学习目标：

开发订单模块

了解希尔排序的基本原理

学习内容：

完成了创建订单的接口的开发与测试。

package com.imooc.mall.Service.impl;

import com.imooc.mall.Service.CartService;
import com.imooc.mall.Service.OrderService;
import com.imooc.mall.common.Constant;
import com.imooc.mall.exception.ImoocMallException;
import com.imooc.mall.exception.ImoocMallExceptionEnum;
import com.imooc.mall.filter.UserFilter;
import com.imooc.mall.model.dao.CartMapper;
import com.imooc.mall.model.dao.OrderItemMapper;
import com.imooc.mall.model.dao.OrderMapper;
import com.imooc.mall.model.dao.ProductMapper;
import com.imooc.mall.model.pojo.Order;
import com.imooc.mall.model.pojo.OrderItem;
import com.imooc.mall.model.pojo.Product;
import com.imooc.mall.model.request.CreateOrderReq;
import com.imooc.mall.model.vo.CartVO;
import com.imooc.mall.util.OrderCodeFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.util.CollectionUtils;

import java.util.ArrayList;
import java.util.List;

/**
 * 描述：  订单Service实现类
 */
@Service
public class OrderServiceImpl implements OrderService {
    @Autowired
    CartService cartService;
    @Autowired
    ProductMapper productMapper;
    @Autowired
    CartMapper cartMapper;
    @Autowired
    OrderMapper orderMapper;
    @Autowired
    OrderItemMapper orderItemMapper;
    @Override
    public String create(CreateOrderReq createOrderReq) {
        //拿到用户ID
        Integer userId = UserFilter.currentUser.getId();
        //从购物车查找已经勾选的商品
        List<CartVO> cartVOList = cartService.list(userId);
        ArrayList<CartVO> cartVOListTemp = new ArrayList<>();
        for (int i = 0; i < cartVOList.size(); i++) {
            CartVO cartVO = cartVOList.get(i);
            if (cartVO.getSelected().equals(Constant.Cart.CHECKED)) {
                cartVOListTemp.add(cartVO);
            }
        }
        cartVOList = cartVOListTemp;
        //如果购物车已勾选的为空，报错
        if (CollectionUtils.isEmpty(cartVOList)) {
            throw new ImoocMallException(ImoocMallExceptionEnum.CART_EMPTY);
        }
        //判断商品是否存在，上下架状态、库存
        validSaleStatusAndStock(cartVOList);
        //把购物车对象转化为订单item对象
        List<OrderItem> orderItemList = cartVOListToOrderItemList(cartVOList);
        //扣库存
        for (int i = 0; i < orderItemList.size(); i++) {
            OrderItem orderItem = orderItemList.get(i);
            Product product = productMapper.selectByPrimaryKey(orderItem.getProductId());
            int stock = product.getStock() - orderItem.getQuantity();
            if (stock < 0) {
                throw new ImoocMallException(ImoocMallExceptionEnum.NOT_ENOUGH);
            }
            product.setStock(stock);
            productMapper.updateByPrimaryKeySelective(product);
        }
        //把购物车中已勾选的商品删除
        cleanCart(cartVOList);
        //生成订单
        Order order = new Order();
        //生成订单号，有独立的规则
        String orderNo = OrderCodeFactory.getOrderCode(Long.valueOf(userId));
        order.setOrderNo(orderNo);
        order.setUserId(userId);
        order.setTotalPrice(totalPrice(orderItemList));
        order.setReceiverName(createOrderReq.getReceiverName());
        order.setReceiverMobile(createOrderReq.getReceiverMobile());
        order.setReceiverAddress(createOrderReq.getReceiverAddress());
        order.setOrderStatus(Constant.OrderStatusEnum.NOT_PAIY.getCode());
        order.setPostage(0);
        order.setPaymentType(1);
        //插入到Order表
        orderMapper.insertSelective(order);
        //循环保存每个商品到order_item表
        for (int i = 0; i < orderItemList.size(); i++) {
            OrderItem orderItem = orderItemList.get(i);
            order.setOrderNo(order.getOrderNo());
            orderItemMapper.insertSelective(orderItem);
        }
        //把结果返回
        return orderNo;
    }

    private Integer totalPrice(List<OrderItem> orderItemList) {
        Integer totalPrice = 0;
        for (int i = 0; i < orderItemList.size(); i++) {
            OrderItem orderItem = orderItemList.get(i);
            totalPrice+=orderItem.getTotalPrice();
        }
        return totalPrice;
    }

    private void cleanCart(List<CartVO> cartVOList) {
        for (int i = 0; i < cartVOList.size(); i++) {
            CartVO cartVO = cartVOList.get(i);
            cartMapper.deleteByPrimaryKey(cartVO.getId());
        }
    }

    private List<OrderItem> cartVOListToOrderItemList(List<CartVO> cartVOList) {
        List<OrderItem> orderItemList = new ArrayList<>();
        for (int i = 0; i < cartVOList.size(); i++) {
            CartVO cartVO = cartVOList.get(i);
            OrderItem orderItem = new OrderItem();
            orderItem.setProductId(cartVO.getProductId());
            //记录商品快照信息
            orderItem.setProductName(cartVO.getProductName());
            orderItem.setProductImg(cartVO.getProductImage());
            orderItem.setUnitPrice(cartVO.getPrice());
            orderItem.setQuantity(cartVO.getQuantity());
            orderItem.setTotalPrice(cartVO.getTotalPrice());
            orderItemList.add(orderItem);
        }
        return orderItemList;
    }

    private void validSaleStatusAndStock(List<CartVO> cartVOList) {
        for (int i = 0; i < cartVOList.size(); i++) {
            CartVO cartVO = cartVOList.get(i);
            Product product = productMapper.selectByPrimaryKey(cartVO.getProductId());
            //判断商品是否存在，是否上架
            if (product == null || product.getStatus().equals(Constant.SaleStatus.NOT_SALE)) {
                throw new ImoocMallException(ImoocMallExceptionEnum.NOT_SALE);
            }
            //判断商品库存
            if (cartVO.getQuantity() > product.getStock()) {
                throw new ImoocMallException(ImoocMallExceptionEnum.NOT_ENOUGH);
            }
        }
    }
}

学习时间：

08：20-11：10    15：00 -17：00 18：00 -20：00

学习产出：

对于添加订单这一个复杂的业务逻辑进行了实现，其中包括数据库的多表关联查询，对象的转换与扣库存，还有状态枚举等。