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

user_3225260 0
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I'm trying to have spring automatically return HTTP Status 204 when the controller method response type is void. Ex:

Let's say I have a controller method like this:

@DeleteMapping(value = "/{heroId}")
public void delete(@PathVariable Long heroId) {
    heroService.delete(heroId);
}

I'm looking for a way to automatically return 204 without having to annotate the method with @ResponseStatus(value = HttpStatus.NO_CONTENT).

Is it possible to do this with a handler or AOP or some other facility?

PS. I see this answer, Return HTTP 204 on null with spring @RestController, but does not answer my specific question on how this can be implemented for methods with a void return type. Also, this method should work with a method that has no input arguments.

spring-mvc spring java
2 Answers

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;
    }
}
user_32252600

I see this has already been answered, but this solution is a little cleaner:

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) {
    return returnType.getParameterType() == void.class;
  }

  @Override
  public Void beforeBodyWrite(Void body, MethodParameter returnType, MediaType selectedContentType,
      Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {
    response.setStatusCode(HttpStatus.NO_CONTENT);
    return body;
  }
}
user_2558300
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