對象引用未保存的瞬態實例 - 在刷新Hibernate之前保存瞬態實例

Question

我正在使用Seam Framework。 我有2個實體：

Request.java

@Entity
@Table(name = "SRV_REQUEST")
public class Request {

private Long id;

@Id 
@Column(name = "ID_")
public Long getId() {
   return id;
}

和RequestEvent.java

@Entity
@Table(name = "SRV_REQUEST_EVENT")
public class RequestEvent {

private Long id;
private Request request;

@Id
@GeneratedValue
@Column(name = "ID_")
public Long getId() {
   return id;
}

@ManyToOne
public Request getRequest() {
   return request;
}

當我做這個交易時：

Request request = new Request();
// I have to set ID manually
request.setId(12345);

entityManager.persist(request);

RequestEvent event = new RequestEvent();
event.setRequest(request);

entityManager.persist(event);

我收到了這個錯誤：

object references an unsaved transient instance - save the transient instance before flushing: kz.gov.mci.ipsc.services.RequestEvent.request -> kz.gov.mci.ipsc.services.Request

Answer 1

試試這個

    Request request = new Request();
    // I have to set ID manually
    request.setId(12345);

    entityManager.persist(request);

    entityManager.flush();//this point is important

    RequestEvent event = new RequestEvent();
    event.setRequest(request);

    entityManager.persist(event);

Answer 2

嘗試在getRequest方法上添加{CascadeType.PERSIST，CascadeType.MERGE}