在Spring 3.1中配置JDO？

Question

我过去常常让我所有的DAO都扩展JdoDaoSupport类，现在这个类就是deprecated in Spring 3.1。我已经创建了自己的AbstractJdoDao类，它包装了PersistenceManagerFactory和所有DAO。这是我应该做的吗？

同样在documentation on JDO中，PersistenceManagerFactory的直接实例化似乎不是默认选项，而是使用包装在TransactionAwarePersistenceManagerFactoryProxy中的LocalPersistenceManagerFactoryBean。如何正确地实例化这些beans并使它们与Spring的@Transactional注解一起工作。

下面是我的应用程序上下文中与持久性相关的部分：

<bean id="persistenceManagerFactoryProxy" class="org.springframework.orm.jdo.TransactionAwarePersistenceManagerFactoryProxy">
    <property name="targetPersistenceManagerFactory">
        <bean class="org.springframework.orm.jdo.LocalPersistenceManagerFactoryBean">
            <property name="jdoPropertyMap">
                <props>
                    <prop key="javax.jdo.PersistenceManagerFactoryClass">org.datanucleus.store.appengine.jdo.DatastoreJDOPersistenceManagerFactory</prop>
                    <prop key="javax.jdo.option.ConnectionURL">appengine</prop>
                    <prop key="javax.jdo.option.NontransactionalRead">true</prop>
                    <prop key="javax.jdo.option.NontransactionalWrite">false</prop>
                    <prop key="javax.jdo.option.RetainValues">false</prop>
                    <prop key="javax.jdo.option.DetachAllOnCommit">true</prop>
                    <prop key="javax.jdo.option.Multithreaded">true</prop>
                    <prop key="datanucleus.appengine.ignorableMetaDataBehavior">NONE</prop>
                </props>
            </property>
        </bean>
    </property>
    <property name="allowCreate" value="false" />
</bean>

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

<bean id="transactionManager" class="org.springframework.orm.jdo.JdoTransactionManager">
    <property name="persistenceManagerFactory" ref="persistenceManagerFactoryProxy" />
</bean>

现在，当我加载一个访问数据存储的页面时：

org.springframework.transaction.CannotCreateTransactionException: Could not open JDO PersistenceManager for transaction; nested exception is java.lang.IllegalStateException: No JDO PersistenceManager bound to thread, and configuration does not allow creation of non-transactional one here
    at org.springframework.orm.jdo.JdoTransactionManager.doBegin(JdoTransactionManager.java:369) ~[spring-orm-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.transaction.support.AbstractPlatformTransactionManager.getTransaction(AbstractPlatformTransactionManager.java:371) ~[spring-tx-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.createTransactionIfNecessary(TransactionAspectSupport.java:335) ~[spring-tx-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:105) ~[spring-tx-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:202) ~[spring-aop-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at $Proxy15.queryAll(Unknown Source) ~[na:na]
    ...
Caused by: java.lang.IllegalStateException: No JDO PersistenceManager bound to thread, and configuration does not allow creation of non-transactional one here
    at org.springframework.orm.jdo.PersistenceManagerFactoryUtils.doGetPersistenceManager(PersistenceManagerFactoryUtils.java:153) ~[spring-orm-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at org.springframework.orm.jdo.TransactionAwarePersistenceManagerFactoryProxy$PersistenceManagerFactoryInvocationHandler.invoke(TransactionAwarePersistenceManagerFactoryProxy.java:159) ~[spring-orm-3.1.0.RELEASE.jar:3.1.0.RELEASE]
    at $Proxy13.getPersistenceManager(Unknown Source) ~[na:na]
    at org.springframework.orm.jdo.JdoTransactionManager.doBegin(JdoTransactionManager.java:308) ~[spring-orm-3.1.0.RELEASE.jar:3.1.0.RELEASE]
... 73 common frames omitted

我找到my example project on GitHub了。它使用的是Google App Engine，所以要么在Eclipse中通过mvn gae:run运行它(使用Eclipse的Google Plugin )，首先通过mvn eclipse:eclipse创建一个Eclipse项目。

Answer 1

我的建议是按照Spring3.1文档的建议使用TransactionAwarePersistenceManagerFactoryProxy或SpringPersistenceManagerProxyBean。这似乎是为了替换JdoDaoSupport类而设计的。

虽然您在创建自己的AbstractJdoDao包装器的问题中提出的建议当然会消除弃用警告，但我唯一担心的是，您可能无意中造成了其他人很难维护的情况，因为它不是他们所习惯看到的。

另一方面，我认为创建自己的包装器是解决问题的一种非常快速的方法……

您应该仔细权衡使用自己的包装器的优缺点和继续使用Spring3.1的方式的优缺点。根据我的经验，走捷径可能而且经常会在未来再次困扰你。