在保存對象之前保存臨時實例，然後保存對象

我試圖保存MotoPayment對象。但我必須檢查客戶與代碼已經存在或沒有保存motopayment對象之前。在保存對象之前保存臨時實例，然後保存對象

public class MotoPaymentOrder extends BaseDocument { 

    @ManyToOne 
    @JoinColumn(name = "CUSTOMER") 
    private Customer customer; 

    @Column(name = "AMOUNT") 
    private Double amount = Double.valueOf(0); 

    @ManyToOne 
    @JoinColumn(name = "PAYMENTSTATUS") 
    protected SystemTypeLookupData status ; 

    @Column(name = "PNRNO") 
    private String pnrNo; 

    @Column(name = "RESERVATIONNO") 
    private String reservationNo; 

}

控制器方法

@RequestMapping(value = "/motopaymnetorder", method = RequestMethod.POST) 
    @ResponseBody public MotoPaymentOrder create(@RequestBody MotoPaymentOrder domain){ 
     prepareCustomer(domain.getCustomer()); 
     return (MotoPaymentOrder) baseDocumentService.saveDocument(domain); 
    }

的以下方法使用具有代碼存在，或不另外保存客戶對象來檢查客戶。

public void prepareCustomer(Customer customer){ 
     Customer existingCustomer = (Customer) appService.findOneWhere("WHERE o.code = '"+customer.getCode()+"'",Customer.class); 
     if(existingCustomer==null){ 
      customer.setType(ApplicationConstants.CustomerType.Person); 

      PersonCustomer personCustomer = new PersonCustomer(); 
      personCustomer.setEmail(customer.getCustomerEmail()); 
      personCustomer.setFirstName(customer.getPersonCustomer().getFirstName()); 
      personCustomer.setLastName(customer.getPersonCustomer().getLastName()); 
      personCustomer.setCustomer(customer); 

      customer.setPersonCustomer(personCustomer); 


     } 
    }

我得到異常以下，同時節省MotoPaymentOrder對象：

org.hibernate.TransientPropertyValueException: object references an unsaved transient instance - save the transient instance before flushing : com.erp.hospitality.domain.MotoPaymentOrder.customer -> com.erp.core.domain.common.Customer 
    at org.hibernate.engine.spi.CascadingActions$8.noCascade(CascadingActions.java:379) 
    at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:126) 
    at org.hibernate.event.internal.AbstractFlushingEventListener.cascadeOnFlush(AbstractFlushingEventListener.java:150) 
    at org.hibernate.event.internal.AbstractFlushingEventListener.prepareEntityFlushes(AbstractFlushingEventListener.java:141) 
    at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:74) 
    at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:38) 
    at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1282) 
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.flush(AbstractEntityManagerImpl.java:1300) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) 
    at java.lang.reflect.Method.invoke(Method.java:498)

來源

2017-09-22 boycod3

好讀。 https://vladmihalcea.com/2015/03/05/a-beginners-guide-to-jpa-and-hibernate-cascade-types/ –

嘗試手動保留臨時子對象，然後將其設置爲父對象。 –

假設爲MotoPaymentOrder，相關Customer不保留，該JPA將要堅持它，這不是由你來實現做法。你可以使用CascadeType.REFRESH來告訴hibernate如果你的實體沒有保存，該怎麼做。

@ManyToOne(cascade=CascadeType.REFRESH) 
@JoinColumn(name = "CUSTOMER") 
private Customer customer;

來源

2017-09-22 11:01:15

在保存對象之前保存臨時實例，然後保存對象

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