Exchange.getIn().getBody() 在第二次调用时返回骆驼中的空字符串 [英] Exchange.getIn().getBody() returns empty string in camel on second call

问题描述

我有 2 个相同的电话:

I have 2 identical calls:

String msg1 = exchange.getIn().getBody(String.class);
String msg2 = exchange.getIn().getBody(String.class);

在 msg1 中我得到了正确的期望值，但 msg2 是一个空字符串.我没有设置 Out 消息，所以交换 In 消息应该仍然完整.请解释为什么会发生这种情况.

In msg1 I get the correct expected value , but msg2 is an empty string. I'm not setting the Out message , so the exchange In message should be still intact. Please explain why this is happening.

骆驼路线:

<camelContext xmlns="http://camel.apache.org/schema/spring">
    <route id="route1">
        <from uri="timer://myTimer?period=2000" />
        <setBody>
            <simple>Hello World ${header.firedTime}</simple>
        </setBody>
        <process ref="messageProcessor" />
        <to uri="http://localhost:8090"/>
    </route>
    <route id="route2">
        <from uri="jetty://http://localhost:8090" />
        <process ref="messageProcessor" />
    </route>
</camelContext>

处理器只包含上面的 2 条语句.route1 中的处理是正确的，但在 route2 中我得到了描述的行为:第一次调用 - 有效字符串，第二次调用 - 空字符串.所以我觉得可能跟HttpMessage的转换有关系.

The processor contains only the 2 statements from above. The processing in route1 is correct , but in route2 I get the described behaviour : first call - valid string , second call - empty string. So I think maybe it has something to do with HttpMessage conversion.

推荐答案

来自 http://camel.apache.org/jetty.html

Jetty 是基于流的，这意味着它接收到的输入被提交以骆驼为流.这意味着您将只能阅读流的内容一次.

Jetty is stream based, which means the input it receives is submitted to Camel as a stream. That means you will only be able to read the content of the stream once.

在使用两次或更多次之前只需将输入转换为字符串

Just convert the input in a String before use it twice or more times

<route id="route2">
    <from uri="jetty://http://localhost:8090" />
    <convertBodyTo type="String" />
    <process ref="messageProcessor" />
</route>

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