用户下单

移动端用户将菜品或者套餐加入购物车后，可以点击购物车中的 【去结算】 按钮

页面跳转到订单确认页面，点击 【去支付】按钮则完成下单操作。

用户下单业务对应的数据表为orders表和order_detail表：
orders：订单表
order_detail：订单明细表

订单表的具体表结构如下：

订单明细表的具体表结构如下：

在开发代码之前，需要梳理一下用户下单操作时前端页面和服务端的交互过程：
1、在购物车中点击去结算按钮，页面跳转到订单确认页面
2、在订单确认页面，发送ajax请求，请求服务端获取当前登录用户的默认地址
3、在订单确认页面，发送ajax请求，请求服务端获取当前登录用户的购物车数据
4、在订单确认页面点击去支付按钮，发送ajax请求，请求服务端完成下单操作

开发用户下单功能，其实就是在服务端编写代码去处理前端页面发送的请求即可。

package com.po.reggie.service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.toolkit.IdWorker;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.po.reggie.common.BaseContext;
import com.po.reggie.common.CustomException;
import com.po.reggie.domain.*;
import com.po.reggie.mapper.OrderMapper;
import com.po.reggie.service.*;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.math.BigDecimal;
import java.time.LocalDateTime;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;

@Service
@Slf4j
public class OrderServiceImpl extends ServiceImpl<OrderMapper, Orders> implements OrderService {

    @Autowired
    private ShoppingCartService shoppingCartService;

    @Autowired
    private UserService userService;

    @Autowired
    private AddressBookService addressBookService;

    @Autowired
    private OrderDetailService orderDetailService;

    /**
     * 用户下单
     * @param orders
     */
    @Transactional
    public void submit(Orders orders) {
        //获得当前用户id
        Long userId = BaseContext.getCurrentId();

        //查询当前用户的购物车数据
        LambdaQueryWrapper<ShoppingCart> wrapper = new LambdaQueryWrapper<>();
        wrapper.eq(ShoppingCart::getUserId,userId);
        List<ShoppingCart> shoppingCarts = shoppingCartService.list(wrapper);

        if(shoppingCarts == null || shoppingCarts.size() == 0){
            throw new CustomException("购物车为空，不能下单");
        }

        //查询用户数据
        User user = userService.getById(userId);

        //查询地址数据
        Long addressBookId = orders.getAddressBookId();
        AddressBook addressBook = addressBookService.getById(addressBookId);
        if(addressBook == null){
            throw new CustomException("用户地址信息有误，不能下单");
        }

        long orderId = IdWorker.getId();//订单号

        AtomicInteger amount = new AtomicInteger(0);

        List<OrderDetail> orderDetails = shoppingCarts.stream().map((item) -> {
            OrderDetail orderDetail = new OrderDetail();
            orderDetail.setOrderId(orderId);
            orderDetail.setNumber(item.getNumber());
            orderDetail.setDishFlavor(item.getDishFlavor());
            orderDetail.setDishId(item.getDishId());
            orderDetail.setSetmealId(item.getSetmealId());
            orderDetail.setName(item.getName());
            orderDetail.setImage(item.getImage());
            orderDetail.setAmount(item.getAmount());
            amount.addAndGet(item.getAmount().multiply(new BigDecimal(item.getNumber())).intValue());
            return orderDetail;
        }).collect(Collectors.toList());


        orders.setId(orderId);
        orders.setOrderTime(LocalDateTime.now());
        orders.setCheckoutTime(LocalDateTime.now());
        orders.setStatus(2);
        orders.setAmount(new BigDecimal(amount.get()));//总金额
        orders.setUserId(userId);
        orders.setNumber(String.valueOf(orderId));
        orders.setUserName(user.getName());
        orders.setConsignee(addressBook.getConsignee());
        orders.setPhone(addressBook.getPhone());
        orders.setAddress((addressBook.getProvinceName() == null ? "" : addressBook.getProvinceName())
                + (addressBook.getCityName() == null ? "" : addressBook.getCityName())
                + (addressBook.getDistrictName() == null ? "" : addressBook.getDistrictName())
                + (addressBook.getDetail() == null ? "" : addressBook.getDetail()));
        //向订单表插入数据，一条数据
        this.save(orders);

        //向订单明细表插入数据，多条数据
        orderDetailService.saveBatch(orderDetails);

        //清空购物车数据
        shoppingCartService.remove(wrapper);
    }
}