代码如下：

@Service
public class ShopTypeServiceImpl extends ServiceImpl<ShopTypeMapper, ShopType> implements IShopTypeService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Override
    public Result queryShopType() {
        String key = CACHE_SHOP_TYPE_KEY;
        //1、从Redis中查询店铺类型
        String shopTypeJson = stringRedisTemplate.opsForValue().get(key);
        //2、判断是否存在
        if(StrUtil.isNotBlank(shopTypeJson)){
            //3、存在，直接返回
            List<ShopType> shopTypeList = JSONUtil.toList(shopTypeJson, ShopType.class);
            return Result.ok(shopTypeList);
        }
        //4、不存在，从数据库中查询
        List<ShopType> typeList = query().orderByAsc("sort").list();
        //5、不存在，返回错误
        if(typeList == null || typeList.isEmpty()){
            return Result.fail("店铺类型查询失败！");
        }
        //6、存在，写入Redis缓存
        stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(typeList));
        //7、返回结果
        return Result.ok(typeList);
    }
}