Spring REST：在发送之前修改响应

Question

I'm using Spring and RepositoryRestResource to create a REST server. I store image names in the database and this is returned in the rest response. I'd like to send back the entire URL instead of just the image name.

For example, when running locally, the response should be:

{
  image: 'http://localhost:8080/img/products/1.jpg'
}

and when deploying to production, the response should be

{
  image: 'http://prod-server.com/img/products/1.jpg'
}

What I currently get is:

{
  image: '1.jpg'
}

The code is exactly what is here: https://github.com/spring-projects/spring-boot/tree/master/spring-boot-samples/spring-boot-sample-data-rest except that I have my own Models

Answer 1

I have just encountered the same problem and learned that ResponseBodyAdvice can be used:

@RestControllerAdvice
public class ResponseAdvice implements ResponseBodyAdvice {

@Override
    public boolean supports(MethodParameter returnType, Class converterType) {
        return returnType.getParameterType().isAssignableFrom(ResponseEntity.class);
    }

    @Override
    public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType, Class selectedConverterType, ServerHttpRequest request, ServerHttpResponse response) {

        return body; // You can modify and return whatever you want.
    }
}

Body object contains your return type from rest endpoint, you can cast it and modify it as you like.