概述

秒杀系统中总需要在启动时将数据放到redis中，即缓存预热，在秒杀开始时则需要通过redis进行库存的扣减，为保证redis和mysql数据一致性，通过可通过定时任务将redis中的数据同步回mysql中

demo

我们知道Redis数据的key通常以类名:midKey:商品id进行设计，为此我们根据key取出数据来，更新到数据库即可

@Component
public class RedisToMySqlScheduled implements ApplicationRunner {

    @Autowired
    private GoodsService goodsService;
    @Autowired
    private RedisUtil redisUtil;
	//map用来做数据的缓存
    private Map<Long,Boolean> map = new ConcurrentHashMap<>();

    @Scheduled(cron = "15 05 11 * * ? ")
    public void redisDataToMySql(){

        if (!map.isEmpty()){
            map.entrySet().forEach(entry->{

                Integer count = redisUtil.get(GoodsKey.getSecondKillGoodsStock, ":" + entry.getKey(), Integer.class);
                goodsService.redisToMysql(count,entry.getKey());
            });
        }

    }

    @Override
    public void run(ApplicationArguments args) throws Exception {
		//取出全部数据
        List<GoodsVo> goodsVos = goodsService.listGoodsVo();

        goodsVos.forEach(e->{
            map.put(e.getId(),false);
        });

    }
}

service

public int redisToMysql(Integer count,Long goodId){
		return goodsDao.redisDataToMysql(count,goodId);
	}

mapper

@Update("update second_goods set stock_count = #{stockCount} where goods_id = #{goodsId}")
	int redisDataToMysql(@Param("stockCount")Integer stockCount,@Param("goodsId")Long goodsId);

demo地址