對象引用一個未保存的瞬態的實例 - 沖洗之前保存的瞬態的實例：春數據JPA

我有以下3種型號：對象引用一個未保存的瞬態的實例 - 沖洗之前保存的瞬態的實例：春數據JPA

模型1：預訂

@Entity 
    public class Reservation { 

     public static final long NOT_FOUND = -1L; 

     @Id 
     @GeneratedValue(strategy = GenerationType.IDENTITY) 
     public Long id; 

     @OneToMany(mappedBy = "reservation", cascade = CascadeType.ALL, orphanRemoval = true) 
     public List<RoomReservation> roomReservations = new ArrayList<>(); 
}

模型2：客房預訂：

public class RoomReservation extends{ 

     @Id 
     @GeneratedValue(strategy = GenerationType.IDENTITY) 
     public Long id; 

     @JsonIgnore 
     @ManyToOne(fetch = FetchType.LAZY) 
     @JoinColumn(name = "RESERVATION_ID") 
     public Reservation reservation; 

     @OneToMany(mappedBy = "roomReservation", cascade = CascadeType.ALL, orphanRemoval = true) 
     public List<GuestDetails> guestDetails = new ArrayList<>(); 
    }

模型3：來賓詳細介紹：

public class GuestDetails { 
    @Id 
    @GeneratedValue(strategy = GenerationType.IDENTITY) 
    public Long id; 

    public Long guestId; 

    @JsonIgnore 
    @ManyToOne(fetch = FetchType.LAZY) 
    @JoinColumn(name = "ROOM_RESERVATION_ID") 
    public RoomReservation roomReservation; 

    public Boolean isPrimary; 

    @Transient 
    public Guest guest; 

}

這三個之間的關係爲：

預訂 - 資助到許多關於RESERVATION_ID - >客房預訂 - 資助到許多關於ROOM_RESERVATION_ID - >客戶詳細

我收到預約對象，並試圖更新客人信息，我收到以下錯誤：

org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : com.model.GuestDetails.roomReservation -> com.model.RoomReservation 
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1760) 
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1677) 
    at org.hibernate.jpa.internal.TransactionImpl.commit(TransactionImpl.java:82) 
    at org.springframework.orm.jpa.JpaTransactionManager.doCommit(JpaTransactionManager.java:517) 
... 73 common frames omitted

我已經改變了的CascadeType爲ALL中常見的問題，建議仍然得到同樣的error.Please DONOT使其複製我試圖realated這類問題的解決方案都已經問

請讓我知道我在做什麼錯誤。由於

代碼通過改變GuestDetails保存預約對象：

Reservation existingReservation = reservationRepository.findOne(reservationId); 
Reservation reservation = reservationParser.createFromJson(reservationNode); 
existingReservation.roomReservations.forEach(roomReservation -> { 
        RoomReservation updatedRoomReservation = reservation.roomReservations.stream().filter(newRoomReservation -> Objects.equals(roomReservation.id, newRoomReservation.savedReservationId)).findFirst().orElse(null); 
        if(updatedRoomReservation != null){ 
         roomReservation.guestDetails = updatedRoomReservation.guestDetails; 
        } 
       }); 
reservationRepository.save(existingReservation);

來源

2017-10-20 utsav anand

請發佈實際上正在進行保存的代碼 - 您試圖保存什麼類的類型？ – PaulNUK

@PaulNUK我已經添加了代碼塊，我正在使用save.Please看看。 –

@PaulNUK嗨，任何更新..？ –

GuestDetails - 添加所需的CasadeType：

@ManyToOne(fetch = FetchType.LAZY, cascade=CascadeType.ALL) 
@JoinColumn(name = "ROOM_RESERVATION_ID") 
public RoomReservation roomReservation;

RoomReservation - 添加nedded CascadeType的：

@JsonIgnore 
@ManyToOne(fetch = FetchType.LAZY, cascade=CascadeType.AL) 
@JoinColumn(name = "RESERVATION_ID") 
public Reservation reservation;

然後你需要使用for-each循環後/前堅持數據。取決於你safe() -Method。

Reservation reservation = reservationParser.createFromJson(reservationNode); 
entityManager.persist(reservation);

然後安全起來。告訴我你的結果。也許直接工作而不更改/添加cascadetypes。

來源

2017-10-23 07:29:28 LenglBoy

我已經嘗試將CascadeType.ALL添加到訪客詳細信息，並且在循環之後持久化對象仍然收到相同的錯誤。 –

您可以保存從Json的得到保留。 JPA將更新具有相同id的行。

你得到的錯誤是因爲guestDetails仍具有向updatedRoomReservation參考。如果你不想從JSON拯救整個預約，你必須確立正確的RoomReservation。

例如爲：

if(updatedRoomReservation != null){ 
    roomReservation.guestDetails = updatedRoomReservation.guestDetails; 
    guestDetails.forEach(guestDetail -> guestDetail.roomReservation = roomReservation); 
}

來源

2017-10-23 11:54:17 Tom

如果你正在使用JPA 2.0然後默認取類型一對多是懶惰。如果在你的lambda之後，你的updatedRoomReservation是null（如你在orElse中設置的那樣），那麼existingReservation.roomReservation.guestDetails永遠不會被加載，並且將爲空。

因此，當你保存existingReservation，你會得到錯誤。

來源

2017-10-24 14:52:03 Garima

... save the transient instance before flushing : 
    com.model.GuestDetails.roomReservation -> com.model.RoomReservation

清楚，RoomReservation包含在GuestDetails這種異常狀態，不存在於數據庫中（最有可能是id是null）。

一般，您可以通過解決這個例外：

節能RoomReservation實體節約GuestDetails
或作出之前cascade = CascadeType.ALL（或至少{CascadeType.MERGE, CascadeType.PERSIST}）爲@ManyToOneGuestDetail-->RoomReservation

Bu t個第一，我有幾個點的覆蓋：

不要在課堂上使用公共字段，這違反the encapsulation concept。
當你有一個雙向關聯，你可以設置關聯另一側的Setter方法。

對於你的情況，你應該改變RoomReservation類：

public class RoomReservation{ 

    //..... other lines of code 

    @OneToMany(mappedBy = "roomReservation", cascade = CascadeType.ALL, orphanRemoval = true) 
    private List<GuestDetails> guestDetails = new ArrayList<>(); 

    public void setGuestDetails(List<GuestDetails> guestDetails) { 

      this.guestDetails.clear(); 

      // Assuming that by passing null or empty arrays, means that you want to delete 
      // all GuestDetails from this RoomReservation entity 
      if (guestDetails == null || guestDetails.isEmpty()){ 
       return; 
      } 

      guestDetails.forEach(g -> g.setRoomReservation(this)); 
      this.guestDetails.addAll(guestDetails); 
    } 

    public List<GuestDetails> getGuestDetails() { 
     // Expose immutable collection to outside world 
     return Collections.unmodifiableList(guestDetails); 
    } 

    // You may add more methods to add/remove from [guestDetails] collection 
}

保存預約：

Reservation existingReservation = reservationRepository.findOne(reservationId); 
Reservation reservation = reservationParser.createFromJson(reservationNode); 
existingReservation.roomReservations.forEach(roomReservation -> { 
        Optional<RoomReservation> updatedRoomReservation = reservation.roomReservations.stream().filter(newRoomReservation -> Objects.equals(roomReservation.id, newRoomReservation.savedReservationId)).findFirst(); 
        if(updatedRoomReservation.isPresent()){ 
         // roomReservation already exists in the database, so we don't need to save it or use `Cascade` property 
         roomReservation.setGuestDetails(updatedRoomReservation.get().getGuestDetails()); 
        } 
       }); 
reservationRepository.save(existingReservation);

希望它能幫助！

來源

2017-10-29 12:30:10

對象引用一個未保存的瞬態的實例 - 沖洗之前保存的瞬態的實例：春數據JPA

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