微服务单体服务-抢购/秒杀超卖现象

关注博主，索要git仓库完整源码

抢购前数据

库存表

订单表

核心代码

调用方接口

/**
 * @Author yqq
 * @Date 2022/05/28 10:10
 * @Version 1.0
 */
@RestController
@RequestMapping("/grab")
public class GrabOrderController {

    @Autowired
    private RestTemplate restTemplate;
    @GetMapping("/do/{goodId}")
    public String grabMysql(@PathVariable("goodId") int goodId,int userId){
        String url = "http://order-service"+"/grab/do/"+goodId+"?userId="+userId;
        restTemplate.getForEntity(url, String.class).getBody();
        return "成功";
    }
}

Order服务核心代码

/**
 * @Author yqq
 * @Date 2022/05/28 10:16
 * @Version 1.0
 */
@RestController
@RequestMapping("/grab")
public class GrabOrderController {

    //无锁
    @Autowired
    @Qualifier("grabNoLockService")
    private GrabService grabService;
    @GetMapping("/do/{goodId}")
    public String grabMysql(@PathVariable("goodId") int goodId,int userId){
        System.out.println("good:"+goodId+",userId:"+userId);
        grabService.grabOrder(goodId,userId);
        return "";
    }
}

grabNoLockService逻辑

/**
 * @Author yqq
 * @Date 2022/05/28 10:20
 * @Version 1.0
 */
@Service("grabNoLockService")
public class GrabNoLockServiceImpl implements GrabService {
    @Autowired
    private InventoryService inventoryService;
    @Override
    public String grabOrder(int goodId, int userId) {
        System.out.println("用户："+userId+" 执行抢单逻辑");
        boolean flag = inventoryService.grab(goodId,userId);
        if (flag)
            System.out.println("用户："+userId+" 抢单成功");
        else
            System.out.println("用户："+userId+" 抢单失败");
        return null;
    }
}

库存和订单逻辑代码

/**
 * @Author yqq
 * @Date 2022/05/28 10:14
 * @Version 1.0
 */
@Service
public class InventoryServiceImpl extends ServiceImpl<InventoryMapper, Inventory> implements InventoryService{
    @Autowired
    private InventoryMapper mapper;
    @Autowired
    private OrderMapper orderMapper;
    @Override
    public boolean grab(int goodId, int userId) {
        Inventory inventory = mapper.selectById(goodId);
        try {
            Thread.sleep(2000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        int num = inventory.getNum().intValue();
        System.out.println("num:"+num);
        if (num > 0){
            //扣减库存
            inventory.setNum(num-1);
            mapper.updateById(inventory);
            //新增订单
            Order order = new Order();
            order.setUserId(userId);
            order.setOrderStatus(1);
            order.setOrderDesc("用户："+userId+"抢到了iPhoneSE");
            orderMapper.insert(order);
            return true;
        }
        return false;
    }
}

工具压测

抢购后数据

10个线程执行完毕

库存表

库存扣减失败

订单表

订单表从库存表中抢购2个商品，结果10个线程都抢到了。。。。。。。so。。。。。。

肯定不能这么干，超卖了，超卖了，我想加把锁。。。。。。