Spring + Jackson: Wrapping Response Body in response object

Question

This may be a strange question, although I wonder why it hasn't been asked or proposed before... so please correct me if any ignorance.

First off, I am using Jackson in conjunction with Spring and the @ResponseBody annotation. Currently, for every request handler I am returning a "Response" wrapper object, as that is what the client expects. This wrapper is quite simple:

{ "response": { "data" : ACTUAL_DATA } }

Thing is, I'm not a fan of explicitly wrapping each return value for all my request handlers. I also do not like having to unwrap these response wrappers in my unit tests.

Rather, I wonder if it were possible to return the ACTUAL_DATA as it were, and to intercept and wrap this data elsewhere.

If this is in fact possible, would it then be possible to read the annotations attached to the intercepted request handler? This way I can use custom annotations to decide how to wrap the data.

For example something like this would be amazing (note that @FetchResponse and @ResponseWrapper are made up proposed annotations):

@RequestMapping(...)
@FetchResponse
@ResponseBody
public List<User> getUsers() {
    ...
}

@ResponseWrapper(FetchResponse.class)
public Object wrap(Object value) {
    ResponseWrapper rw = new ResponseWrapper();
    rw.setData(value);
    return rw;
}

Anyone familiar with this territory? Or alternatively, and reasons why this might be bad practice?

Answer 1

Well, looks like I'm looking for Spring's "ResponseBodyAdvice" and "AbstractMappingJacksonResponseBodyAdvice".