java - HIbernate - 不要在急切关联中加载惰性实体

Question

如果我的项目中有以下类(class)

    @Entity
@Table(name = "application_home_screen")
public class ApplicationHomeScreenVO implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    private Integer id;

    @OneToOne(fetch = FetchType.EAGER)
    @Cascade({ CascadeType.ALL })
    @JoinColumn(name="image1_id")
    private ApplicationImageVO image1;

    @OneToOne(fetch = FetchType.EAGER)
    @Cascade({ CascadeType.ALL })
    @JoinColumn(name="image2_id")
    private ApplicationImageVO image2;  
}



@Entity
@Table(name = "application_image")
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class ApplicationImageVO implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    private Integer id;


    @OneToOne(fetch = FetchType.LAZY, mappedBy = "image1")
    @Cascade({ CascadeType.ALL })
    private ApplicationHomeScreenVO homeScreenImage1;   

    @OneToOne(fetch = FetchType.LAZY, mappedBy = "image2")
    @Cascade({ CascadeType.ALL })
    private ApplicationHomeScreenVO homeScreenImage2;

    @OneToOne(fetch = FetchType.LAZY, mappedBy = "otherEntity1")
    @Cascade({ CascadeType.ALL })
    private OtherEntity1 otherEntity1;

    @OneToOne(fetch = FetchType.LAZY, mappedBy = "otherEntity2")
    @Cascade({ CascadeType.ALL })
    private OtherEntity2 otherEntity2;

    @OneToOne(fetch = FetchType.LAZY, mappedBy = "otherEntity3")
    @Cascade({ CascadeType.ALL })
    private OtherEntity3 otherEntity3;

    @OneToOne(fetch = FetchType.LAZY, mappedBy = "otherEntity4")
    @Cascade({ CascadeType.ALL })
    private OtherEntity4 otherEntity3;
}

当我加载 ApplicationHomeVO - id 时，期望仅从 ApplicationImageVO 类加载 image1 和 image2，但事实并非如此

ApplicationImageVO 类中的所有其他对象也会被加载，即使它们被标记为 LAZY。我期望只加载 ApplicationHomeScreenVO 对象

有什么办法可以阻止这些其他实体被加载吗？

谢谢达米

Answer 1

@OneToOne 以这种方式声明是通过 PK 映射的，并且必须急切地获取它......

你可以:

• 将其设为@ManyToOne(fetch=FetchType.LAZY)

或者

• 声明外键列:

@OneToOne(fetch = FetchType.LAZY)
@JoinColumn(名称=“fk”)
公共(public) T getT()

编辑

@Entity
@Table(name = "application_home_screen")
public class ApplicationHomeScreenVO implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    private Integer id;

    @OneToOne(fetch = FetchType.EAGER)
    @Cascade({ CascadeType.ALL })
    @JoinColumn(name="image1_id")
    private ApplicationImageVO image1;

    @OneToOne(fetch = FetchType.EAGER)
    @Cascade({ CascadeType.ALL })
    @JoinColumn(name="image2_id")
    private ApplicationImageVO image2;  
}



@Entity
@Table(name = "application_image")
@JsonIgnoreProperties({"hibernateLazyInitializer", "handler"})
public class ApplicationImageVO implements Serializable {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", unique = true, nullable = false)
    private Integer id;


    @OneToOne(fetch = FetchType.LAZY, mappedBy = "image1")
    @Cascade({ CascadeType.ALL })
    private ApplicationHomeScreenVO homeScreenImage1;   

    @OneToOne(fetch = FetchType.LAZY, mappedBy = "image2")
    @Cascade({ CascadeType.ALL })
    private ApplicationHomeScreenVO homeScreenImage2;

    @ManyToOne(fetch = FetchType.LAZY, mappedBy = "otherEntity1")
    @Cascade({ CascadeType.ALL })
    private OtherEntity1 otherEntity1;

    @ManyToOne(fetch = FetchType.LAZY, mappedBy = "otherEntity2")
    @Cascade({ CascadeType.ALL })
    private OtherEntity2 otherEntity2;

    @ManyToOne(fetch = FetchType.LAZY, mappedBy = "otherEntity3")
    @Cascade({ CascadeType.ALL })
    private OtherEntity3 otherEntity3;

    @ManyToOne(fetch = FetchType.LAZY, mappedBy = "otherEntity4")
    @Cascade({ CascadeType.ALL })
    private OtherEntity4 otherEntity3;
}