P37作業(yè)：基于value為String實現(xiàn)的（業(yè)務(wù)邏輯都放在了Service中），僅供參考

@Service

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

??@Resource

??private StringRedisTemplate stringRedisTemplate;

??@Override

??public Result queryShopType() {

????// 1.從redis查詢商鋪

????String key = "cache:shop_type";

????String shopTypeJson = stringRedisTemplate.opsForValue().get(key);

????// 2.判斷是否存在

????if (StrUtil.isNotBlank(shopTypeJson)) {

??????// 3.緩存 命中

??????List<ShopType> typeList = JSONUtil.toList(shopTypeJson, ShopType.class);

??????return Result.ok(typeList);

????}

????// 4.緩存 未命中 根據(jù)id查詢數(shù)據(jù)庫

????List<ShopType> typeList = query().orderByAsc("sort").list();

????// 5.判斷商鋪是否存在

????if (typeList == null) {

??????// 6.不存在，給出錯誤信息

??????return Result.fail("店鋪類型不存在！");

????}

????// 7.存在，將商鋪信息數(shù)據(jù)寫入緩存

????stringRedisTemplate.opsForValue().set(key, JSONUtil.toJsonStr(typeList));

????stringRedisTemplate.expire(key, LOGIN_USER_TTL, TimeUnit.MINUTES);

????// 8.返回商鋪信息

????return Result.ok(typeList);

??}

}