2

我已经实现了 Oracle 高级队列，并且正在编写一个侦听器程序。以下是我的示例：

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，这个程序是一个独立的程序，它将继续运行并监听 oracle 队列中的消息。

不幸的是，当我创建一个此类文件的 jar 并运行它时，它只是运行然后退出并仅使用队列中的 1 条消息。为什么监听器不继续运行并监听队列？

我认为它会继续侦听并检索队列中的所有消息，然后将永远保持在侦听模式，但它的行为并非如此。

感谢有人能告诉我出了什么问题。

谢谢

4

2 回答 2

2

这完全是因为您在启动后立即关闭连接/会话。你需要这个进程来启动一个在 JVM 中永远运行的守护线程。JMS 不负责保持 JVM 运行。您需要创建一个刚刚睡觉的线程来完成此操作。

于 2012-01-08T19:50:41.590 回答
0

下面是另一个 JMS 示例如何循环处理多条消息的示例。

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.

您可能只需将此代码包装在 while 循环中即可。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，但您可以尝试仅包装它。

while(true) {
       QCon.start();

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

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

       consumer.close();
}
于 2012-01-08T04:16:18.357 回答