时间戳

首页 > 解决方案 > Hibernate 不急切

java - Hibernate 不急切

问题描述

我有两个类，“Article”，其中包含对“SurchargeGroup”的@ManyToOne 引用，该引用指定了该文章的附加费。

@Entity
@AllArgsConstructor
@NoArgsConstructor
@EqualsAndHashCode(doNotUseGetters = true)
@Audited
public final class Article {

  @Id
  @GeneratedValue(generator = "increment")
  @GenericGenerator(name = "increment", strategy = "increment")
  @Getter(onMethod_ = {@Key(PermissionKey.ARTICLE_ID_READ)})
  @Setter(onMethod_ = {@Key(PermissionKey.ARTICLE_ID_WRITE)})
  private int id;


  @JoinColumn(nullable = false)
  @ManyToOne
  @Getter(onMethod_ = {@Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_READ)})
  @Setter(onMethod_ = {@Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_WRITE)})
  private SurchargeGroup surchargeGroup;

}

另一个类“SurchargeGroup”包含一个父对象引用，如果未设置任何父级不提供附加费的情况，则可以将附加费继承到“SurchargeGroup”。


@Table
@Entity
@EqualsAndHashCode(doNotUseGetters = true)
@Audited
public class SurchargeGroup implements Serializable, Cloneable {

  @Id
  @GeneratedValue(strategy = GenerationType.AUTO)
  @Column
  @Getter(onMethod_ = {@Key(PermissionKey.SURCHARGE_TABLE_ID_READ)})
  @Setter(onMethod_ = {@Key(PermissionKey.SURCHARGE_TABLE_ID_WRITE)})
  private int id;

  @Column
  @Setter(onMethod_ = {@Key(PermissionKey.SURCHARGE_TABLE_SURCHARGE_WRITE)})
  private Double surcharge;

  @Column
  @Getter(onMethod_ = {@Key(PermissionKey.SURCHARGE_TABLE_NAME_READ)})
  @Setter(onMethod_ = {@Key(PermissionKey.SURCHARGE_TABLE_NAME_WRITE)})
  private String name;

  @JoinColumn
  @ManyToOne(fetch = FetchType.EAGER)
  @Getter(onMethod_ = {@Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_READ)})
  @Setter(onMethod_ = {@Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_WRITE)})
  private SurchargeGroup parent;

  public double getSurcharge() {
    if (surcharge == null) {
      return parent == null
          ? supplier == null
              ? Setting.SURCHARGE_DEFAULT.getDoubleValue()
              : supplier.getDefaultSurcharge()
          : parent.getSurcharge();
    } else return surcharge;
  }

 @JoinColumn
  @ManyToOne
  @Getter(onMethod_ = {@Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_READ)})
  @Setter(onMethod_ = {@Key(PermissionKey.SURCHARGE_TABLE_SUPPLIER_WRITE)})
  private Supplier supplier;
}

我现在的问题是，如果我调用“getSurcharge()”方法，我会得到这个异常，我无法向自己解释，因为我将附加费组标记为急切

Exception in thread "AWT-EventQueue-0" org.hibernate.LazyInitializationException: could not initialize proxy [kernbeisser.DBEntities.SurchargeGroup#1046] - the owning Session was closed
    at org.hibernate.proxy.AbstractLazyInitializer.initialize(AbstractLazyInitializer.java:172)
    at org.hibernate.proxy.AbstractLazyInitializer.getImplementation(AbstractLazyInitializer.java:309)
    at org.hibernate.proxy.pojo.bytebuddy.ByteBuddyInterceptor.intercept(ByteBuddyInterceptor.java:45)
    at org.hibernate.proxy.ProxyConfiguration$InterceptorDispatcher.intercept(ProxyConfiguration.java:95)
    at kernbeisser.DBEntities.SurchargeGroup$HibernateProxy$cdTAuBkS.getSurcharge(Unknown Source)

我问自己这是否可能是由 @Audited 注释引起的？有任何想法吗？非常感谢！

注意：@Key 注释对这种情况没有影响。

这是调试器显示的内容（对于德语 toString() 函数，抱歉）： 这是调试器显示的

标签： javahibernate

解决方案

Hibernate 需要在某个时候停止急切地获取关联，否则它需要无限次地加入SurchargeGroup实体（因为它引用了自身）。

hibernate.max_fetch_depth可以使用该属性在应用程序范围内控制这些提取的深度。

推荐阅读