@RequestMapping(value = "/sach/add", method = RequestMethod.POST)
  public String create(SachUI sachUI, Model model) {
    TheLoaiSach theLoaiSach = theLoaiSachService.timTheLoaiSachByTen(sachUI.getTheLoaiUI());
    if (theLoaiSach != null) {
      Sach sach = SachMapper.convertToSach(sachUI, theLoaiSach);
      sachService.saveOrUpdate(sach);
    }

    return "redirect:/sach/list";
  }
 @RequestMapping(value = "/sach/edit", method = RequestMethod.GET)
 public String hienThiSuaSach(
     @RequestParam(value = "maSach", required = true) String maSach, Model model) {
   Sach sachExisting = sachService.timSachByMaSach(maSach);
   if (sachExisting != null) {
     SachUI sachUI = SachMapper.convertToSachUI(sachExisting);
     model.addAttribute("sachUI", sachUI);
     List<TheLoaiSach> tLSs = theLoaiSachService.timDanhMucTheLoaiSach();
     List<TheLoaiSachUI> tLSUIs = TheLoaiSachMapper.convertToListTheLoaiSachUI(tLSs);
     model.addAttribute("theLoaiUIs", tLSUIs);
   }
   model.addAttribute("btnName", "Sửa Thông Tin Sách");
   return WebConstant.views.THEM_SACH;
 }
 @RequestMapping(value = "/sach/add", method = RequestMethod.GET)
 public String hienThiThemSach(Model model) {
   List<TheLoaiSach> theLoaiSachs = theLoaiSachService.timDanhMucTheLoaiSach();
   List<TheLoaiSachUI> theLoaiSachUIs = new ArrayList<TheLoaiSachUI>();
   if (theLoaiSachs.size() > 0) {
     for (TheLoaiSach theLoaiSach : theLoaiSachs) {
       TheLoaiSachUI tLSachUIL = new TheLoaiSachUI();
       tLSachUIL.setMaTheLoai(theLoaiSach.getMaTheLoai());
       tLSachUIL.setTenTheLoai(theLoaiSach.getTenTheLoai());
       theLoaiSachUIs.add(tLSachUIL);
     }
   }
   SachUI sachUI = new SachUI();
   sachUI.setMaSach(UUID.randomUUID().toString());
   model.addAttribute("theLoaiUIs", theLoaiSachUIs);
   model.addAttribute("sachUI", sachUI);
   model.addAttribute("btnName", "Thêm Sách Mới");
   return WebConstant.views.THEM_SACH;
 }