Hibernate为OneToMany集合检索null

Question

我的问题是,hibernate 在获取以下对象上的实例时的值中检索null@OneToMany Set organizationMemberCollection:

UserAccount.java:

@Entity
@Table(name="USER_ACCOUNT")
public class UserAccount {

    @Id
    @Column(name = "id", nullable = false)
    @SequenceGenerator(name = "generator", sequenceName = "USER_ACCOUNT_id_seq", allocationSize=1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "generator")
    private Long id;

    @Column(name = "EMAIL", nullable = false)
    private String email;

    @Column(name = "PASSWORD_HASH")
    private String passwordHash;

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "userAccount")
    private Set <OrganizationMember> organizationMemberCollection;

    ...

    /*
     * getters and setters
     */
}

这是"拥有"该关联的对象:

OrganizationMember.java:

@Entity
@Table(name="ORGANIZATION_MEMBER")
public class OrganizationMember{

    @Id
    @Column(name = "id", nullable = false)
    @SequenceGenerator(name = "generator", sequenceName = "ORGANIZATION_MEMBER_id_seq", allocationSize=1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "generator")
    private Long id;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "USER_ACCOUNT_ID", nullable = false)
    private UserAccount userAccount;    

    ...

    /*
     * getters and setters
     */
}

在这个应用程序中,我们有两种不同的配置:

• 生产,Hibernate连接到PostgreSQL数据库.这是prod的sessionFactory配置:

  <bean id="sessionFactory" class="org.springframework.orm.hibernate5.LocalSessionFactoryBean"> <property name="hibernateProperties"> <props> <prop key="hibernate.jdbc.batch_size">10</prop> <prop key="hibernate.show_sql">true</prop> <prop key="hibernate.cglib.use_reflection_optimizer">false</prop> </props> </property> ... </bean>

• 测试,其中Hibernate连接到内存HSQLDB数据库:

  <bean id="sessionFactory" class="org.springframework.orm.hibernate5.LocalSessionFactoryBean"> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect">org.hibernate.dialect.HSQLDialect</prop> <prop key="hibernate.show_sql">false</prop> <prop key="hibernate.cglib.use_reflection_optimizer">false</prop> <prop key="hibernate.hbm2ddl.auto">create-drop</prop> <prop key="hibernate.cache.use_second_level_cache">false</prop> <prop key="hibernate.cache.use_query_cache">false</prop> </props> </property> ... </bean>

此问题仅出现在测试配置中; 在生产配置中,一切都很顺利,我可以获得收藏.但是,当我在测试配置中获取UserAccount时,我会null进入organizationMemberCollection属性(不是空集).

通过谷歌和Hibernate的文档进行了几个小时的研究后,我仍然没有找到任何与相同问题/行为有关的帖子,所以我会失去一点点帮助,我将不胜感激!

如果需要,我当然可以提供更多信息,谢谢!

编辑:

测试高亮问题:

@Test
@Transactional
public void testFindUserAccount_OrganizationMemberCollectionFetching() {

    assertNotNull(userAccountDao.findUserAccount("user1@test.fr"));  //NoProblem
    assertNotNull(userAccountDao.findUserAccount("user1@test.fr").getCabinetMemberCollection());  //Fails

}

随着以下findUserAccount道

public UserAccount findUserAccount(String email) {
    if (email == null) {
        return null;
    }
    UserAccount userAccount = (UserAccount) this.sessionFactory
            .getCurrentSession().createCriteria(UserAccount.class)
            .add(Restrictions.eq("email", email).ignoreCase())
            .uniqueResult();
    if (userAccount == null) {
        throw new ObjectNotFoundException("UserAccount.notFound");
    } else {
        return userAccount;
    }
}

Answer 1

问题是数据库填充和测试在同一事务中运行,并且在这两个步骤之间没有清除hibernate缓存.

结果是,hibernate并没有真正将请求发送到数据库,而是命中了缓存并返回了对象而没有与映射关系进行任何连接.

可能的解决方案是:

• 在不同的Transaction中填充数据库.
• SessionFactory.getCurrentSession().clean();在人口之后清理会话.(如果需要,请刷新会话:) SessionFactory.getCurrentSession().flush();.

每种可能性都会强制下一个查询真正命中数据库,因此将发生连接并且映射的Collection将包含所需数据(如果连接没有结果,则为空,但无论如何Collection都没有null值).

在我看来,第一种解决方案更好,因为如果测试中出现问题,它不会回滚整个人口.