Java springmvc三层体系结构中的异常处理

我正在构建一个具有3层的简单web应用程序—DAO、服务、MVC。当我在控制器中时，我想删除菜单组，它包含我获得ConstraintViolationException的菜单

我应该在哪里处理此异常？在DAO、服务或控制器中？目前我正在控制器中处理异常

下面是我的代码

DAO删除菜单组的方法：

@Override
public void delete(E e){
    if (e == null){
        throw new DaoException("Entity can't be null.");
    }

    getCurrentSession().delete(e);
}

@Override
@Transactional(readOnly = false)
public void delete(MenuGroupEntity menuGroupEntity) {
    menuGroupDao.delete(menuGroupEntity);
}

@RequestMapping(value = "/{menuGroupId}/delete", method = RequestMethod.GET)
public ModelAndView delete(@PathVariable Long menuGroupId, RedirectAttributes redirectAttributes){
    MenuGroupEntity menuGroupEntity = menuGroupService.find(menuGroupId);

    if (menuGroupEntity != null){
        try {
            menuGroupService.delete(menuGroupEntity);
            redirectAttributes.addFlashAttribute("flashMessage", "admin.menu-group-deleted");
            redirectAttributes.addFlashAttribute("flashMessageType", "success");
        } catch (Exception e){
            redirectAttributes.addFlashAttribute("flashMessage", "admin.menu-group-could-not-be-deleted");
            redirectAttributes.addFlashAttribute("flashMessageType", "danger");
        }
    }

    return new ModelAndView("redirect:/admin/menu-group");
}

删除菜单组的服务方法：

@Override
public void delete(E e){
    if (e == null){
        throw new DaoException("Entity can't be null.");
    }

    getCurrentSession().delete(e);
}

@Override
@Transactional(readOnly = false)
public void delete(MenuGroupEntity menuGroupEntity) {
    menuGroupDao.delete(menuGroupEntity);
}

@RequestMapping(value = "/{menuGroupId}/delete", method = RequestMethod.GET)
public ModelAndView delete(@PathVariable Long menuGroupId, RedirectAttributes redirectAttributes){
    MenuGroupEntity menuGroupEntity = menuGroupService.find(menuGroupId);

    if (menuGroupEntity != null){
        try {
            menuGroupService.delete(menuGroupEntity);
            redirectAttributes.addFlashAttribute("flashMessage", "admin.menu-group-deleted");
            redirectAttributes.addFlashAttribute("flashMessageType", "success");
        } catch (Exception e){
            redirectAttributes.addFlashAttribute("flashMessage", "admin.menu-group-could-not-be-deleted");
            redirectAttributes.addFlashAttribute("flashMessageType", "danger");
        }
    }

    return new ModelAndView("redirect:/admin/menu-group");
}

删除控制器中菜单组的控制器方法：

@Override
public void delete(E e){
    if (e == null){
        throw new DaoException("Entity can't be null.");
    }

    getCurrentSession().delete(e);
}

@Override
@Transactional(readOnly = false)
public void delete(MenuGroupEntity menuGroupEntity) {
    menuGroupDao.delete(menuGroupEntity);
}

@RequestMapping(value = "/{menuGroupId}/delete", method = RequestMethod.GET)
public ModelAndView delete(@PathVariable Long menuGroupId, RedirectAttributes redirectAttributes){
    MenuGroupEntity menuGroupEntity = menuGroupService.find(menuGroupId);

    if (menuGroupEntity != null){
        try {
            menuGroupService.delete(menuGroupEntity);
            redirectAttributes.addFlashAttribute("flashMessage", "admin.menu-group-deleted");
            redirectAttributes.addFlashAttribute("flashMessageType", "success");
        } catch (Exception e){
            redirectAttributes.addFlashAttribute("flashMessage", "admin.menu-group-could-not-be-deleted");
            redirectAttributes.addFlashAttribute("flashMessageType", "danger");
        }
    }

    return new ModelAndView("redirect:/admin/menu-group");
}

---

除非需要，否则您应该仅在服务层中处理异常，作为设计的一部分。考虑一个需求，在这个需求中，您还需要为某些其他映射使用相同的功能

deletemu

从任何设计角度来看。让控制器非常具体地处理模型属性，只为映射到业务逻辑的请求提供服务。在服务层中保留一个方法，以便在抛出参数或发生DB错误时获取

menuGroupId

，并从该服务中抛出异常

详情请参阅：