我已经建立了一个客户Oracle AQ。我在CLIENT_ACKNOWLEDGE模式的Java Web应用程序中观察到来自此队列的消息。但是,一旦我收到onMessage方法中的消息,这些消息似乎就会从Oracle队列中删除。我的假设是,除非我在客户端中acknowledge消息,否则不应删除该消息。如何停止呢?

Oracle Queue模式如下所示:

BEGIN DBMS_AQADM.CREATE_QUEUE_TABLE(
  Queue_table => '"TESTUSER"."myqueuetable"',
  Queue_payload_type => 'TESTUSER.messageobject',
  multiple_consumers => false
);
END;
/

BEGIN DBMS_AQADM.CREATE_QUEUE(
  Queue_name => 'TESTUSER.myqueue',
  Queue_table => 'TESTUSER.myqueuetable',
  Queue_type => 0, Max_retries => 5, Retry_delay => 0
);
END;
/

BEGIN dbms_aqadm.start_queue (
  queue_name => 'testuser.myqueue'
);
END;


我这样观察我的Java应用程序中的消息

 //somewhere in my app
session = queueConnection.createQueueSession(false, Session.CLIENT_ACKNOWLEDGE);
queueReceiver = ((AQjmsSession) databaseConnectionManager.getSession())
 .createReceiver(databaseConnectionManager.getQueue(), Messageobject.getORADataFactory());
queueReceiver.setMessageListener(this);


//in my listener class
@Override
public void onMessage(Message message) {
 AdtMessage msg = (AdtMessage) message;

 try {
  Messageobject message = (Messageobject) msg.getAdtPayload();

  if (isUserConnected(message.userId)) {
   logger.debug("Message acknowledged");
   msg.acknowledge();
   //handle the message. the message should be deleted now.
  } else {
   //i don't want the message to be deleted
  }

 } catch (JMSException | IllegalArgumentException | SQLException e) {
  logger.error("An error occurred while sending an outgoing blob", e);
 }
}

最佳答案

您正在创建一个使用者队列,该消息在成功使用后将立即删除。

要保留消息,请在创建队列时将tention_time设置为大于零的值。

BEGIN
  DBMS_AQADM.CREATE_QUEUE(
    Queue_name => 'TESTUSER.myqueue',
    Queue_table => 'TESTUSER.myqueuetable',
    Queue_type => 0, Max_retries => 5, Retry_delay => 0,
    retention_time => 300    -- retain for next 5 minutes
  );
END;
/


请参阅https://docs.oracle.com/database/121/ARPLS/d_aqadm.htm#ARPLS109

09-10 05:59
查看更多