java - 尝试使用 Spring 以正确的顺序销毁 bean

Question

我有一个带有 Spring 的 Web 应用程序，它设置为创建我的 hibernate session 工厂(单例)以及 session 和事务(两者都是请求范围的)，但它以错误的顺序破坏了 session 和事务。我如何配置它以便在 session 之前销毁事务？这是我的 spring applicationContext.xml 文件:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN"
      "http://www.springframework.org/dtd/spring-beans-2.0.dtd">
<beans>
  <bean id="hibernateSessionFactory" scope="singleton"
    class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
    <property name="configLocation" value="classpath:hibernate.cfg.xml" />
  </bean>

  <!-- The per-http request hibernate session -->
  <bean id="hibernateSession" factory-bean="hibernateSessionFactory"
    factory-method="openSession" destroy-method="close" scope="request" />

  <!--  The per-http request transaction (i need this to be destroyed BEFORE the session) -->
  <bean id="hibernateTransaction" factory-bean="hibernateSession"
    factory-method="beginTransaction" destroy-method="commit" scope="request" />
</beans>

这是显示它在关闭事务之前关闭 session 的日志:

16111 [http-8080-3] DEBUG org.springframework.beans.factory.support.DisposableBeanAdapter  - Invoking destroy method 'close' on bean with name 'hibernateSession'
16111 [http-8080-3] DEBUG org.hibernate.jdbc.ConnectionManager  - releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]
16111 [http-8080-3] DEBUG com.mchange.v2.resourcepool.BasicResourcePool  - trace com.mchange.v2.resourcepool.BasicResourcePool@17e4dee [managed: 4, unused: 3, excluded: 0] (e.g. com.mchange.v2.c3p0.impl.NewPooledConnection@19a8416)
16111 [http-8080-3] DEBUG org.springframework.beans.factory.support.DisposableBeanAdapter  - Invoking destroy method 'commit' on bean with name 'hibernateTransaction'
16111 [http-8080-3] DEBUG org.hibernate.transaction.JDBCTransaction  - commit
16111 [http-8080-3] WARN  org.springframework.beans.factory.support.DisposableBeanAdapter  - Invocation of destroy method 'commit' failed on bean with name 'hibernateTransaction'
org.hibernate.SessionException: Session is closed

Answer 1

对于非单例范围的bean，destory 方法调用的顺序似乎完全失控了。来自文档(5.1.4 Using depends-on):

The depends-on attribute in the bean definition can specify both an initialization time dependency and, in the case of singleton beans only, a corresponding destroy time dependency

您可以创建一个辅助对象并将 bean 的创建和销毁委托(delegate)给它:

public class HelperObject
{
    private SessionFactory factory;
    private Session session;
    private Transaction tx;

    public void init()
    {
        session = factory.createSession();
        tx = session.beginTransaction();
    }

    public void destroy()
    {
        tx.commit();
        session.close();
    }

    ...
} 

--

<bean id = "helperObject" class = "HelperObject" scope = "request" init-method = "init" destroy-method = "destroy">
    <property name = "factory" ref = "hibernateSessionFactory" />
</bean>

<bean id="hibernateSession" factory-bean="helperObject" 
    factory-method="getSession" scope="request" /> 

<bean id="hibernateTransaction" factory-bean="helperObject" 
    factory-method="getTransaction" scope="request" />

而且，毕竟，这可能不是在 Spring 中管理 Hibernate session 和事务的最佳方式。考虑使用 Spring 的内置 Hibernate和 transactions支持。

编辑:那么，管理事务的正确方法是:

• 您不需要请求范围的 session 和 transaction bean
• 您不应在 org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean 返回的 session 工厂上调用 createSession。您可以将此 session 工厂注入(inject)到您的 bean 中，并在需要 session 时调用 getCurrentSession，它会正常工作。
• 您可以使用声明式事务管理(事务方法上的@Transactional 注释)。为了让它工作，你应该添加到你的配置中:

.

<bean id="transactionManager"
    class="org.springframework.orm.hibernate3.HibernateTransactionManager">
    <property name="sessionFactory" ref="hibernateSessionFactory"/>
</bean>

<tx:annotation-driven/>

• 有关详细信息，请参阅上面的链接