java - Mule: getting a hold of the exception message

Question

I have a default catch exception in Mule, and I'm trying to get access to the exception message, using a Mule expression: #[exception]

This doesn't seem to work, and I'm guessing that I'm trying to access the wrong variable? I'm trying to log it using logger and also run a custom component that takes in an exception message (as a string.)

Thanks,

Answer 1

在某些情况下exception.cause可能是null，因此建议使用条件来显示消息：

[(exception.cause!=null)?(exception.cause.message):exception]

这将防止空指针异常。

Answer 2

获取异常消息（空安全）的最佳方法是：

#[exception.cause.?message or exception.cause]

Answer 3

你可以这样#[exception.causedBy]做

   <choice-exception-strategy>
        <catch-exception-strategy when="exception.causedBy(com.company.BusinessException)"> <!-- [1] -->
            <jms:outbound-endpoint queue="dead.letter">
                <jms:transaction action="ALWAYS_JOIN" />
            </jms:outbound-endpoint>
        </catch-exception-strategy>
        <rollback-exception-strategy when="exception.causedBy(com.company.NonBusinessException)"> <!-- [2] -->
            <logger level="ERROR" message="Payload failing: #[payload]"/>
        </rollback-exception-strategy>
    </choice-exception-strategy>

更多细节在这里

Answer 4

嗨，如果您想使用 MEL 获取异常消息，您也可以（在捕获异常策略中）使用以下表达式。

#[exception.cause.message]

Answer 5

exception.cause 可以为 null，因此可以这样处理：

#[exception.?cause.message or exception]