Why Spring MVC does not allow to expose Model or BindingResult to an @ExceptionHandler?

Question

Situation

I\'m trying to group the code that logs the exceptions and render a nice view in a few methods. At the moment the logic is sometime in the @RequestHand

Answer 1

I ran into to same problem a while ago. The ModelMap or BindingResult are explicitly not listed as supported argument types in the JavaDocs of @ExceptionHandler, so this must have been intentional.

I reckon the reason behind it being that throwing exceptions in general could leave your ModelMap in an inconsistent state. So depending on your situation you might consider

• Explicitly catch the exception to tell Spring MVC that you know what you're doing (you could use the Template pattern to refactor exception handling logic into one single place)
• If you're in control of the exception hierarchy you could hand over the BindingResult to the exception and extract it from the exception later for rendering purposes
• Not throw an exception in the first place, but use some result code (just like BeanValidation does for example)

HTH