[一个简单的秒杀架构的演变]1. 传统方式

地址

Github：https://github.com/dolyw/SeckillEvolution
Gitee(码云)：https://gitee.com/dolyw/SeckillEvolution

1. 思路介绍

不做任何控制，按照流程进行检查库存，扣库存，下订单，这种方式会存在并发问题

2. 代码实现

在SeckillEvolutionController创建一个传统方式下订单入口的方法

SeckillEvolutionController

/**
 * 传统方式下订单
 * 
 * @param id 商品ID
 * @return com.example.common.ResponseBean
 * @throws Exception
 * @author wliduo[i@dolyw.com]
 * @date 2019/11/21 19:50
 */
@PostMapping("/createWrongOrder/{id}")
public ResponseBean createWrongOrder(@PathVariable("id") Integer id) throws Exception {
    Integer orderCount = seckillEvolutionService.createWrongOrder(id);
    return new ResponseBean(HttpStatus.OK.value(), "购买成功", orderCount);
}

在Service添加方法

ISeckillEvolutionService

/**
 * 传统方式的创建订单(并发会出现错误)
 * 
 * @param id
 * @return java.lang.Integer
 * @throws Exception
 * @author wliduo[i@dolyw.com]
 * @date 2019/11/22 14:21
 */
Integer createWrongOrder(Integer id) throws Exception;

ISeckillEvolutionService

/**
 * 传统方式(名称注入)
 */
@Autowired
@Qualifier("seckillTraditionService")
private ISeckillService seckillTraditionService;

@Override
@Transactional(rollbackFor = Exception.class)
public Integer createWrongOrder(Integer id)  throws Exception {
    // 检查库存
    StockDto stockDto = seckillTraditionService.checkStock(id);
    // 扣库存
    Integer saleCount = seckillTraditionService.saleStock(stockDto);
    if (saleCount <= 0) {
        throw new CustomException("扣库存失败");
    }
    // 下订单
    Integer orderCount = seckillTraditionService.createOrder(stockDto);
    if (saleCount <= 0) {
        throw new CustomException("下订单失败");
    }
    return orderCount;
}

然后创建一个ISeckillService的传统方式的实现类提供上面使用

SeckillTraditionServiceImpl

package com.example.seckill.impl;

import ...

/**
 * 传统方式(并发会出现错误)
 *
 * @author wliduo[i@dolyw.com]
 * @date 2019-11-20 18:03:33
 */
@Service("seckillTraditionService")
public class SeckillTraditionServiceImpl implements ISeckillService {

    @Autowired
    private StockDao stockDao;

    @Autowired
    private StockOrderDao stockOrderDao;

    @Override
    public StockDto checkStock(Integer id) {
        StockDto stockDto = stockDao.selectByPrimaryKey(id);
        if (stockDto.getCount() > 0) {
            return stockDto;
        }
        throw new CustomException("库存不足");
    }

    @Override
    public Integer saleStock(StockDto stockDto) {
        stockDto.setCount(stockDto.getCount() - 1);
        stockDto.setSale(stockDto.getSale() + 1);
        return stockDao.updateByPrimaryKey(stockDto);
    }

    @Override
    public Integer createOrder(StockDto stockDto) {
        StockOrderDto stockOrderDto = new StockOrderDto();
        stockOrderDto.setStockId(stockDto.getId());
        return stockOrderDao.insertSelective(stockOrderDto);
    }
}