Tùy chỉnh ngoại lệ không tìm thấy tài nguyên khi duyệt web

BookController.java

@Controller
public class BookController {

	private static final Logger logger = LoggerFactory.getLogger(BookController.class);

	@Autowired
	@Qualifier("bookService")
	private BookService bookService;

	@Autowired
	@Qualifier("cartBean")
	private Cart cartBean;

	@ExceptionHandler(ResourceNotFoundException.class)
	public String handleResourceNotFoundException(HttpServletRequest request) {
		HttpSession session = request.getSession(true);
		session.setAttribute("cartBean", cartBean);
		return "404page";
	}

	@RequestMapping(value = "/book/detail/{bookId}")
	@SuppressWarnings("unchecked")
	public String details(@PathVariable("bookId") long bookId, Model model, HttpServletRequest request) {
		logger.info("Show Book Detail Page");
		HttpSession session = request.getSession(false);
		Book book = null;
		if (session != null && session.getAttribute("books") != null) {
			List<Book> books = (List<Book>) session.getAttribute("books");
			for (Book b : books) {
				if (b.getId() == bookId) {
					book = b;
					model.addAttribute("book", b);
					break;
				}
			}
			if (book == null) {
				throw new ResourceNotFoundException();
			}
		} else {
			book = bookService.findBook(bookId);
			if (book == null) {
				throw new ResourceNotFoundException();
			}
			model.addAttribute("book", book);
		}
		return "book-detail";
	}
}

ResourceNotFoundController.java

@Controller
@SessionAttributes(names = "cartBean")
public class ResourceNotFoundController {

@Controller
@SessionAttributes(names = "cartBean")
public class ResourceNotFoundController {

	@Autowired
	@Qualifier("cartBean")
	private Cart cartBean;

	@RequestMapping("/404")
	public String handleResourceNotFound(Model model, HttpServletRequest request) {
		HttpSession session = request.getSession(false);
		if (session == null) {
			model.addAttribute("cartBean", cartBean);
		}
		return "404page";
	}
}

ResourceNotFoundException.java

@ResponseStatus(HttpStatus.NOT_FOUND)
public class ResourceNotFoundException extends RuntimeException {
	private static final long serialVersionUID = -3329819391367130855L;
}