[Spring] ResponseEntity 형으로 Return 하기 (Json)

// produces = MediaType.APPLICATION_JSON_VALUE
// RequestMapping "/error-page/500 동일한게 있지만 위에 조건이 있으면 Header에 ACCEPT가 application/json인 경우에는
// 아래 RequestMapping이 실행이된다.
@RequestMapping(value="/error-page/500", produces = MediaType.APPLICATION_JSON_VALUE)
    public ResponseEntity<Map<String, Object>> errorpage500Api(
            HttpServletRequest request, HttpServletResponse response) {
        log.info("API errorPage 500");

        Map<String, Object> result = new HashMap<>();
        Exception ex = (Exception) request.getAttribute(ERROR_EXCEPTION);
        result.put("status", request.getAttribute(ERROR_EXCEPTION));
        result.put("message", ex.getMessage());

        Integer statusCode = (Integer) request.getAttribute(RequestDispatcher.ERROR_STATUS_CODE);
        return new ResponseEntity<>(result, HttpStatus.valueOf(statusCode));
    } 

ResponseEntity설명 블로그 :
https://devlog-wjdrbs96.tistory.com/182