java - 如何使用 Hibernate 填充实体的两个字段？

Question

我正在构建一个 API 来返回两个字段:

{
    currentPoints: 325,
    badgeName: "Some Badge"
}

但是，我在使用 hibernate 来填充这两个字段时遇到了麻烦。我做了两次尝试，都抛出错误。这两个错误都可以在它们各自的存储库文件中找到。在第二次尝试中，我使用了 native=true并且能够使用 SELECT * 让它工作.但是，我试图只填充和返回实体的两个字段。
我想到的一个解决方案是使用带有 SELECT * 的第二种方法并创建另一个名为 response 的包。与 CurrentInfoResponse类，然后返回该类。但是，我想看看是否有办法使用我现有的模型来避免这种情况。
可能的解决方案:

@Getter
@AllArgsConstructor
public class CurrentInfoResponse{
    private Integer currentPoints;
    private String badgeName
}

封装结构:

Controller .java:

@GetMapping("/current-badge/{userId}")
public CurrentBadgeInfoModel getCurrentBadge(@PathVariable Integer userId){
    return currentBadgeInfoService.getCurrentBadge(userId);
}

ServiceImpl.java:

@Override
public CurrentBadgeInfoModel getCurrentBadge(Integer userId){
    return currentBadgeInfoRepository.getCurrentBadge(userId);
}

CurrentBadgeInfoModel.java:

@Getter
@Entity
@Table(name = "user_current_badge_info")
public class CurrentBadgeInfoModel {

    @Id
    @Column(name = "user_current_info_id")
    private Integer userCurrentBadgeInfo;

    @Column(name = "user_id")
    private Integer userId;

    @Column(name = "current_points")
    private Integer currentPoints;

    @ManyToOne
    @JoinColumn(name = "badge_id")
    private BadgeModel badgeModel;
}

徽章模型.java

@Getter
@Entity
@Table(name = "badge_info")
public class BadgeModel {
    @Id
    @JoinColumn(name= "badge_id")
    private Integer badgeId;

    @Column(name = "badge_name")
    private String badgeName;
}

Repository.java - 尝试 1:

@Repository
public interface CurrentBadgeInfoRepository extends JpaRepository<CurrentBadgeInfoModel, Integer> {

    @Query("SELECT cbim.currentPoints, cbim.badgeModel.badgeName FROM CurrentBadgeInfoModel cbim JOIN 
cbim.badgeModel WHERE cbim.userId=?1")
    CurrentBadgeInfoModel getCurrentBadge(Integer userId);
}

//Error: No converter found capable of converting from type [java.lang.Integer] to type [com.timelogger.model.CurrentBadgeInfoModel]

Repository.java - 尝试 2:

@Repository
public interface CurrentBadgeInfoRepository extends JpaRepository<CurrentBadgeInfoModel, Integer> {

    @Query(value = "SELECT current_points, badge_name FROM user_current_badge_info ucbi JOIN badge_info bi ON ucbi.badge_id=bi.badge_id WHERE user_id=?1", nativeQuery = true)
    CurrentBadgeInfoModel getCurrentBadge(Integer userId);
}

//Error: Column 'user_current_info_id' not found

Answer 1

使用 SELECT clause HQL 应该在这里帮助你。
如果你没有那个构造函数，你可以添加它

@Query("SELECT new CurrentBadgeInfoModel(cbim.currentPoints, cbim.badgeModel.badgeName) FROM CurrentBadgeInfoModel cbim JOIN 
cbim.badgeModel WHERE cbim.userId=?1")

注意 new CurrentBadgeInfoModel(cbim.currentPoints, cbim.badgeModel.badgeName)的用法