java - 保存 BLOB 时为 "could not reset reader"

Question

我曾经使用 Hibernate 3，现在我正在迁移到 Hibernate 5，并且发生了一些问题(当然)。

我有几个通过 Hibernate 存储的 DAO 对象，其中一些具有“修改”的参数/字段/列，这些对象在 Hibernate 中每次保存/更新时都会自动更新为当前时间。

这是简单的 DAO:

@Entity
@Table(name="attachments")
@SequenceGenerator(name="common_attachments_seq", sequenceName="common_attachments_seq", allocationSize=1)
public class AttachmentDAO implements Modifications {
    private Long id;
    private String name;
    private Blob content;
    private Date modified;

    public AttachmentDAO() {}

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO, generator="common_attachments_seq")
    @Column(updatable = false, nullable = false)
    public Long getId() {return this.id;}
    public void setId(Long id) {this.id=id;}

    @Column
    public String getName() {return this.name;}
    public void setName(String name) {this.name=name;}

    @Column
    public Blob getContent() {return this.content;}
    public void setContent(Blob content) {this.content=content;}

    @Column
    public Date getModified() {return modified;}
    public void setModified(Date date) {modified=date;}
 }

这是设置修改监听器的集成器:

public class HibernateIntegrator implements Integrator {

  @Override
  public void integrate(Metadata metadata, SessionFactoryImplementor sessionFactory, SessionFactoryServiceRegistry serviceRegistry) {
      EventListenerRegistry eventListenerRegistry=serviceRegistry.getService(EventListenerRegistry.class);

      ModificationsEventListener mod=new ModificationsEventListener();

      eventListenerRegistry.appendListeners(EventType.UPDATE, mod);
      eventListenerRegistry.appendListeners(EventType.SAVE, mod);
      eventListenerRegistry.appendListeners(EventType.SAVE_UPDATE, mod);
  }

  @Override
  public void disintegrate(SessionFactoryImplementor sessionFactory, SessionFactoryServiceRegistry serviceRegistry) {
  }
}

这是 ModificationsEventListener，它实际上更新“已修改”参数:

public class ModificationsEventListener extends DefaultSaveOrUpdateEventListener {

@Override
public void onSaveOrUpdate(SaveOrUpdateEvent event) throws HibernateException {
    Object o=event.getObject();

    if (o instanceof Modifications) {
        Date now=new Date();
        Modifications doc=((Modifications)o);
        doc.setModified(now);
    }
    super.onSaveOrUpdate(event);
}

}

这是保存DAO的代码:

        // DiskFileItem currentFile = file uploaded to server - Apache's commons-fileupload-1.3.2.jar
        Session hibSession=null;
        Transaction tx=null;

        try {
            SessionFactory sf=AttachmentsSessionFactory.getSessionFactory();

            hibSession=sf.openSession();
            tx=hibSession.beginTransaction();

            AttachmentDAO stub=new AttachmentDAO();
            stub.setName(fileName);

            long length=currentFile.getSize();
            InputStream ins=currentFile.getInputStream(); // this is FileInputStream
            LobCreator lobs=Hibernate.getLobCreator(hibSession);
            Blob blob=lobs.createBlob(ins, length);
            stub.setContent(blob);

            hibSession.save(stub);

            tx.commit();

            ins.close();
            currentFile.delete();

        } catch (Exception ex) {
            if (tx!=null) tx.rollback();
            log.error("", ex);
        } finally {
            if (hibSession!=null&&hibSession.isOpen()) {
                hibSession.close();
            }
            hibSession=null;
        }

但是这段代码会抛出错误:

2017-05-12 11:20:38,253 ERROR [org.hibernate.engine.jdbc.spi.SqlExceptionHelper] (default task-127) could not reset reader
2017-05-12 11:20:38,254 ERROR [org.hibernate.internal.SessionImpl] (default task-127) HHH000346: Error during managed flush [could not update: [com.test.persistence.AttachmentDAO#38]]
2017-05-12 11:20:38,267 ERROR [com.gibon.qintegra.servlets.upload.AttachmentsUploadProgressListener] (default task-127) : org.hibernate.exception.GenericJDBCException: could not update: [com.gibon.qintegra.persistence.common.AttachmentDAO#38]
at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:47)
at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:109)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3111)
at org.hibernate.persister.entity.AbstractEntityPersister.updateOrInsert(AbstractEntityPersister.java:2961)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3341)
at org.hibernate.action.internal.EntityUpdateAction.execute(EntityUpdateAction.java:145)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:582)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:456)
at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:337)
at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:39)
at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1282)
at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:465)
at org.hibernate.internal.SessionImpl.flushBeforeTransactionCompletion(SessionImpl.java:2963)
at org.hibernate.internal.SessionImpl.beforeTransactionCompletion(SessionImpl.java:2339)
at org.hibernate.engine.jdbc.internal.JdbcCoordinatorImpl.beforeTransactionCompletion(JdbcCoordinatorImpl.java:485)
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.beforeCompletionCallback(JdbcResourceLocalTransactionCoordinatorImpl.java:147)
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl.access$100(JdbcResourceLocalTransactionCoordinatorImpl.java:38)
at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.commit(JdbcResourceLocalTransactionCoordinatorImpl.java:231)
at org.hibernate.engine.transaction.internal.TransactionImpl.commit(TransactionImpl.java:65)
at com.gibon.qintegra.servlets.upload.AttachmentsUploadProgressListener.currentFileFinished(AttachmentsUploadProgressListener.java:138)
at com.gibon.qintegra.data4ajax.AttachmentsServant.doServe(AttachmentsServant.java:255)
at com.gibon.qintegra.servlets.Data4Ajax.doProcess(Data4Ajax.java:74)
at com.gibon.qintegra.servlets.Data4Ajax.doPost(Data4Ajax.java:24)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
at com.gibon.qintegra.filters.IECompatFilter.doFilter(IECompatFilter.java:44)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at com.gibon.qintegra.filters.SecurityFilter.doFilter(SecurityFilter.java:89)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292)
at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:138)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:135)
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
at io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
at io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
at io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
at io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
at io.undertow.servlet.api.LegacyThreadSetupActionWrapper$1.call(LegacyThreadSetupActionWrapper.java:44)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:104)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:805)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.sql.SQLException: could not reset reader
at org.hibernate.engine.jdbc.BlobProxy.resetIfNeeded(BlobProxy.java:75)
at org.hibernate.engine.jdbc.BlobProxy.getUnderlyingStream(BlobProxy.java:64)
at org.hibernate.engine.jdbc.BlobProxy.getStream(BlobProxy.java:60)
at org.hibernate.engine.jdbc.BlobProxy.invoke(BlobProxy.java:101)
at com.sun.proxy.$Proxy118.getBinaryStream(Unknown Source)
at org.postgresql.jdbc.PgPreparedStatement.setBlob(PgPreparedStatement.java:1154)
at org.jboss.jca.adapters.jdbc.WrappedPreparedStatement.setBlob(WrappedPreparedStatement.java:1157)
at org.hibernate.type.descriptor.sql.BlobTypeDescriptor$4$1.doBind(BlobTypeDescriptor.java:132)
at org.hibernate.type.descriptor.sql.BasicBinder.bind(BasicBinder.java:74)
at org.hibernate.type.AbstractStandardBasicType.nullSafeSet(AbstractStandardBasicType.java:257)
at org.hibernate.type.AbstractStandardBasicType.nullSafeSet(AbstractStandardBasicType.java:252)
at org.hibernate.type.AbstractSingleColumnStandardBasicType.nullSafeSet(AbstractSingleColumnStandardBasicType.java:39)
at org.hibernate.persister.entity.AbstractEntityPersister.dehydrate(AbstractEntityPersister.java:2609)
at org.hibernate.persister.entity.AbstractEntityPersister.update(AbstractEntityPersister.java:3038)
... 67 more

hibernate执行的sql是这样的:

Hibernate: 
 select
     nextval ('common_attachments_seq')

Hibernate: 
 insert 
 into
     sys_attachments
     (content, modified, name, id) 
 values
     (?, ?, ?, ?)

Hibernate: 
 update
     sys_attachments 
 set
     content=?,
     modified=?,
     name=?,
 where
     id=?

显然问题是 Hibernate 插入记录并随后进行更新。 FileInputStream 不喜欢它，因为它在插入后立即关闭。
当我禁用集成器(更新“修改的”字段)时，它可以正常工作。

有什么办法让它发挥作用吗？

Answer 1

我刚刚看到这个:
How to autogenerate created or modified timestamp field?

它帮助我解决了我的问题。我必须在 Integrator 中使用 EventType.PRE_UPDATE 和 EventType.PRE_INSERT，而不是 EventType.SAVE_UPDATE、EventType.SAVE 和 EventType.UPDATE。然后更新这些监听器中的值，如下所示:

Modifications doc=((Modifications)entity);
doc.setModified(now);
setPropertyState(state, propertyNames, "modified", now);

属性状态 setter 在这里:

private void setPropertyState(Object[] propertyStates, String[] propertyNames, String propertyName, Object propertyState) {
    for(int i=0;i<propertyNames.length;i++) {
        if (propertyName.equals(propertyNames[i])) {
            propertyStates[i]=propertyState;
            return;
        }
    }
}