V2EX › chwangtenger 的所有回复 › 第 1 页 / 共 1 页

@limuyan44 代码有好几层，那我贴一下

MiaoshaController.java

@RequestMapping(value="/do_miaosha", method= RequestMethod.POST)
@ResponseBody
public Result<OrderInfo> miaosha(Model model,MiaoshaUser user,
@RequestParam("goodsId")long goodsId) {
model.addAttribute("user", user);
if(user == null) {
return Result.error(CodeMsg.SESSION_ERROR);
}
//判断库存
GoodsVo goods = goodsService.getGoodsVoByGoodsId(goodsId);//10 个商品，req1 req2
int stock = goods.getStockCount();
if(stock <= 0) {
return Result.error(CodeMsg.MIAO_SHA_OVER);
}
//判断是否已经秒杀到了
MiaoshaOrder order = orderService.getMiaoshaOrderByUserIdGoodsId(user.getId(), goodsId);
if(order != null) {
return Result.error(CodeMsg.REPEATE_MIAOSHA);
}
//减库存下订单写入秒杀订单
OrderInfo orderInfo = miaoshaService.miaosha(user, goods); //我提问的操作在这个函数里面
return Result.success(orderInfo);
}

MiaoshaService.java 中，上文的 miaoshaService.miaosha

@Transactional
public OrderInfo miaosha(MiaoshaUser user, GoodsVo goods) {
//减库存下订单写入秒杀订单
goodsService.reduceStock(goods);
//order_info maiosha_order
return orderService.createOrder(user, goods);
}

GoodsService.java 中，上文的 goodsService.reduceStock

public void reduceStock(GoodsVo goods) {
MiaoshaGoods g = new MiaoshaGoods();
g.setGoodsId(goods.getId());
goodsDao.reduceStock(g);
}

GoodsDao.java 中，上文的 goodsDao.reduceStock
@Update("update miaosha_goods set stock_count = stock_count - 1 where goods_id = #{goodsId} and stock_count > 0")
public int reduceStock(MiaoshaGoods g);

OrderService 上上上段代码最后一句，中的 orderService.createOrder

@Transactional
public OrderInfo createOrder(MiaoshaUser user, GoodsVo goods) {
OrderInfo orderInfo = new OrderInfo();
orderInfo.setCreateDate(new Date());
orderInfo.setDeliveryAddrId(0L);
orderInfo.setGoodsCount(1);
orderInfo.setGoodsId(goods.getId());
orderInfo.setGoodsName(goods.getGoodsName());
orderInfo.setGoodsPrice(goods.getMiaoshaPrice());
orderInfo.setOrderChannel(1);
orderInfo.setStatus(0);
orderInfo.setUserId(user.getId());
long orderId = orderDao.insert(orderInfo);

System.out.println();
MiaoshaOrder miaoshaOrder = new MiaoshaOrder();
miaoshaOrder.setGoodsId(goods.getId());
miaoshaOrder.setOrderId(orderId);
miaoshaOrder.setUserId(user.getId());
orderDao.insertMiaoshaOrder(miaoshaOrder);

redisService.set(OrderKey.getMiaoshaOrderByUidGid, ""+user.getId()+"_"+goods.getId(), miaoshaOrder);

return orderInfo;
}

我觉得这两句话虽然在一个事务里，但是第一句里用了 where，虽然库存已经没了，但是没有报异常，导致 return 那句的订单还是可以生成。
//减库存下订单写入秒杀订单
goodsService.reduceStock(goods);
//order_info maiosha_order
return orderService.createOrder(user, goods);

2020-07-10 17:25:57 +08:00

回复了 chwangtenger 创建的主题 › MySQL › mysql update 库存解决并发卖超的问题失败了 where and 真的可行吗？

@limuyan44 对，sql 没问题的，但是影响的行是 0 行，也不会报出异常，所以后面的程序代码里顶多只能自己判断返回的影响行数来判断刚才的减库存有没有成功，但是他代码里也没这么写，我感觉老师不是讲错了。但是我又无法解释为啥他并发的结果是对的，一件都没超。