如何使Jpql查询在带有可选返回的Spring Jpa存储库中工作？

Question

我在JpaRepository中使用Jpql查询。问题是，每次使用可选返回调用方法时，都会出现以下错误：

java.lang.ClassCastException： class[Ljava.lang.Object；不能强制转换为类com.netpos.pagvendas.campaignuser.entity.活动用户（[Ljava.lang.Object；在加载器'bootstrap'的模块java.base中；com.netpos.pagvendas.campaignuser.entity.活动用户在加载器的未命名模块中org.springframework.boot.devtools.restart.classloader.RestartClassLoader@1c069e07）

这是我的Repository类，我尝试使用的方法是：

findByActivgnCodUniqueActivgnAndCodTanner（String codUnique运动，String codTrener）

@Repository
public interface CampaignUserRepository extends JpaRepository<CampaignUser, CampaignUserPk> {

    @Query("SELECT campaignUser, campaignUser.campaign from CampaignUser campaignUser " +
            "where campaignUser.codTenant = :codTenant " +
            "and campaignUser.flgFinished = false " +
            "and :now >= campaignUser.campaign.datStart and :now <= campaignUser.campaign.datEnd " +
            "order by campaignUser.datCreation ASC")
    List<CampaignUser> findActiveCampaign(String codTenant, ZonedDateTime now);

    @Query("SELECT campaignUser, campaignUser.campaign from CampaignUser campaignUser " +
            "where campaignUser.idtCampaign = :idtCampaign ")
    List<CampaignUser> findByIdtCampaign(long idtCampaign);

    @Query("SELECT campaignUser, campaignUser.campaign from CampaignUser campaignUser " +
            "where campaignUser.campaign.codUniqueCampaign = :codUniqueCampaign " +
            "and campaignUser.codTenant = :codTenant")
    Optional<CampaignUser> findByCampaignCodUniqueCampaignAndCodTenant(String codUniqueCampaign, String codTenant);
}

是否可以在JpaRepository中对Jpql查询使用Optional？

Answer 1

为什么选择中有两个对象？要通过单个查询加载带有活动的活动用户，必须以这种方式启动查询

从campaignUser campaignUser join fetch campaignUser中选择campaignUser。活动活动

或者甚至

来自CampaignUser CampaignUser加入获取CampaignUser。活动活动

 @Query("SELECT campaignUser from CampaignUser campaignUser join fetch campaignUser.campaign campaign " +
                "where campaign.codUniqueCampaign = :codUniqueCampaign " +
                "and campaignUser.codTenant = :codTenant")
 Optional<CampaignUser> findByCampaignCodUniqueCampaignAndCodTenant(String codUniqueCampaign, String codTenant);