Update docs for ControllerAdvice

In 5.3 it became possible to handle exceptions from any handler through
ExceptionHandler's in a ControllerAdvice class, but this is not
mentioned in the docs

See gh-22619, gh-27338
This commit is contained in:
Rossen Stoyanchev 2021-09-24 15:57:15 +01:00
parent e29cfa3501
commit 93f8706dd3
1 changed files with 16 additions and 18 deletions

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@ -4021,27 +4021,25 @@ necessary methods, and declare it as a Spring bean.
=== Controller Advice
[.small]#<<web-reactive.adoc#webflux-ann-controller-advice, WebFlux>>#
Typically `@ExceptionHandler`, `@InitBinder`, and `@ModelAttribute` methods apply within
the `@Controller` class (or class hierarchy) in which they are declared. If you want such
methods to apply more globally (across controllers), you can declare them in a class
annotated with `@ControllerAdvice` or `@RestControllerAdvice`.
`@ExceptionHandler`, `@InitBinder`, and `@ModelAttribute` methods apply only to the
`@Controller` class, or class hierarchy, in which they are declared. If, instead, they
are declared in an `@ControllerAdvice` or `@RestControllerAdvice` class, then they apply
to any controller. Moreover, as of 5.3, `@ExceptionHandler` methods in `@ControllerAdvice`
can be used to handle exceptions from any `@Controller` or any other handler.
`@ControllerAdvice` is annotated with `@Component`, which means such classes can be
registered as Spring beans through <<core.adoc#beans-java-instantiating-container-scan,
component scanning>>. `@RestControllerAdvice` is a composed annotation that is annotated
with both `@ControllerAdvice` and `@ResponseBody`, which essentially means
`@ExceptionHandler` methods are rendered to the response body through message conversion
(versus view resolution or template rendering).
`@ControllerAdvice` is meta-annotated with `@Component` and therefore can be registered as
a Spring bean through <<core.adoc#beans-java-instantiating-container-scan,
component scanning>>. `@RestControllerAdvice` is meta-annotated with `@ControllerAdvice`
and `@ResponseBody`, and that means `@ExceptionHandler` methods will have their return
value rendered via response body message conversion, rather than via HTML views.
On startup, the infrastructure classes for `@RequestMapping` and `@ExceptionHandler`
methods detect Spring beans annotated with `@ControllerAdvice` and then apply their
methods at runtime. Global `@ExceptionHandler` methods (from a `@ControllerAdvice`) are
applied _after_ local ones (from the `@Controller`). By contrast, global `@ModelAttribute`
and `@InitBinder` methods are applied _before_ local ones.
On startup, `RequestMappingHandlerMapping` and `ExceptionHandlerExceptionResolver` detect
controller advice beans and apply them at runtime. Global `@ExceptionHandler` methods,
from an `@ControllerAdvice`, are applied _after_ local ones, from the `@Controller`.
By contrast, global `@ModelAttribute` and `@InitBinder` methods are applied _before_ local ones.
By default, `@ControllerAdvice` methods apply to every request (that is, all controllers),
but you can narrow that down to a subset of controllers by using attributes on the
annotation, as the following example shows:
The `@ControllerAdvice` annotation has attributes that let you narrow the set of controllers
and handlers that they apply to. For example:
[source,java,indent=0,subs="verbatim,quotes",role="primary"]
.Java