Inconsistent interpretation of parameter annotations in interface-based handler methods [SPR-14021]

[spring-projects-issues]

Paul opened SPR-14021 and commented

If I have Spring MVC interface with methods, whose params are annotated with different param types like this:

public interface PersonAPIEndpoint {
  @RequestMapping(
      path = "/person/{username}/",
      method = RequestMethod.GET
  )
  DeferredResult<PersonWithOrganizationalUnitsDTO> loadUserByUsername(@PathVariable("username") String username);

  @RequestMapping(
      path = "/person",
      method = RequestMethod.GET
  )
  DeferredResult<DataPage<PersonDTO>> listPersons(@RequestParam("pageNum") int pageNum, @RequestParam("pageSize") int pageSize, @RequestParam(value = "query", required = false) String query);

and class, which is derived from this interface, but arguments of methods are not annotated with Param annotations mapper behaviour is inconsistent:
values, annotated with @RequestParam get their values in implementing class, and with @PathVariable — not.

---

Issue Links:

• Enable REST controller method parameter annotations on an interface [SPR-11055] #15682 Enable REST controller method parameter annotations on an interface ("duplicates")

Referenced from: commits spring-attic/spring-framework-issues@bfbb943, spring-attic/spring-framework-issues@de6f178

[spring-projects-issues]

Greg Turnquist commented

Moved to Spring Framework since this involves Spring MVC.

[spring-projects-issues]

Paul commented

I'm sorry, didn't know where to post it to.
Thank you for your help.

[spring-projects-issues]

Rossen Stoyanchev commented

Annotations on method parameters are expected to be in the implementing class. I'm not sure why @RequestParam works. Could you provide a sample project (the repro repository might help)?

[spring-projects-issues]

Paul commented

Now, when Spring Cloud project exists — it's good idea to have single interface for endpoint and FeignClient, because client is declarative and is being build depending on annotations.

[spring-projects-issues]

Paul commented

Reproduce tests in pull request: spring-attic/spring-framework-issues#120

[spring-projects-issues]

Rossen Stoyanchev commented

Sorry for not seeing this right away but @RequestParam is the default for simple types. As long as the method argument name matches the request parameter name, it just works and the annotation doesn't have to be present. In other words you can remove those annotations and it would still work.

[spring-projects-issues]

Rossen Stoyanchev commented

Resolving as duplicate of #15682.