[Redis]黑马点评-商铺类型缓存使用List（练习题）

public class ShopTypeServiceImpl extends ServiceImpl<ShopTypeMapper, ShopType> implements IShopTypeService {
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    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Override
    public Result getTypeList() {
        String key= RedisConstants.CACHE_SHOP_TYPE;
//        1.从缓存中获取商铺分类信息 range:获取一个指定范围的值
        List<String> tyepList = stringRedisTemplate.opsForList().range(key, 0, -1);
//        2.判断缓存中是否存在
        if (Objects.requireNonNull(tyepList).size() != 0) {
//            存在直接返回
            List<ShopType> types = new ArrayList<>();
            for (String type : tyepList) {
                ShopType shopType = JSONUtil.toBean(type, ShopType.class);
                types.add(shopType);
            }
           return Result.ok(types);
        }
//        不存在则查询数据
        List<ShopType> shopTypeList = this.query().orderByAsc("sort").list();
        if (shopTypeList == null) {
           return Result.fail("数据不存在!");
        }
//        将查询到数据添加到缓存中
        assert shopTypeList != null;
        for (ShopType type : shopTypeList) {
//           rightPush向一个集合右边添加数据
            stringRedisTemplate.opsForList().rightPush(key,JSONUtil.toJsonStr(type));
        }
//        返回数据
        return Result.ok(shopTypeList);
    }
}