P37-基于Redis緩存的商戶類型列表查詢

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

    @Resource
    StringRedisTemplate stringRedisTemplate;
    @Override
    public Result queryTypeList() {
    String key = RedisConstants.SHOPTYPE_LIST_KEY;
    List<String> listCache = stringRedisTemplate.opsForList().range(key, 0, -1);
    // System.out.println(listCache);
    if(listCache != null && !listCache.isEmpty()) {
        // redis緩存中存在
        // list<string> -> list<shoptype>
        List<ShopType> shopTypes = listCache.stream()
                .map(str -> (ShopType)JSONUtil.toBean(str, ShopType.class, true))
                .sorted(Comparator.comparingInt(ShopType::getSort))
                .collect(Collectors.toList());
        return Result.ok(shopTypes);
    }
    // redis中不存在，查詢數(shù)據(jù)庫(kù)
    List<ShopType> list = query().orderByAsc("sort").list();
    if(list == null) {
        // 數(shù)據(jù)庫(kù)中不存在
        return Result.fail("商戶類型列表不存在??！");
    }
    // 數(shù)據(jù)庫(kù)中存在，放入redis緩存并返回
    // List<ShopType>轉(zhuǎn)為L(zhǎng)ist<String>存入redis
    List<String> strList = list.stream().map(JSONUtil::toJsonStr).collect(Collectors.toList());
    stringRedisTemplate.opsForList().leftPushAll(key,strList);
    return Result.ok(list);
}
}