个人名片：

博主：酒徒ᝰ.
专栏：瑞吉外卖
个人简介：沉醉在酒中，借着一股酒劲，去拼搏一个未来。
本篇励志：一份耕耘，一份收获。眼要看远，脚要近迈。在强者的眼中，没有最好，只有更好。向竞争挑战，向压力挑战，更要向自己挑战时间就是一切。

本项目基于B站黑马程序员Java项目实战《瑞吉外卖》，轻松掌握springboot + mybatis plus开发核心技术的真java实战项目。

视频链接【黑马程序员Java项目实战《瑞吉外卖》，轻松掌握springboot + mybatis
plus开发核心技术的真java实战项目】 https://www.bilibili.com/video/BV13a411q753?
点击观看

1.显示购物车

在手机端显示中已经完成。、

2.加入购物车

分析：shoppingCart地址，POST方式，add地址

/**
 * 添加菜品或套餐
 * @param shoppingCart
 * @param session
 * @return
 */
@PostMapping("/add")
public R<ShoppingCart> add(@RequestBody ShoppingCart shoppingCart, HttpSession session){
    //log.info("shoppingCart:{}", shoppingCart);//shoppingCart:ShoppingCart(id=null, name=邵阳猪血丸子, image=2a50628e-7758-4c51-9fbb-d37c61cdacad.jpg, userId=null, dishId=1397851370462687234, setmealId=null, dishFlavor=多冰,不要葱,不辣, number=null, amount=138, createTime=null)
    //设置用户id
    shoppingCart.setUserId((Long) session.getAttribute("user"));
    //设置该购物车创建时间
    shoppingCart.setCreateTime(LocalDateTime.now());

    //需要判断菜品或套餐是否在购物车里
    //1.区分添加的是菜品还是套餐
    LambdaQueryWrapper<ShoppingCart> queryWrapper = new LambdaQueryWrapper<>();
    Long dishId = shoppingCart.getDishId();
    if (dishId != null){
        //菜品
        queryWrapper.eq(ShoppingCart::getDishId, dishId);
    }else {
        //套餐
        queryWrapper.eq(ShoppingCart::getSetmealId, shoppingCart.getSetmealId());
    }
    //2.查看购物车内该菜品或套餐是否为空
    ShoppingCart shopping = shoppingCartService.getOne(queryWrapper);
    if (shopping == null){
        shoppingCart.setNumber(1);
        shoppingCartService.save(shoppingCart);
        shopping = shoppingCart;
    }else {
        shopping.setNumber(shopping.getNumber() + 1);
        shoppingCartService.updateById(shopping);
    }

    return R.success(shopping);
}

3.清空购物车

分析：shoppingCart地址，DELETE方式，clean地址

/**
 * 清空购物车
 * @param session
 * @return
 */
@DeleteMapping("/clean")
public R<String> clean(HttpSession session){
    //根据用户id清空购物车
    LambdaQueryWrapper<ShoppingCart> queryWrapper = new LambdaQueryWrapper<>();
    queryWrapper.eq(ShoppingCart::getUserId, (Long)session.getAttribute("user"));
    shoppingCartService.remove(queryWrapper);
    return R.success("清空购物车成功");
}

4.购物车内减少菜品或套餐

分析：shoppingCart地址，POST方式，sub地址
这里与添加菜品与套餐类似，直接复制过来进行简单修改即可。注意购物车内菜品或套餐数量一旦为0，直接删除该菜品或套餐。

/**
 * 减少菜品或套餐
 * @param shoppingCart
 * @param session
 * @return
 */
@PostMapping("/sub")
public R<ShoppingCart> sub(@RequestBody ShoppingCart shoppingCart, HttpSession session){
    //log.info("shoppingCart:{}", shoppingCart);//shoppingCart:ShoppingCart(id=null, name=邵阳猪血丸子, image=2a50628e-7758-4c51-9fbb-d37c61cdacad.jpg, userId=null, dishId=1397851370462687234, setmealId=null, dishFlavor=多冰,不要葱,不辣, number=null, amount=138, createTime=null)

    //需要判断菜品或套餐是否在购物车里
    //1.区分减少的是菜品还是套餐
    LambdaQueryWrapper<ShoppingCart> queryWrapper = new LambdaQueryWrapper<>();
    Long dishId = shoppingCart.getDishId();
    if (dishId != null){
        //菜品
        queryWrapper.eq(ShoppingCart::getDishId, dishId);
    }else {
        //套餐
        queryWrapper.eq(ShoppingCart::getSetmealId, shoppingCart.getSetmealId());
    }
    //2.查看购物车内该菜品或套餐数量是否大于等于1
    ShoppingCart shopping = shoppingCartService.getOne(queryWrapper);
    if (shopping.getNumber() > 1){
        shopping.setNumber(shopping.getNumber() - 1);
        shoppingCartService.updateById(shopping);
    }else if (shopping.getNumber() == 1){
        shopping.setNumber(shopping.getNumber() - 1);
        shoppingCartService.removeById(shopping);
    }

    return R.success(shopping);
}