java - JPA双向映射不获取深度映射数据

Question

我有以下具有双向映射的 JPA 实体。我正在尝试将所有 featureGroup 提取到 DTO 中。

如果我在 featureGroup 上 findAll 并迭代以获取其功能。它不会来。我对 JPA 还不太熟悉。我的做法正确吗？

以下是我的实体。

@Entity
@Table(name="application")
@Data
class Application{
    @Id @GeneratedValue(strategy=GenerationType.IDENTITY) id;
    name;
    @OneToMany(mappedBy="application") 
    private Set<AppFeatureGroup> appFeatureGroup;
}

然后

@Entity
@Table(name="appfeaturegroup")
@Data
class AppFeatureGroup {
    @Id @GeneratedValue(strategy=GenerationType.IDENTITY) id;
    title;
    @OneToMany(mappedBy="appfeaturegroup")
    private Set<AppFeature> appFeature;
    @ManyToOne(cascade=CascadeType.ALL) @JoinColumn(name="id", insertable=false, updatable=false)
    private Application application;
}

然后

@Entity
@Table(name="appfeature")
@Data
class AppFeature{
    @Id @GeneratedValue(strategy=GenerationType.IDENTITY) id;
    title;
    @OneToMany(mappedBy="appFeature")
    private Set<AppSubFeature> appSubFeature;
    @ManyToOne(cascade=CascadeType.ALL) @JoinColumn(name="id", insertable=false, updatable=false)
    private AppFeatureGroup appFeatureGroup;
}

和

@Entity
@Table(name="appsubfeature")
@Data
class AppSubFeature{
    @Id @GeneratedValue(strategy=GenerationType.IDENTITY) id;
    title;
    @ManyToOne(cascade=CascadeType.ALL) @JoinColumn(name="id", insertable=false, updatable=false)
    private AppFeature appFeature;
}

然后

我尝试获取如下所示的对象:

List<AppFeatureGroup> appFeatureGroupList = appFeatureGroupRepository.finAll()
//Also tried from Application application = findById(id) and from application also I tried to get the deep objects

for(AppFeatureGroup appFeatureGroup : appFeatureGroupList){
    //I get id and title. But,
    Set<AppFeature> appFeature = appFeatureGroup.getAppFeature();//This is empty    
}

我的实现是不是不正确？我也尝试过使用 fetch=FethType.EAGER 。但还是不行。

Answer 1

我已从 lombok 中删除了 @Data。现在它工作正常。由于这个 lombok，我收到如下错误:

WARN  [org.hibernate.engine.loading.internal.LoadContexts] (default task-1) HHH000100: Fail-safe cleanup (collections) : org.hibernate.engine.loading.internal.CollectionLoadContext

另一个错误是这样的，

jpa Exception occurred: com.sun.jdi.InvocationException occurred invoking method..

当存在多个映射时，不要对 Entity 使用 @Data。