Spring Boot Return 204 No-Content When List Is Empty

Spring boot return 204 No-Content when List is empty

I researched a little more and found this, it's closer to what I was looking for, with this I don't need to check if the list is empty to return

Return HTTP 204 on null with spring @RestController

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.

Is this the correct way to return 204 No Content using Spring?

Comparing to 200 response your 204 response has no Content-Length header. Try adding it manually to see if it helps with your application server handling empty response body:

return ResponseEntity.noContent().header("Content-Length", "0").build();

How to return 204 for Null list or objective instead of 200 []

You can use ResponseEntity model please see the following example:

@GetMapping(path = "/getall")
public ResponseEntity<List<User>> findAll() {
  List<User> users = repository.findAll();
  if (CollectionUtils.isEmpty(users)){
    return ResponseEntity.noContent()
        .build();
  }
  return ResponseEntity.ok()
      .body(users);
}

Spring MVC - Automatically return 204 when rest controller response type is void

I was able to implement a solution based on the link provided by Yoshua. I'm not 100% sure on the implementation details, but it's working for me.

This captures the response from all of the controller methods that have a return type of void and changes their HTTP Status to 204.

import org.springframework.core.MethodParameter;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.servlet.mvc.method.annotation.ResponseBodyAdvice;

@ControllerAdvice
public class NoContentControllerAdvice implements ResponseBodyAdvice<Void> {

    @Override
    public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
        if(returnType.getParameterType().isAssignableFrom(void.class)) {
            return true;
        }

        return false;
    }



    @Override
    public Void beforeBodyWrite(Void body, MethodParameter returnType, MediaType mediaType,
            Class<? extends HttpMessageConverter<?>> converterType, ServerHttpRequest request, ServerHttpResponse response) {

        if(returnType.getParameterType().isAssignableFrom(void.class)) {
            response.setStatusCode(HttpStatus.NO_CONTENT);
        }

        return body;
    }
}

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