黑马程序员Java项目实战《瑞吉外卖》，轻松掌握springboot + ...

Day6老师跳过的，减少购物车商品数量的响应，为节省篇幅，我写在controller里：

  @PostMapping("/sub")

  public R<String> sub(@RequestBody SetmealDish setmealDish){

    Long userId=BaseContext.getCurrentId();

    LambdaQueryWrapper<ShoppingCart> queryWrapper = new LambdaQueryWrapper<>();

    if (setmealDish.getSetmealId() != null) {

      Long setmealId = setmealDish.getSetmealId();

      queryWrapper.eq(ShoppingCart::getSetmealId, setmealId).eq(ShoppingCart::getUserId, userId);

    } else {

      Long dishId = setmealDish.getDishId();

      queryWrapper.eq(ShoppingCart::getDishId, dishId).eq(ShoppingCart::getUserId, userId);

    }

    ShoppingCart shoppingCart = shoppingCartService.getOne(queryWrapper);

    if (shoppingCart != null) {

      if (shoppingCart.getNumber() == 1) {

        shoppingCartService.removeById(shoppingCart);

      } else {

        shoppingCart.setNumber(shoppingCart.getNumber() - 1);

        shoppingCartService.updateById(shoppingCart);

      }

      return R.success("成功");

    } else {

      return R.error("购物车中不存在该商品");

    }

  }