动态SendTo批注 [英] Dynamic SendTo annotation

问题描述

我有以下Java代码，用于从队列接收消息，对其进行处理并将已处理的消息写入另一个队列.

I have Java code as following to receive messages form a queue, process it and write processed message to another queue.

    @RabbitListener(queues = "rawFusion")
    @SendTo("Fusion")
    public String receiverFusion(Object _message) {
        String message = getMessage(_message);
        return messageParser.parse(message);
    }

在这里，我总是从"rawFusion"队列中获取消息，并将其写入"Fusion"队列中.

Here i always get messages from "rawFusion" queue and write it into "Fusion" queue.

我要做的是根据某些条件将消息写入不同的队列.因此，我想在收到来自"RawFusion"队列的消息后决定@SendTo参数(或者可能不使用@SendTo).

The thing I want to do is, writing messages different queues depending on some conditions. So i would like decide @SendTo parameter (or maybe without using @SendTo) after i receive message from the "RawFusion" queue.

有什么想法吗?

预先感谢

推荐答案

如果发件人设置了replyTo消息属性(队列名称或exchange/routkingKey)，则容器将使用该属性. @SendTo仅在消息中没有replyTo时使用.

If the sender sets the replyTo message property (either a queue name or exchange/routkingKey), the container will use that. The @SendTo is only used if there's not replyTo in the message.

如果您不能更改发送者，则在使用@RabbitListener时，@SendTo可以包含SpEL表达式，但是它没有请求中的任何上下文，我怀疑您需要智能地路由答复.

If you can't change the sender, when using @RabbitListener, the @SendTo can contain a SpEL expression but it doesn't have any context from the request, which I suspect you would need to intelligently route the reply.

您可以将某些内容存储在ThreadLocal中并使用

You could store something in a ThreadLocal and use

@SendTo("#{someBean.someMethod()}")

找回它.

我将打开一个JIRA问题，看看我们是否可以提出一种为评估提供一些上下文(例如输入参数)的机制.

I will open a JIRA issue to see if we can come up with a mechanism to provide some context (e.g. input arguments) to the evaluation.

编辑

从1.6版开始， @SendTo可以是SpEL表达式，可以在运行时根据请求和回复进行评估. @SendTo("!{'some.reply.queue.with.' + result.queueName}")

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