How to add a custom annotation to Spring MVC?

Question

Can anyone explain what I need to do to implement my own annotation that would add functionality to my web requests?

For example:

@Controller
public class MyController {
    @RequestMapping("/abc")
    @RequiresSomeSpecialHandling
    public void handleSecureRequest() {
    }
}

Here @RequiresSomeSpecialHandling would be my own annotation that causes some special work to be done before or after the given web request /abc.

I know that on a very high level I would need to write a bean post processor, scan classes for my annotations, and inject custom mvc interceptors when needed. But are there any shortcuts to simplify this task? Especially for the two examples above.

Thanks in advance,

BTW: If "@RequiresAuth" is only an example, then it is good, but do not reinvent spring security — Ralph, Feb 03 '12 at 11:02
It was just an example - edited my post to make the example more generic. — rustyx, Feb 03 '12 at 20:34

Ralph · Answer 1 · 2012-02-03T11:00:43.273

4

This kind of Annotations, (that add additional functionality when invoking a method) looks like annotations that trigger an AOP Advice.

@see Spring Reference Chapter 7. Aspect Oriented Programming with Spring

The idea is to use the Annotation to trigger the AOP Advice.

like:

@Pointcut("@target(com.example.RequiresAuth)")

edited Feb 03 '12 at 11:00

answered Feb 03 '12 at 10:21

Ralph

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Thanks. Yes, AOP is on my list, but I'd like to try to make an annotation and re-use as much MVC facilities as possible. – rustyx Feb 03 '12 at 10:31
@rustyx: Yes, that was the idea behind: use the Annotation to trigger the AOP Advice, see my extended answer to illustrate it. – Ralph Feb 03 '12 at 11:01
I find `@annotation` to be useful in writing pointcut expressions. – Donal Fellows Feb 03 '12 at 16:01
I don't want `@Pointcut`, I want `@MyOwnAnnotation`. – rustyx Feb 03 '12 at 20:39
@rustyx `@Pointcut` is (one of) aspectJ syntax to define a pointcut – Ralph Feb 03 '12 at 21:44

score 2 · Accepted Answer · answered Feb 13 '12 at 21:51

Depends on what you want to do as a result of @RequiresSomeSpecialHandling. E.g. do you want it to influence request mappings or the invocation of the method (i.e. resolving method arguments, processing the return value)?

The support for annotated classes in Spring 3.1 became much more customizable. You can browse some examples in this repo.

Also keep in mind that a HandlerInterceptor in Spring 3.1 can cast the handler Object to HandlerMethod, which gives you access to the exact method including its annotations. That may be enough for what you need to do.

score -3 · Answer 3 · answered Feb 03 '12 at 15:58

-3

If caching is one of your goals, take a look at the @Cacheable annotation (and its siblings @CachePut, @CacheEvict and @Caching), available as of Spring 3.1.

answered Feb 03 '12 at 15:58

matsev

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Sorry, your answer is useless to me. The @NoCache annotation in my example was about HTTP no-cache, not method cache, and it was just an example anyway. – rustyx Feb 03 '12 at 20:37

How to add a custom annotation to Spring MVC?

3 Answers3