子图可以引用另一个命名实体图吗？

Question

所以我找到了一些答案，一个说可以这样做，另一个说不行。这让我很困惑，因为当我尝试这样做时——我失败了。

我想要的是在子图中引用命名实体图，如下所示：

@Entity
@Table(name = "parent")
@NamedEntityGraphs({
    @NamedEntityGraph(
        name = "Parent.all",
        attributeNodes = {
            @NamedAttributeNode(value = "child", subgraph = "Child.all"), // here I am referencing graph specified in Child entity
        }
    )
})
public class ParentModel {

  @OneToOne(
      mappedBy = "parent",
      fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
  private ChildModel child;

}

@Entity
@Table(name = "child")
@NamedEntityGraphs({
    @NamedEntityGraph(
        name = "Child.all",
        attributeNodes = {
            @NamedAttributeNode(value = "grandChildren"),
        }
    )
})
public class ChildModel {

  @OneToOne(fetch = FetchType.LAZY)
  @JoinColumn(name = "parent_id")
  private ParentModel parent;

  @OneToMany(
      mappedBy = "child",
      fetch = FetchType.LAZY, cascade = CascadeType.ALL, orphanRemoval = true)
  private Set<GrandChild> grandChildren;

}

我想使用Spring数据存储库方法：

@EntityGraph(value = "Parent.all")
List<ParentAll> findAll();

但当我想引用grandChildren类似的内容时，我仍然遇到 LazyInitializationException parent.child.grandChildren（注意，一旦我手动将 @NamedSubgraph 添加到 Parent 实体 - 一切正常）。那么是否可以这样做以使代码更简洁并且不重复自己呢？我在这里错过了什么吗？

Answer 1

据我所知，您必须分别定义命名图和子图，因为子图必须是 NamedSubgraph 类型，而不是 NamedEntityGraph 类型。

@NamedEntityGraph(
    name = "Parent.all", attributeNodes = {
        @NamedAttributeNode(value = "child", subgraph = "Child.all")},
    subgraphs = {
        @NamedSubgraph(name = "Child.all", attributeNodes = @NamedAttributeNode("grandChildren"))}
)