Have ExceptionHandlerMethodResolver use most-specific ExceptionHandler method [SPR-11016]

[spring-projects-issues]

Deejay opened SPR-11016 and commented

It'd be good to have exceptions handled by the @ExceptionHandler with the most specific exception type defined. At the moment, it appears to be handled by whichever handler it finds first that can deal with any type in the exception's ancestry.

Jersey's similar ExceptionMapper mechanism iterates over each handler, then iterates up the type ancestry of the exception, counting as it goes. The handler with the shortest distance between the exception's actual type and the handled type wins and is returned. This could be cached for efficiency.

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Reference URL: http://stackoverflow.com/questions/19498378/setting-precedence-of-multiple-controlleradvice-exceptionhandlers/19500823

[spring-projects-issues]

Rossen Stoyanchev commented

The logic for selecting @ExceptionHandler methods is using org.springframework.core.ExceptionDepthComparator (this is from ExceptionHandlerMethodResolver) so if you have two methods, the one with the more specific exception should be selected.

Can you provide a concrete example? A executable example would be best but code snippets of controller and exception handling method signatures would be okay as well.

[spring-projects-issues]

Deejay commented

Hi, I've raised a pull request for the Spring Framework Issues repo with a small project that demonstrates the issue.

There are three tests in ExceptionHandlerTest. exceptionHandledByCatchAll should pass, and the other two (uncheckedExceptionHandled and checkedExceptionHandled) should fail, as those @ExceptionHandlers are never invoked.

BTW Maven didn't pick up the tests on the command line, but did through STS.

[spring-projects-issues]

Rossen Stoyanchev commented

Thanks for the example! The tests pass for me but despite that they show me exactly what you mean.

The feature was designed to work like this. The first @ControllerAdvice to return an exception handling method "wins". You can order them by adding @Order or implementing Ordered.

On a related note we have also recently added more fine-grained control over what controllers an @ControllerAdvice applies to (see #14855).

I'd be interested to know if your use case can be served by the above?

[spring-projects-issues]

Bulk closing outdated, unresolved issues. Please, reopen if still relevant.