小程序添加购物车业务逻辑

数据库设计

DTO设计

实现步骤

1 判断当前加入购物车中的的商品是否已经存在了

2 如果已经存在 只需要将数量加一

3 如果不存在 插入一条购物车数据

4 判断加到本次购物车的是菜品还是套餐

Impl代码实现

@Service
public class ShoppingCartServiceImpl implements ShoppingCartService {

    @Autowired
    private ShoppingCartMapper shoppingCartMapper;
    @Autowired
    private DishMapper dishMapper;
    @Autowired
    private SetmealMapper setmealMapper;
    /**
     * 添加购物车
     * @param shoppingCartDTO
     */
    @Override
    public void add(ShoppingCartDTO shoppingCartDTO) {

        //判断当前加入购物车中的的商品是否已经存在了
        ShoppingCart shoppingCart = new ShoppingCart();
        BeanUtils.copyProperties(shoppingCartDTO,shoppingCart);
        shoppingCart.setUserId(BaseContext.getCurrentId());
        List<ShoppingCart> list = shoppingCartMapper.list(shoppingCart);
        //如果已经存在 只需要将数量加一
        if (list!=null&&list.size()>0){
            ShoppingCart cart = list.get(0);
            cart.setNumber(cart.getNumber()+1);
            shoppingCartMapper.updateNumberById(cart);
        }else{
            //如果不存在 插入一条购物车数据
            //判断加到本次购物车的是菜品还是套餐
           Long dishId = shoppingCartDTO.getDishId();
           if (dishId!=null){
               //添加到购物车的是菜品
              Dish dish = dishMapper.getById(dishId);
              shoppingCart.setName(dish.getName());
              shoppingCart.setImage(dish.getImage());
              shoppingCart.setAmount(dish.getPrice());

           }else{
               //添加到购物车的是套餐
               Long setmealId = shoppingCartDTO.getSetmealId();

               Setmeal setmeal = setmealMapper.getById(setmealId);
               shoppingCart.setName(setmeal.getName());
               shoppingCart.setImage(setmeal.getImage());
               shoppingCart.setAmount(setmeal.getPrice());

           }
            shoppingCart.setNumber(1);
            shoppingCart.setCreateTime(LocalDateTime.now());
            shoppingCartMapper.insert(shoppingCart);
        }
    }

    @Override
    public List<ShoppingCart> showShoppingCart() {
        Long userId = BaseContext.getCurrentId();
        ShoppingCart shoppingCart = ShoppingCart.builder().userId(userId).build();
        List<ShoppingCart> list = shoppingCartMapper.list(shoppingCart);
        return list;
    }

    @Override
    public void clean() {
        shoppingCartMapper.deleteByUserId(BaseContext.getCurrentId());
    }
}