扩展spring应用程序上下文的最佳方法是什么？

Question

I need to extend spring applicatioContext xml file with new beans definitions and then add references to them to list, which is a property of one bean: Basic applicationContext xml file:

<bean id="myBean" class="com.example.MyBean">
    <property name="providers"> 
        <list>
            <ref bean="provider1">
        </list>
    </property>
</bean>
<bean id="provider1" class="com.example.Provider">

Depends on instance of application I have different providers, so I need to add them to the list. Now I have the additional beans definitions in database and use BeanFactoryPostProcessor to add them to the context and then add references to them to the list of providers. But I use @Transactional annotation on myBean and automatic transaction management ( tx:annotation-driven ) and because of using BeanFactoryPostProcessor the transaction annotations are not processed.

So I need another way to extend the application context and then the list of providers. What can I use?

My idea is to have xml file which at the beginning is empty and then fill it by data from database and then import it somehow in applicationContext. Is it possible?

Thanks for your help

Answer 1

Use @PostConstruct method in your MyBean class that loads and fills provider list from database.

@PostConstruct
public void initialize() {
    providers.addAll(providerService.findAll());
}

Put all database related code into Service/Dao class and annotate it with @Transactional annotation

Answer 2

You can override or extend the bean definitions in multiple ways. In short, here is one way..

main Application Context xml:

<bean id="myBaseBean" class="com.example.MyBean" abstract="true">
    <property name="providers"> 
        <list merge="true">
            <ref bean="provider1" />
        </list>
    </property>
</bean>
<!-- default bean definition -->
<bean id="myBean" parent="myBaseBean">
    <property name="providers"> 
        <list merge="true">
        </list>
    </property>
</bean>
<bean id="provider1" class="com.example.Provider">

Some extendedApplication Context xml:

<bean id="myBean" parent="myBaseBean">
        <property name="providers"> 
            <list merge="true">
                <ref bean="someOtherProvider" />
            </list>
        </property>
    </bean>
 <!-- bean definition of some other provider -->

This is nothing to do with Transactions You have to handle the transactions as usual for every other bean.

NOTE: All the application context files will be loaded/override based on the order of the file names you mention while creating the ApplicationContext .