public IActionResult GetBookChapterById(Guid id)
        {
            BookChapter chapter = _bookChaptersService.Find(id);

            if (chapter == null)
            {
                return(NotFound());
            }
            else
            {
                return(new ObjectResult(chapter));
            }
        }
        public IActionResult GetBookChapterById(Guid id)
        {
            BookChapter chapter = _bookChaptersService.Find(id);

            if (chapter == null)
            {
                // NotFound返回404(未找到)响应
                return(NotFound());
            }
            else
            {
                // ObjectResult返回状态代码200,其中包含正文中的书籍章节
                return(new ObjectResult(chapter));
            }
        }