AssertionFailure：當Hibernate查詢對象時，有時會拋出null id

Question

我在Tomcat v2.2.0 EC2服務器上運行了Spring 4.2.4 / Hibernate 5.0.6。

我遇到的問題是服務器運行了一段時間（超過一天）后，我偶爾會收到以下異常消息

org.hibernate.AssertionFailure: null id in com.app.core.models.User entry (don't flush the Session after an exception occurs)
org.hibernate.event.internal.DefaultFlushEntityEventListener.checkId(DefaultFlushEntityEventListener.java:60)
org.hibernate.event.internal.DefaultFlushEntityEventListener.getValues(DefaultFlushEntityEventListener.java:175)
org.hibernate.event.internal.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:135)
org.hibernate.event.internal.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:216)
org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:85)
org.hibernate.event.internal.DefaultAutoFlushEventListener.onAutoFlush(DefaultAutoFlushEventListener.java:44)
org.hibernate.internal.SessionImpl.autoFlushIfRequired(SessionImpl.java:1251)
org.hibernate.internal.SessionImpl.list(SessionImpl.java:1767)
org.hibernate.internal.CriteriaImpl.list(CriteriaImpl.java:363)
com.app.core.dao.AbstractDao.queryBy(AbstractDao.java:57)
com.app.business.MainController.surveryPage(MainController.java:41)
sun.reflect.GeneratedMethodAccessor65.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:178)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:444)
org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:432)
org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)

對象Survery對象的所有者字段類型為User，因為異常指出id為null，檢查Datebase，則id不為null。 並實際上重新啟動服務器會使錯誤消失一段時間。

@Entity
@Table(indexes={@Index(columnList = "OWNER_ID", name = "OWNER_ID_INDEX")})
public class Survey extends Persistable{
...
@JsonIgnore
@ManyToOne
@JoinColumn(name = "OWNER_ID", nullable = true)
private User owner;
...
}

我正在執行的查詢操作是：

public List<T> queryBy(String field, Object val) {
    Session session = sessionFactory.getCurrentSession();
    Transaction transaction = session.beginTransaction();
    Criteria criteria = session.createCriteria(persistentClass);
    criteria.add(Restrictions.eq(field, val));
    @SuppressWarnings("unchecked")
    List<T> l = criteria.list();
    transaction.commit();
    return l;
}

實際上，我擔心如果在會話配置中做錯了什么，用於休眠的配置如下：

import org.apache.commons.dbcp2.BasicDataSource;
import org.hibernate.SessionFactory;
import org.reflections.Reflections;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Profile;
import org.springframework.orm.hibernate5.HibernateTemplate;
import org.springframework.orm.hibernate5.HibernateTransactionManager;
import org.springframework.orm.hibernate5.LocalSessionFactoryBuilder;
import org.springframework.transaction.annotation.EnableTransactionManagement;

import com.app.core.db.PersistableInterceptor;
import com.app.core.db.Persistable;
@Configuration 
@EnableTransactionManagement
@Profile("dev")
public class Config {
    ..... 

    @Bean
    public HibernateTemplate hibernateTemplate() {
        return new HibernateTemplate(sessionFactory());
    }

    @Bean
    public SessionFactory sessionFactory() {
        if (sessionFactory!= null){
            return sessionFactory;
        }
        Properties p = new Properties();
        p.put("hibernate.dialect", "org.hibernate.dialect.PostgreSQLDialect");
        p.put("connection_pool_size", "10");
        p.put("hibernate.current_session_context_class", "thread");
        p.put("show_sql", "true");
        p.put("hibernate.hbm2ddl.auto", "update");
        p.put("hibernate.default_schema", "app");
        p.put("hibernate.jdbc.batch_size", BATCH_SIZE);

        SessionFactory sessionFactory = new LocalSessionFactoryBuilder(getDataSource())
           .addAnnotatedClasses(ANNOTATED_CLASSES)
           .addProperties(p)
           .setInterceptor(new PersistableInterceptor())
           .buildSessionFactory();
        Config.sessionFactory = sessionFactory;
        return sessionFactory;
    }

    @Bean
    public HibernateTransactionManager hibTransMan(){
        return new HibernateTransactionManager(sessionFactory());
    }

    ..... 

}

有什么想法或建議嗎？

Answer 1

您正在將Hibernate托管事務與Spring托管事務混合在一起。 使用Spring事務管理抽象時，您不必使用特定於資源的事務

您已經通過@EnableTransactionManagenent啟用了Spring事務。 如果您的bean具有@Transactional批注，則將您的代碼重構為

public List<T> queryBy(String field, Object val) {
    Session session = sessionFactory.getCurrentSession();
    Criteria criteria = session.createCriteria(persistentClass);
    criteria.add(Restrictions.eq(field, val));
    @SuppressWarnings("unchecked")
    List<T> l = criteria.list();
    return l;
}

還要更改您的SessionFactory bean定義，以利用Spring提供的LocalSessionFactoryBean。 這為使用Spring抽象的事務管理提供了掛鈎。 例

 @Bean
   public LocalSessionFactoryBean sessionFactory() {
      LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();
      sessionFactory.setDataSource(dataSource());
      sessionFactory.setPackagesToScan(new String[] { "package.to.your.entity.classes" });
      sessionFactory.setHibernateProperties(hibernateProperties());

      return sessionFactory;
   }

@Bean
public DataSource dataSource(){
   //define datasource
}

private  Properties hibernateProperties() {
   //hibernate props
}