JMS消息以可靠的方式归档

Question

I'm looking for a way to reliably retrieve messages from a JMS queue and store them into a flat file. By "reliably" I mean that in case of any failure (excluding failures of physical disks), possibly after system and processes are re-launched, I want:

1. to not lose any message and
2. to not have duplicate messages in my file.

What would be a good way for achieving this goal?

Context: WebLogic on Linux, receiving about 3000 messages/second for several hours.

Thanks -- Florian.

Answer 1

The problem you'll face is the file system; JMS supports JTA, but the file system does not. Consider the following:

public void onMessage(Message message){
  try{
    TextMessage msg = (TextMessage)message;
    fileOutput.write( msg.getText());
    fileOutput.flush();

  }catch(Exception e){
    e.printStackTrace();
    throw e;
  }
}

Assuming AUTO_ACKNOWLEDGE, each message received and serialized to the file will be auto acknowledged after onMessage() returns successfully. But the JMS server may crash before the acknowledgment is received, but after the message was written to the file; so you'll get a duplicate.

Instead of writing to a file, have you considered saving to a database, preferably one that has a XA driver? If so, you can use a distributed transaction between JMS and RDBMS, resulting in no message loss or duplicates.

Hope it helps