public S3QueryResultList<ActivityModel> getActivitysByAttachmentsType(UserModel userModel, String type, int num, String cursor) {
if (StringUtil.isEmpty(cursor)) return getActivitysByAttachmentsType(userModel, type, num);
Category category = new Category(type);
ActivityModelMeta meta = ActivityModelMeta.get();
ModelRefAttributeMeta<ActivityModel, ModelRef<UserModel>, UserModel> refMeta = meta.userModelRef;
CoreAttributeMeta<ActivityModel,Category> categoryMeta = meta.attachmentsType;