNDI here 
    QFac = AQjmsFactory.getQueueConnectionFactory(hostname, oracle_sid, portno,driver); 

    // create connection 
    QCon = QFac.createQueueConnection(userName, password); 
    } catch (Exception e) { 
    e.printStackTrace(); 
    } 
    return QCon; 
} 

@Override 
public void onException(JMSException e) { 
    log.error(e);  
} 

@Override 
public void onMessage(Message message) { 
    TextMessage msg = (TextMessage) message; 

    try { 
     String m = msg.getText(); 
     System.out.println("m="+m); 
     log.info("MESSAGE RECEIVED " + m); 
    } catch (JMSException e) { 
     log.error(e); 
    } 
} 

}

请注意，此计划是一个独立的程序将继续运行&听在Oracle队列中的消息。

不幸的是，当我创建这个类文件&来看，它的罐子，它只是运行&然后退出&在队列中仅消耗1消息。为什么听众不能继续在队列中运行&？

我以为它会继续收听&检索队列中的所有消息&然后将永远保持在侦听模式，但它不会那样表现。

欣赏是否有人能告诉我发生了什么问题。

感谢

Answer 1

下面是另一个例子JMS如何循环处理多个消息的示例。

Performs a JNDI lookup of the ConnectionFactory and Destination. 
Creates a Connection and a Session. 
Creates a MessageConsumer: 

consumer = session.createConsumer(dest); 
Starts the connection, causing message delivery to begin: 

connection.start(); 
Receives the messages sent to the destination until the end-of-message-stream control message is received: 

while (true) { 
    Message m = consumer.receive(1); 
    if (m != null) { 
    if (m instanceof TextMessage) { 
     message = (TextMessage) m; 
     System.out.println("Reading message: " + 
     message.getText()); 
    } else { 
     break; 
    } 
    } 
} 

Because the control message is not a TextMessage, the receiving program terminates the while loop and stops receiving messages after the control message arrives. 
Closes the connection in a finally block, automatically closing the session and MessageConsumer. 

你或许能够在while循环中包装这段代码。这取决于JMS如何让您处理连接和会话对象，以及它们是否自动关闭，但您可以尝试包装这一点。

while(true) { 
     QCon.start(); 

     queue = ((AQjmsSession) session).getQueue(queueUserName, queueName); 
     MessageConsumer consumer = session.createConsumer(queue);  

     consumer.setMessageListener(a); 
     QCon.setExceptionListener(a); 

     consumer.close(); 
} 

Answer 2

这都是因为您在启动后立即关闭连接/会话。 YOu需要进程启动一个在JVM中永远运行的守护进程线程。 JMS不负责保持JVM运行。你需要创建一个刚刚睡过的线程来完成这个任务。