我有一个 Spring Batch 应用程序，它具有通常每个批处理作业都会引用的 Spring 上下文配置。这样每个批处理作业都使用相同的实体管理器。
批处理上下文.xml：
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:batch="http://www.springframework.org/schema/batch"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:aop="http://www.springframework.org/schema/aop"
xsi:schemaLocation="http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.1.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/batch http://www.springframework.org/schema/batch/spring-batch-2.1.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">
<!-- ... -->
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="persistenceUnitName" value="myPersistenceUnit" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
</property>
<property name="packagesToScan" value="com.example.domain" />
<property name="jpaProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.Oracle10gDialect</prop>
<prop key="hibernate.cache.use_second_level_cache">true</prop>
<prop key="hibernate.cache.provider_class"> org.hibernate.cache.EhCacheProvider</prop>
<prop key="hibernate.max_fetch_depth">3</prop>
<prop key="hibernate.jdbc.fetch_size">100</prop>
<prop key="hibernate.jbc.batch_size">1000</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.use_sql_comments">false</prop>
</props>
</property>
</bean>
<!-- ... -->
</beans>
现在在我的特定批处理作业上下文（称为 ExampleBatch.xml）中，我想添加另一个包以扫描到已定义的 entityManagerFactory bean。这可能吗？
ExampleBatch.xml：
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:batch="http://www.springframework.org/schema/batch"
xmlns:util="http://www.springframework.org/schema/util"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.1.xsd
http://www.springframework.org/schema/batch http://www.springframework.org/schema/batch/spring-batch-2.1.xsd">
<!-- ... -->
<import resource="classpath:batch-context.xml" />
<bean id="entityManagerFactoryWithExtraPackages"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
parent="entityManagerFactory">
<!-- How do I override the packagesToScan property on the already defined entityManagerFactory bean?-->
<property
name="packagesToScan"
value ="com.example.domain,com.example.domain.abstraction"
/>
</bean>
<!-- ... -->
</beans>
我现在的方式行不通，因为它抱怨“ No unique bean of type [javax.persistence.EntityManagerFactory] is defined: expected single bean but found 2”
试图覆盖“packagesToScan”属性是在这种情况下采取的正确方法吗？有没有更好的方法来完成这种行为？
编辑：
我能够使用该功能完成我需要的property-override工作。下面是我使用的更新后的 ExampleBatch.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:batch="http://www.springframework.org/schema/batch"
xmlns:util="http://www.springframework.org/schema/util"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.1.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
http://www.springframework.org/schema/batch http://www.springframework.org/schema/batch/spring-batch-2.1.xsd">
<!-- ... -->
<import resource="classpath:batch-context.xml" />
<context:property-override properties-ref="entityManagerOverride"/>
<bean id="entityManagerOverride"
class="org.springframework.beans.factory.config.PropertiesFactoryBean">
<property name="properties">
<util:properties>
<prop key="entityManagerFactory.packagesToScan">com.example.domain,com.example.batch.module.domain</prop>
</util:properties>
</property>
</bean>
<!-- ... -->
</beans>
到目前为止，Spring 并没有对我大喊这是一个无效的配置。尚未确定这是否真的产生了预期的结果。
编辑2：
属性覆盖方法似乎不够用。这是一个有效的配置，但在运行时检查实体管理器后，如下所示：
for (EntityType<?> entity : manager.getMetamodel().getEntities()) {
String name = entity.getName();
System.out.println(name);
}
它仅包含来自 com.example.domain 包的实体。
有没有人有任何其他想法？