Until successful failure expression that checks for multiple types of exceptions

问题

In Mule, I'm using an until successful around an HTTP endpoint, to catch connection exceptions/timeouts. I'm catching 3 different Java exceptions:

• java.net.ConnectException
• java.net.SocketTimeoutException
• java.net.SocketException

I want to put the catching of these 3 into a failureExpression in my until-successful block, however when I try to do something like

• #[exception-type:XYZ || exception-type:ZYX]
• #[exception-type:XYZ] || #[exception-type:ZYX]

I get an error that it cannot parse these. Is there any way I can specify for the failureExpression to check for multiple exception types?

回答1:

I was able to achieve what I wanted using this:

failureExpression="#[exception != null && (exception.causedBy(java.net.ConnectException) || exception.causedBy(java.net.SocketTimeoutException) || exception.causedBy(java.net.SocketException))]"

My problem was the exception in the failure expression could be null, so I had to perform a null check.

回答2:

This is not correct MEL syntax. It should be something like #[exception is Type1 || exception is Typ2].

See:

• http://www.mulesoft.org/documentation/display/current/Mule+Expression+Language+MEL
• http://mvel.codehaus.org/MVEL+2.0+Operators

来源：https://stackoverflow.com/questions/20505855/until-successful-failure-expression-that-checks-for-multiple-types-of-exceptions