java - MessageDriverBean - 重试机制

Question

我一直在阅读 SO 和其他一些谷歌结果，我很困惑，有人说我必须调用 context.setRollbackOnly(); 其他人说这不是必需的，因为 MDB 会自己做。

因此，我有一个 MessageDrivenBean 类，它从 JMS 队列 接收消息。

@MessageDriven(name = "MyEventReceiverJMS", activationConfig = {
    @ActivationConfigProperty(propertyName = "destinationLookup", propertyValue = "jms/TheQueue"),
    @ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Queue"),
    @ActivationConfigProperty(propertyName = "acknowledgeMode", propertyValue = "Auto-acknowledge")
})
public class MyEventReceiverJMS implements MessageListener {

    private final Logger logger = LoggerFactory.getLogger(getClass());

    @Resource
    private MessageDrivenContext context;


    @Override
    public void onMessage(Message message) {

        try {
            // Some logic goes here
        } 
        catch (JMSException ex) {
            logger.error("JMSException|could not retrieve object from the message body - reason: {}", ex.getMessage());
            context.setRollbackOnly();
        } 
        catch (JSONException ex) {
            logger.error("error while creating the JSON - reason: ", ex.getMessage());
            context.setRollbackOnly();
        } 
        catch (IOException ex) {
            logger.error("could not communicate with the server - reason: {}", ex.getMessage());
            context.setRollbackOnly();
        }
    }
}

我的问题是，如果onMessage出现异常，消息(或者我称之为事件)是否会被MDB放回队列或者我是否必须在每次捕获时调用 context.setRollbackOnly(); 才能将消息放回？

Answer 1

我是否必须在每次捕获时调用 context.setRollbackOnly() 才能将消息放回？

这取决于我们，如果您想回滚所有异常的消息，是的。 如果它是坏消息/有毒消息，则没有回滚事务的意义，最好通过记录异常和消息的有效负载来丢弃。

对于您的第一个查询，如果 onMessage 出现异常，消息是否会被放回到队列中，请查找以下几点:

The JMS Server could redeliver messages because of:

A java.lang.Error or java.lang.RuntimeException has been thrown from the Receiver/MDB’s onMessage method

User has made a call to ejbcontext.setRollbackOnly() in his MDB’s onMessage method (this applies to Container Managed Transaction only)

MDB participating in a Transaction failed for some reason.

以下帖子非常好，您可以引用以了解更多详细信息:

http://weblogic-wonders.com/weblogic/2011/01/10/working-with-jms-and-the-standard-issues-in-jms/