Return HTTP 204 on null with spring @RestController

Question

This returns 200 OK with Content-Length: 0

@RestController public class RepoController {     @RequestMapping(value = "/document/{id}", method = RequestMethod.GET)     public Object getDocument(@PathVariable long id) {        return null;     }  } 

Simply put I'd like it to return 204 No Content on null.

Is there a way to force spring-mvc/rest to return 204 on null not 200? I dont want to change every rest method to return ResponseEntity or something like that, only map null to 204

Answer 1

You can use the @ResponseStatus annotation. This way you can have a void method and you don't have to build a ResponseEntity.

@DeleteMapping(value = HERO_MAPPING) @ResponseStatus(value = HttpStatus.NO_CONTENT) public void delete(@PathVariable Long heroId) {     heroService.delete(heroId); } 

BTW returning 200 when the object exists and 204 otherwise it's a bit unusual regarding API REST design. It's common to return a 404 (not found) when the requested object is not found. And this can be achieved using a ControllerAdvice.

In Spring REST it's better to handle Exceptions with a Exception handler instead of putting logic to decide the response status, etc. This is an example using the @ControllerAdvice annotation: http://www.jcombat.com/spring/exception-handling-in-spring-restful-web-service

Answer 2

Of course yes.

Option 1 :

@RestController public class RepoController {     @RequestMapping(value = "/document/{id}", method = RequestMethod.GET)     public Object getDocument(@PathVariable long id, HttpServletResponse response) {        Object object = getObject();        if( null == object ){           response.setStatus( HttpStatus.SC_NO_CONTENT);        }        return object ;     } } 

Option 2 :

@RestController public class RepoController {     @RequestMapping(value = "/document/{id}", method = RequestMethod.GET)     public Object getDocument(@PathVariable long id) {        Object object = getObject();        if ( null == object ){           return new ResponseEntity<Void>(HttpStatus.NO_CONTENT);        }         return object ;     } } 

Might have typos, but you get the concept.