添加购物车业务代码

思路:

1.判断当前购物车商品是否存在了

2.判断本次添加的是菜品表还是套餐表

ShoppingCartControlle

@RestController
@RequestMapping("/user/shoppingCart")
@Slf4j
@Api(tags = "c段购物车接口")
public class ShoppingCartControlle {
    @Autowired
    private ShoppingCartService shoppingCartService;

    /**
     * 添加购物车
     *
     * @param shoppingCartDTO
     * @return
     */
    @PostMapping("/add")
    @ApiOperation("添加购物车")
    public Result add(@RequestBody ShoppingCartDTO shoppingCartDTO) {
        log.info("添加购物车，商品信息为：{}", shoppingCartDTO);
        shoppingCartService.addShoppingCart(shoppingCartDTO);

        return Result.success();
    }
}

ShoppingCartService

public interface ShoppingCartService {
    /**
     * 添加购物车方法
     * @param shoppingCartDTO
     */

    void addShoppingCart(ShoppingCartDTO shoppingCartDTO);
}

ShoppingCartServiceImpl

@Service
@Slf4j
public class ShoppingCartServiceImpl  implements ShoppingCartService {
    @Autowired
    private ShoppingCartMapper shoppingCartMapper;
    @Autowired
    private DishMapper dishMapper;
    @Autowired
    private SetmealMapper setmealMapper;

    /**
     * 添加购物车
     * @param shoppingCartDTO
     */
    public void addShoppingCart(ShoppingCartDTO shoppingCartDTO) {
        //判断当前购物车商品是否存在了
        ShoppingCart shoppingCart = new ShoppingCart();
        BeanUtils.copyProperties(shoppingCartDTO, shoppingCart);
        //获得用户ID
        Long userId = BaseContext.getCurrentId();
        //添加进去
        shoppingCart.setUserId(userId);
        List<ShoppingCart> list =
                shoppingCartMapper.list(shoppingCart);

        //如果存在，那么数量+1就行了
        if (list != null && list.size() > 0) {
            //list集合只会有一种数据

            ShoppingCart cart = list.get(0);
            cart.setNumber(cart.getNumber() + 1);
            shoppingCartMapper.updateUnmberById(cart);
        }else {
            //如果不存在，需要来插入一条购物车数据
            //判断本次添加的是菜品表还是套餐表
            Long dishId = shoppingCartDTO.getDishId();
            if (dishId != null) {
                //本次添加的是菜品表
                Dish dish = dishMapper.getById(dishId);
                shoppingCart.setName(dish.getName());
                shoppingCart.setImage(dish.getImage());
                shoppingCart.setAmount(dish.getPrice());
            }else {
                //本次添加的是套餐
                Long setmalId = shoppingCartDTO.getSetmealId();
                Setmeal setmeal = setmealMapper.getId(setmalId);
                shoppingCart.setName(setmeal.getName());
                shoppingCart.setImage(setmeal.getImage());
                shoppingCart.setAmount(setmeal.getPrice());
            }
            shoppingCart.setNumber( 1);
            shoppingCart.setCreateTime(LocalDateTime.now());
            shoppingCartMapper.insert(shoppingCart);

        }



    }
}

ShoppingCartMapper

@Mapper
public interface ShoppingCartMapper {
    /**
     * 动态条件查询
     * @param shoppingCart
     * @return
     */
    List<ShoppingCart> list(ShoppingCart shoppingCart);

    /**
     * 修改菜品数量
     * @param cart
     */
    @Update("update sky_take_out.shopping_cart set number=#{number} where id=#{id} ")
    void updateUnmberById(ShoppingCart cart);

    /**
     * 插入购物车数据
     * @param shoppingCart
     */
    @Insert("insert into sky_take_out.shopping_cart(name, user_id,  dish_id, setmeal_id, dish_flavor, number, amount, image,create_time)  values" +
            " (#{name},#{userId},#{dishId},#{setmealId},#{dishFlavor},#{number},#{amount},#{image},#{createTime})")
    void insert(ShoppingCart shoppingCart);
}

ShoppingCartMapper

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.sky.mapper.ShoppingCartMapper">

    <select id="list" resultType="com.sky.entity.ShoppingCart">
        select * from sky_take_out.shopping_cart
        <where>
            <if test="userId != null">
                and user_id = #{userId}
            </if>
            <if test="setmealId !=null">
                and setmeal_id =#{setmealId}
            </if>
            <if test="dishId !=null">
                and dish_id =#{dishId}
            </if>
            <if test="dishFlavor!=null">
                and dish_flavor =#{dishFlavor}
            </if>
        </where>
    </select>
</mapper>