java - 主 Hibernate session 自动关闭

Question

我有一个父实体和子实体，如下所示

@Entity
@Table(name = "PARENT")
public class Parent implements Comparable<Parent>, Serializable, Cloneable {

    private static final long serialVersionUID = 1584115734363172986L;

    public static final int NAME_LENGTH = 300;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "gen-seq")
    @GenericGenerator(name = "gen-seq", strategy = "native",
        parameters = {@Parameter(name = "sequence_name", value = "parent_id_seq")})
    private Long id;

    @OneToMany(mappedBy = "parent", cascade = CascadeType.ALL)
    @BatchSize(size = 50)
    @SortNatural
    private SortedSet<Child> child = new TreeSet<>();
}

子实体如下

@Entity
@Table(name = "Child")
@Inheritance(strategy= InheritanceType.JOINED)
public class Child implements Comparable<Object>, Serializable, Cloneable, Step<Child> {

    private static final long serialVersionUID = -9091312680432977997L;

    public static final int NAME_LENGTH = 255;

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO, generator = "gen-seq")
    @GenericGenerator(name = "gen-seq", strategy = "native",
        parameters = {@Parameter(name = "sequence_name", value = "child_id_seq")})
    private Long id;

    @ManyToOne()
    @JoinColumn(name = "parentId", nullable = false)
    private Parent parent;
}

我已经配置了Spring和Hibernate来处理数据库操作，并且为了处理Parent，我在serviceimpl类中添加了以下方法。

public void processParent(final Long parentId, String userEmail) throws Exception {
getHibernateTemplate().execute(new HibernateCallback<Set<Void>>() {
    public void doInHibernate(Session session) throws HibernateException    {
        Parent parent = (Parent) session.get(Parent.class, parentId);           
        if (parent!=null && parent.getChild()!=null) {
            for (Child child: parent.getChild()) {

                // here the session is still Open when I call
                child.getParent();

                //But when I call this
                Parent p = getParent(child.getParent().getId());

                //now here the session got closed automatically, and now I cannot process the parent object

                }
            }
        }
    }
}}

在上面的方法中，我在调用 child.getParent() 之前打开 session ，但是如果我调用下面的方法，该方法有另一个 session 本身不为 null，则返回下面的方法后，上面的方法中的 session 将自动变为 null。

public Parent getParent(final Long id) throws Exception {
Parent actionPoint = (Parent) getHibernateTemplate().execute(new HibernateCallback<Parent>() {

    /* (non-Javadoc)
    * @see org.springframework.orm.hibernate5.HibernateCallback#doInHibernate(org.hibernate.Session)
    */
    public Parent doInHibernate(Session session) throws HibernateException {
        Parent parent = (ActionPoint) session.get(Parent.class, id);

        //here also session is still open
        return parent;
    }
}}

任何人都可以帮助我如何修复主 session 不应关闭或变为空的问题。我知道这是一个配置问题，但我不知道应该配置什么。

提前致谢，因为过去两周我一直在努力解决这个问题。

Answer 1

您可以在方法上方添加@Transactional，事务将在方法结束时关闭。要启用 @Transactional 注释，您可以在 context-persistence.xml 中添加以下代码:

<tx:annotation-driven transaction-manager="transactionManager" />

<bean id="transactionManager"
    class="org.springframework.orm.hibernate5.HibernateTransactionManager">
    <property name="sessionFactory" ref="sessionFactory" />
</bean>
<!-- Session Factory -->
<bean id="sessionFactory"
    class="org.springframework.orm.hibernate5.LocalSessionFactoryBean">
    <property name="dataSource" ref="dataSource" />
    <!-- <property name="configLocation" value="classpath:hibernate.cfg.xml"/> -->
    <property name="hibernateProperties">
        <map>
            <entry key="hibernate.default_schema" value="${database.default_schema}" />
            <entry key="hibernate.hbm2ddl.auto" value="${hibernate.hbm2ddl.auto}" />
            <entry key="show_sql" value="true" />
            <entry key="hibernate.dialect" value="${hibernate.dialect}" />
            <entry key="transaction.factory_class" value="org.hibernate.transaction.JDBCTransactionFactory" />
        </map>
    </property>
</bean>