Postgresql，JPA，主键

Question

我有Postgresql + JPA和自动递增键的问题，我只是没有解决。我搜索了一半的一天，但没有任何作用。

在网上我找到了以下解决方案

@Entity(name="FAST_FEATURE")
@SequenceGenerator(name="scanIdGen", initialValue=1000,     
 sequenceName="scan_seq", allocationSize=1)
 public class FastFeature implements Serializable 
{
    @Id
    @SequenceGenerator(name="FAST_FEATURE_id_seq",
                   sequenceName="FAST_FEATURE_id_seq",
                   allocationSize=1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE,
                generator="FAST_FEATURE_id_seq")
    @Column(name = "id", updatable=false)
    private Long id=null;
    ....
}

稍后我尝试使用：

将实体持久化到EJB中

@Stateless
public class FastRestService {

@PersistenceContext(unitName="FastSearchServerPU")
EntityManager em;

@Context
private UriInfo uriInfo;
...

 @POST
 @Path("/feature")
 public Response createFeature(ServerFeature serverFeature)
 {
   ....
    FastFeature fastFeature=new FastFeature();
    ...
    em.persist(fastFeature);

 }

如果我运行它，我总是会收到错误消息：

javax.persistence.PersistenceException: Exception [EclipseLink-4002] 
(Eclipse Persistence Services - 2.6.1.qualifier):     
org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: org.postgresql.util.PSQLException: FEHLER: doppelter 
Schlüsselwert verletzt Unique-Constraint „fast_feature_pkey“ 
(double key value violates unique-constraint)
 Detail: Schlüssel „(id)=(1)“ existiert bereits.
Error Code: 0
Call: INSERT INTO FAST_FEATURE (id, DOES_EXIST, HARD_CONSTRAINT, NAME,     
FAST_FEATURE_SET_ID, FAST_FEATURE_TYPE) VALUES (?, ?, ?, ?, ?, ?)
bind => [6 parameters bound]
Query: InsertObjectQuery(ch.hslu.mse.fasttrack.model.FastFeature[ id=1 ])
    at     
org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl$1.handleException(EntityManagerSetupImpl.java:745)
at org.eclipse.persistence.transaction.AbstractSynchronizationListener.handleException(AbstractSynchronizationListener.java:275)
at org.eclipse.persistence.transaction.AbstractSynchronizationListener.beforeCompletion(AbstractSynchronizationListener.java:170)
at org.eclipse.persistence.transaction.JTASynchronizationListener.beforeCompletion(JTASynchronizationListener.java:68)
at com.sun.enterprise.transaction.JavaEETransactionImpl.commit(JavaEETransactionImpl.java:452)
at com.sun.enterprise.transaction.JavaEETransactionManagerSimplified.commit(JavaEETransactionManagerSimplified.java:854)
at com.sun.ejb.containers.EJBContainerTransactionManager.completeNewTx(EJBContainerTransactionManager.java:721)
at com.sun.ejb.containers.EJBContainerTransactionManager.postInvokeTx(EJBContainerTransactionManager.java:505)

感谢任何评论。

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