Apache Camel:如何存储变量以备后用 [英] Apache Camel: how store variable for later use

问题描述

在使用Spring DSL与Camel一起玩耍"时，我遇到了以下问题.假设预期的消息流如下所示:

while 'playing around' with Camel using Spring DSL, I came across the following problem. Suppose the expected message flow looks like this:

1. 客户端将带有XML正文的HTTP POST消息发送到CAMEL
2. CAMEL将HTTP POST消息代理到服务器，并使用 接收到的XML正文中获取信息(例如:使用XPATH过滤出某个参数)
3. CAMEL收到答复后，CAMEL使用1中接收到的XML正文中的参数向服务器发送HTTP PUT消息.

1. client sends HTTP POST message with XML body to CAMEL
2. CAMEL proxies HTTP POST message towards server, with the URI slightly adapted using info from the received XML body (eg: use XPATH to filter out a certain parameter)
3. after CAMEL has received a reply, CAMEL sends HTTP PUT message towards server, using parameters out of the XML body received in 1

所以像这样:

<route>
   <from uri="...">
   <to uri="...">
   <to uri="...">
 </route>

问题:如何在第1步中将参数存储在Spring DSL中，以便以后在第3步中可以使用它们?

Question: how do I store the parameters in Spring DSL in step 1, so that I can use them later in step 3 ?

因此，我想从步骤1中接收到的消息的XML主体中提取XML参数，并将其放入变量中，然后稍后我可以将其用于编写在步骤3中发送的消息.

So, I would like to extract XML parameters out of the XML body of the message received in step 1 and put them into variables, which I then later on can use to compose the message to be sent in step 3.

为提取参数，我正在考虑使用XPATH.看起来还可以，但是我只是看不到如何将XPATH的输出放入变量中，然后在...(语法??)上使用该变量

For extracting the parameters, I was thinking of using XPATH. That looks ok, but I just don't see how to put the output of the XPATH into a variable and then use that variable later on ... (syntax ??)

注意:如您所见，我的开发知识相当有限，对此感到抱歉.但是，如果有人可以帮助您，这仍然很棒:).

Note: as you can see, my development knowledge is rather limited ... sorry for that. But it would still be great if someone could help with this :).

推荐答案

您可以在

you can set store data in the Exchange properties or message headers like this...

.setHeader("ID", XPathBuilder.xpath("/order/@id", String.class))
.setProperty("ID", XPathBuilder.xpath("/order/@id", String.class))

然后像这样从Exchange在bean/处理器中检索它们...

and then retrieve them in a bean/processor from the Exchange like this...

String propId = (String) exchange.getProperty("ID");
String headerId = (String) exchange.getIn().getHeader("ID");                        }

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