Java电商项目面试--订单模块-蒲公英云

转自： https://blog.csdn.net/weixin_41835916/article/details/82017440

版权声明：小刺猬喜歡獨角獸 https://blog.csdn.net/weixin\_41835916/article/details/82017440
面试：订单模块技术要点
技术要点：
1、安全漏洞解决方案
2、订单号生成规则
3、强大的常量、枚举设计

一、前台创建订单
Controller层：

//创建订单
@RequestMapping(“create.do”)
@ResponseBody
public ServerResponse create(HttpSession session, Integer shippingId){
User user = (User)session.getAttribute(Const.CURRENT_USER);
if(user ==null)
return ServerResponse.createByErrorCodeMessage(ResponseCode.NEED_LOGIN.getCode(),ResponseCode.NEED_LOGIN.getDesc());
return iOrderService.createOrder(user.getId(),shippingId);
}

Service层：

//创建订单
public ServerResponse createOrder(Integer userId,Integer shippingId){
//从购物车中获取已经被勾选的商品
List cartList = cartMapper.selectCheckedCartByUserId(userId);
//校验并封装一下
ServerResponse serverResponse = this.getCartOrderItem(userId,cartList);
if(!serverResponse.isSuccess())
return serverResponse;
List orderItemList = (List)serverResponse.getData();
//计算这个订单的总价
BigDecimal payment = this.getOrderTotalPrice(orderItemList);
//生成订单
Order order = this.assembleOrder(userId,shippingId,payment);
if(order == null)
return ServerResponse.createByErrorMessage(“生成订单错误”);
if(CollectionUtils.isEmpty(orderItemList))
return ServerResponse.createByErrorMessage(“购物车为空”);
//每一项都生成订单号
for(OrderItem orderItem : orderItemList)
//设置订单号
orderItem.setOrderNo(order.getOrderNo());

//mybatis 批量插入  
orderItemMapper.batchInsert(orderItemList);  
//生成成功,我们要减少我们产品的库存  
this.reduceProductStock(orderItemList);  
//清空一下购物车  
this.cleanCart(cartList);  
//返回给前端数据  
OrderVo orderVo = assembleOrderVo(order,orderItemList);  
return ServerResponse.createBySuccess(orderVo);

}
//校验并且封装一下
private ServerResponse getCartOrderItem(Integer userId,List cartList){
List orderItemList = Lists.newArrayList();
//购物车中已经勾选的商品是空的
if(CollectionUtils.isEmpty(cartList))
return ServerResponse.createByErrorMessage(“购物车为空”);
/*********校验购物车的数据,包括产品的状态和数量********/
for(Cart cartItem : cartList){
OrderItem orderItem = new OrderItem();
//查出商品
Product product = productMapper.selectByPrimaryKey(cartItem.getProductId());
//查看产品销售状态
if(Const.ProductStatusEnum.ON_SALE.getCode() != product.getStatus()){
return ServerResponse.createByErrorMessage(“产品”+product.getName()+”不是在线售卖状态”);
}
//校验库存
if(cartItem.getQuantity() > product.getStock()){
return ServerResponse.createByErrorMessage(“产品”+product.getName()+”库存不足”);
}
/**********将已经勾选的购物车中的商品组装一下***********/
orderItem.setUserId(userId);
orderItem.setProductId(product.getId());
orderItem.setProductName(product.getName());
orderItem.setProductImage(product.getMainImage());
orderItem.setCurrentUnitPrice(product.getPrice());
orderItem.setQuantity(cartItem.getQuantity());
//此项商品的总价
orderItem.setTotalPrice(BigDecimalUtil.mul(product.getPrice().doubleValue(),cartItem.getQuantity()));
orderItemList.add(orderItem);
}
return ServerResponse.createBySuccess(orderItemList);
}
//此函数用于计算订单总价
private BigDecimal getOrderTotalPrice(List orderItemList){
BigDecimal payment = new BigDecimal(“0”);
for(OrderItem orderItem : orderItemList)
payment = BigDecimalUtil.add(payment.doubleValue(),orderItem.getTotalPrice().doubleValue()); //每一项的总价都加进来
return payment;
}
//此函数用于生成订单号
private long generateOrderNo(){
long currentTime = System.currentTimeMillis();
return currentTime + new Random().nextInt(100);
}
//此函数用于生成订单
private Order assembleOrder(Integer userId,Integer shippingId,BigDecimal payment){
Order order = new Order();
//生成订单号
long orderNo = this.generateOrderNo();
order.setOrderNo(orderNo);
//支付状态，未付款
order.setStatus(Const.OrderStatusEnum.NO_PAY.getCode());
order.setPostage(0); //运费设置为0
//支付方式，在线支付
order.setPaymentType(Const.PaymentTypeEnum.ONLINE_PAY.getCode());
order.setPayment(payment);

order.setUserId(userId);    //购买的用户的ID  
order.setShippingId(shippingId);   //发货地址的ID  
//发货时间等等  
//付款时间等等  
//插入订单  
int rowCount = orderMapper.insert(order);  
if(rowCount > 0)  
    return order;  
return null;

}
//减少商品的库存
private void reduceProductStock(List orderItemList){
for(OrderItem orderItem : orderItemList){
Product product = productMapper.selectByPrimaryKey(orderItem.getProductId());
product.setStock(product.getStock()-orderItem.getQuantity());
productMapper.updateByPrimaryKeySelective(product);
}
}
//清空购物车
private void cleanCart(List cartList){
for(Cart cart : cartList)
cartMapper.deleteByPrimaryKey(cart.getId());
}
//将订单包装一下
private OrderVo assembleOrderVo(Order order,List orderItemList){ //order:订单,orderItemList:订单明细
OrderVo orderVo = new OrderVo();
orderVo.setOrderNo(order.getOrderNo());
orderVo.setPayment(order.getPayment());
orderVo.setPaymentType(order.getPaymentType());
orderVo.setPaymentTypeDesc(Const.PaymentTypeEnum.codeOf(order.getPaymentType()).getValue());
orderVo.setPostage(order.getPostage());
orderVo.setStatus(order.getStatus());
orderVo.setStatusDesc(Const.OrderStatusEnum.codeOf(order.getStatus()).getValue());

orderVo.setShippingId(order.getShippingId());  
Shipping shipping = shippingMapper.selectByPrimaryKey(order.getShippingId());  
if(shipping != null)\{  
    orderVo.setReceiverName(shipping.getReceiverName());  
    orderVo.setShippingVo(assembleShippingVo(shipping));  
\}
orderVo.setPaymentTime(DateTimeUtil.dateToStr(order.getPaymentTime()));  
orderVo.setSendTime(DateTimeUtil.dateToStr(order.getSendTime()));  
orderVo.setEndTime(DateTimeUtil.dateToStr(order.getEndTime()));  
orderVo.setCreateTime(DateTimeUtil.dateToStr(order.getCreateTime()));  
orderVo.setCloseTime(DateTimeUtil.dateToStr(order.getCloseTime()));  
orderVo.setImageHost(PropertiesUtil.getProperty("ftp.server.http.prefix"));
List<OrderItemVo> orderItemVoList = Lists.newArrayList();
for(OrderItem orderItem : orderItemList)\{  
    OrderItemVo orderItemVo = assembleOrderItemVo(orderItem);  
    orderItemVoList.add(orderItemVo);  
\}  
orderVo.setOrderItemVoList(orderItemVoList);   //订单的明细  
return orderVo;

}
//封装收货地址
private ShippingVo assembleShippingVo(Shipping shipping){
ShippingVo shippingVo = new ShippingVo();
shippingVo.setReceiverName(shipping.getReceiverName());
shippingVo.setReceiverAddress(shipping.getReceiverAddress());
shippingVo.setReceiverProvince(shipping.getReceiverProvince());
shippingVo.setReceiverCity(shipping.getReceiverCity());
shippingVo.setReceiverDistrict(shipping.getReceiverDistrict());
shippingVo.setReceiverMobile(shipping.getReceiverMobile());
shippingVo.setReceiverZip(shipping.getReceiverZip());
shippingVo.setReceiverPhone(shippingVo.getReceiverPhone());
return shippingVo;
}

Mapper.xml：

insert into mmall_order_item (id, order_no,user_id, product_id,
product_name, product_image, current_unit_price,
quantity, total_price, create_time,
update_time)
values

(
#{item.id},#{item.orderNo},#{item.userId},#{item.productId},#{item.productName},#{item.productImage},#{item.currentUnitPrice},#{item.quantity},#{item.totalPrice},now(),now()
)

强大的常量、枚举设计
用接口定义常量最大的好处是有一个group的概念，很简单，我们相关的常量放在一个interface里，以后维护的成本会低很多。例如课程里的一些具有组概念的，就放在一个interface里，而相对独立的常量就用类常量。
枚举的话，key-value，有状态码，还有对应的中文说明，例如我们的订单状态。

public class Const {
public enum OrderStatusEnum{
CANCELED(0,”已取消”),
NO_PAY(10,”未支付”),
PAID(20,”已付款”),
SHIPPED(40,”已发货”),
ORDER_SUCCESS(50,”订单完成”),
ORDER_CLOSE(60,”订单关闭”);

    OrderStatusEnum(int code,String value)\{  
        this.code = code;  
        this.value = value;  
    \}  
    private String value;  
    private int code;
    public String getValue() \{  
        return value;  
    \}
    public int getCode() \{  
        return code;  
    \}
    public static OrderStatusEnum codeOf(int code)\{  
        for(OrderStatusEnum orderStatusEnum : values())\{  
            if(orderStatusEnum.getCode() == code)\{  
                return orderStatusEnum;  
            \}  
        \}  
        throw new RuntimeException("么有找到对应的枚举");  
    \}  
\}