Hibernate抛出“找到了具有给定标识符的多行”，但之后不会再抛出

Question

我有一个历史表映射到ManyToOne关系视图的应用程序，如下所示

@Entity
@Table(name = "HISTORY_TABLE", schema = "MY_SCHEMA")
public class HAction implements Serializable {
...

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumns({    
    @JoinColumn(name = "ID_WHO", referencedColumnName = "ID_USER"),
    @JoinColumn(name = "CT_WHO", referencedColumnName = "CT_SEQUENCE")
    })
private VwUsers whoDidTheAction;

...

//Getters & Setters

}

运行应用程序时，遇到了著名的“找到了具有给定标识符的多行”。

因此，我进入调试以找出导致此问题的用户。事实上，它在数据库View对象上有一个副本。但是，在调试过程中，我偶然发现了以下“魔法”

不确定它是否与我的IDE有关，但当在intelliJ（Eclipse上显示）上使用代码检查器并发出以下命令时

hAction.getWhoDidTheAction().getId();

它给了我错误，但当第二次这样做时，在同一个显示“会话”上，没有发生错误，结果如预期的那样。

有人知道这种行为的根源吗？我找不到任何与此相关的东西。

完整的HAction类：

@Entity
@Table(name = "HISTORY_TABLE", schema = "MY_SCHEMA")
public class HAction implements Serializable {

 /**  */
 private static final long serialVersionUID = -294276241063426049 L;

 @Id
 @Column(name = "ID_HISTORY_TABLE")
 @SequenceGenerator(name = "SQ_HISTORY_TABLE", sequenceName = "MY_SCHEMA.SQ_HISTORY_TABLE", allocationSize = 1)
 @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "SQ_HISTORY_TABLE")
 private Long idHAction;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_ACTION", referencedColumnName = "ID_ACTION")
 private SAction action;

 @Transient
 private Long idActionTransient;

 @Enumerated(EnumType.STRING)
 @Column(name = "CS_OPERATION")
 private OperationEnum csOperation;

 @Temporal(TemporalType.TIMESTAMP)
 @Column(name = "DT_OPEARATION")
 private Date dhOPeration;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_USER", referencedColumnName = "ID_USER")
 private VwUser user;

 @Column(name = "CD_PROTOCOL")
 private String cdProtocol;

 @Temporal(TemporalType.DATE)
 @Column(name = "DT_PROTOCOL")
 private Date dtProtocol;

 @Column(name = "DS_ACTION")
 private String dsAction;

 @Temporal(TemporalType.DATE)
 @Column(name = "DT_PREDICTION")
 private Date dtPrediction;

 @Enumerated(EnumType.STRING)
 @Column(name = "CS_ORIGIN")
 private OriginEnum csorigin;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_REQUIRED_BY_SECTOR", referencedColumnName = "ID_SECTOR")
 private VwSector vwSector;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_REQUIRED_BY_HQ", referencedColumnName = "ID_HQ")
 private VwHq vwHq;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_REQUIRED_BY_LOCAL", referencedColumnName = "ID_LOCAL")
 private VwLocal vwLocal;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_REQUIRED_BY_ASSOC", referencedColumnName = "ID_ASSOC")
 private VwAssoc vwAssoc;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_REQUIRED_BY_INTER", referencedColumnName = "ID_INTER")
 private VwInter vwInter;

 @Column(name = "DAY_VL")
 private Double dayValue;

 @Column(name = "MAT_VAL")
 private Double matValue;

 @Column(name = "OP_VALUE")
 private Double opValue;

 @Column(name = "TERC_VALUE")
 private Double tercValue;

 @Column(name = "TERC_SERV_VALUE")
 private Double tercServValue;

 @Column(name = "PUB_VALUE")
 private Double pubValue;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_RESPONSIBLE", referencedColumnName = "ID_UNIT")
 private Units unit;

 //This is the first fragment
 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumns({
  @JoinColumn(name = "ID_BOSS", referencedColumnName = "ID_USER"),
  @JoinColumn(name = "CT_BOSS", referencedColumnName = "CT_SEQUENCE")
 })
 private VwUsers whoDidTheActionBoss;
 //
 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumns({
  @JoinColumn(name = "ID_SUB_BOSS", referencedColumnName = "ID_USER"),
  @JoinColumn(name = "CT_SUB_BOSS", referencedColumnName = "CT_SEQUENCE")
 })
 private VwUsers whoDidTheActionSubBoss;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_PHONE", referencedColumnName = "ID_PHONE")
 private VwPhone vwPhone;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_EMAIL", referencedColumnName = "ID_EMAIL")
 private VwEmail vwEmail;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_EMAIL_SUB_BOSS", referencedColumnName = "ID_EMAIL")
 private VwEmail vwEmailSubBoss;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_PHONE_SUB_BOSS", referencedColumnName = "ID_PHONE")
 private vwPhone vwPhoneSubBoss;

 @Column(name = "PROTOCOL")
 private String protocol;

 @Enumerated(EnumType.STRING)
 @Column(name = "CONN")
 private VwConn conn;

 @ManyToOne(fetch = FetchType.LAZY)
 @JoinColumn(name = "ID_TYPE", referencedColumnName = "ID_TYPE")
 private SType type;

 @OneToMany(fetch = FetchType.LAZY, mappedBy = "id.HAction")
 private List < SFiles > files;

 @OneToMany(fetch = FetchType.LAZY, mappedBy = "id.HAction")
 private List < SThemes > themes;

 @Column(name = "ST_ARCHIVED")
 private Character archived;

 @Temporal(TemporalType.DATE)
 @Column(name = "DT_VIG")
 private Date dtVig;

 /**
  * Create Object {@link HAction}.
  * 
  */
 public HAction() {}

 //Getters & Setters
}

Answer 1

在与一些同事进行了更深入的研究后，我被指出这可能是一种代理实现行为，而且确实如此。

在“getId（）”执行期间，代理类检查多对一关系是否满足，如果不满足，它将结果填充为第一个找到的结果的数据，然后抛出异常。这对于调试特别有用，因为它至少为您提供了一个重复对象。这是预期的行为。

由于我在内存中已经有一个对象，因此无需“重新搜索”数据库中的记录，因此“getId（）”方法返回第一个元素的id，并且不会引发异常，因为它没有再次查询数据库。

关于代理行为的一些解释可以在这里找到

关于惰性初始值设定项的一些信息可以在这里找到

感谢所有花时间帮助我的人。