public async Task <ActionResult <AcademyDto> > CreateAcademy([FromBody] AcademyAddDto academyAddDto)
        {
            //ApiController在遇到academyAddDto为空时可以自动返回400错误
            var academy = _mapper.Map <Academy>(academyAddDto);

            _academyRepository.AddAcademy(academy);//只是被添加到DbContext里
            await _academyRepository.SaveAsync();

            var academyDto = _mapper.Map <AcademyDto>(academy);

            return(CreatedAtRoute(nameof(GetAcademy), new { academyId = academy.AcademyId }, academyDto));
        }