NamedEntityGraph仍导致延迟加载异常

Question

我有以下实体结构：

Route: -one-to-many-> :Stop: <-many-to-many-> :Child: <-many-to-many-> :Contact

因此，我在每个实体类的顶部定义了以下命名实体图，这样我就可以优化我的查询，以确定我需要走多远：

路线：

@NamedEntityGraphs({
        @NamedEntityGraph(name = "Route.stop.child.contact",
                attributeNodes = {
                        @NamedAttributeNode(value = "stops", subgraph = "Stop.child.contact")
                }),
        @NamedEntityGraph(name = "Route.stop.child",
                attributeNodes = {
                        @NamedAttributeNode(value = "stops", subgraph = "Stop.child")
                }),
        @NamedEntityGraph(name = "Route.stop",
                attributeNodes = {
                        @NamedAttributeNode(value = "stops", subgraph = "Stop")
                })
})
public class Route {...}

停止：

@NamedEntityGraphs({
        @NamedEntityGraph(name = "Stop.child.contact",
                attributeNodes = {
                        @NamedAttributeNode(value = "children", subgraph = "Child.contact")
                }),
        @NamedEntityGraph(name = "Stop.child",
                attributeNodes = {
                        @NamedAttributeNode(value = "children", subgraph = "Child")
                }),
        @NamedEntityGraph(name = "Stop", attributeNodes = {})
})
public class Stop {...}

孩子：

@NamedEntityGraphs({
        @NamedEntityGraph(name = "Child.contact",
                attributeNodes = {
                        @NamedAttributeNode(value = "contacts", subgraph = "Contact")
                }),
        @NamedEntityGraph(name = "Child", attributeNodes = {})
})
public class Child {...}

联系人：

@NamedEntityGraphs({@NamedEntityGraph(name = "Contact", attributeNodes = {})})
public class Contact {...}

我在我的仓库类中使用它们：

@EntityGraph(value = "Route.stop.child.contact", type = EntityGraph.EntityGraphType.LOAD)
Optional<Route> findRouteStopsChildrenContactsByRouteId(short routeId);

然而，我看不到正在进行任何连接查询，当我试图访问stops的子级时，会抛出一个lazyinit异常。我的理解是，这就是如何使用实体图来优化查询（例如，当我必须为每个单独的站点取子对象时，n 1问题），但我没有运气让它工作。

关于我做错了什么有什么建议吗？

Answer 1

试试这个它对我有用。

@NamedEntityGraph(name = "Book.details", attributeNodes = @NamedAttributeNode("reviews"))
@Table(name = "Book")
public class Book  implements Serializable
{
    @OneToMany(cascade = CascadeType.ALL , mappedBy = "book" , fetch = FetchType.EAGER)
    //@OrderBy("no ASC")
    private List<Review> reviews ; 
}

2） 获取记录（内部使用左外连接）。

@EntityGraph(value = "Book.details", type = EntityGraphType.FETCH)
  List<Book> getBooksByAuthName(String aname);