JPA多對多堅持

我有一個NOTIFICATION表誰包含一個多對多的關聯：JPA多對多堅持

@Entity 
@Table(name="NOTIFICATION") 
@NamedQuery(name="Notification.findAll", query="SELECT f FROM Notification f") 
public class Notification { 

/** SOME COLUMN DEFINITION NOT IMPORTANT FOR MY CASE 
    COD, DATE, ID_THEME, ID_TYP, IC_ARCH, ID_CLIENT, INFOS, NAME, TITRE_NOT, ID_NOT 
**/ 

     @ManyToMany 
     @JoinTable(
      name="PJ_PAR_NOTIF" 
      , joinColumns={ 
       @JoinColumn(name="ID_NOTIF") 
       } 
      , inverseJoinColumns={ 
       @JoinColumn(name="ID_PJ_GEN") 
       } 
      ) 
     private List<PiecesJointesGen> piecesJointesGens; 
}

所以，我有一個關聯表稱爲PJ_PAR_NOTIF。

我試圖堅持一個Notification實體。這裏是來自Value Object的piecesJointesGens初始化：

@PersistenceContext(unitName="pu/middle") 

private EntityManager entityMgr; 

FoaNotification lFoaNotification = new FoaNotification(); 

for(PieceJointeGenVO lPJGenVO : pNotificationVO.getPiecesJointes()){ 
     PiecesJointesGen lPiecesJointesGen = new PiecesJointesGen(); 
     lPiecesJointesGen.setLienPjGen(lPJGenVO.getLienPieceJointeGen()); 
     lPiecesJointesGen.setIdPjGen(lPJGenVO.getIdPieceJointeGen()); 
     lNotification.getFoaPiecesJointesGens().add(lFoaPiecesJointesGen); 
} 

entityMgr.persist(pNotification);

堅持不起作用。 JPA爲我的通知對象的第一插入，這是確定：

insert 
into 
    NOTIFICATION 
    (COD, DATE, ID_THEME, ID_TYP, IC_ARCH, ID_CLIENT, INFOS, NAME, TITRE_NOT, ID_NOT) 
values 
    (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)

然後，JPA嘗試在我的關聯表中插入值，但piecesJointesGen不存在的時刻：

insert 
into 
    PJ_PAR_NOTIF 
    (ID_NOTIF, ID_PJ_GEN) 
values 
    (?, ?)

所以，我有這樣的錯誤：

GRAVE: EJB Exception: : java.lang.IllegalStateException: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.entities.PiecesJointesGen

有沒有辦法告訴JPA的PJ_PAR_NOTIF插入之前，插入piecesJointesGen？

來源

2015-07-21 user3469203

嘗試在'piecesJointesGens'映射中使用'@ManyToMany（cascade = CascadeType.PERSIST）'。 –

這就是它！謝謝@PredragMaric！ – user3469203

太棒了，我已經添加了它作爲答案，因爲它幫助。 –

修改piecesJointesGens映射到@ManyToMany(cascade = CascadeType.PERSIST)。

來源

2015-07-21 09:39:17

JPA多對多堅持

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