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Dynamically create spring beans and alter properties on existing beans

Asked 2012-08-23T11:19:39.500
8

I sucessfully managed to implement dynamic changing of database connections by following http://blog.springsource.com/2007/01/23/dynamic-datasource-routing/ article.

But now the problem is, I have a list of database urls in a configuration file that is managed by a legacy application.

Is there a way to create beans in that Spring context from a list of values (i.e. Year2011DataSource, Year2012DataSource,...) and populate map of the dataSource bean with those beans that were just created?

<!-- Property file located in the legacy application's folder -->
<context:property-placeholder location="file:///D:/config.properties" />

<!-- Shared data source properties are read from the config.properties file -->
<bean id="parentDataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource" abstract="true">
    <property name="driverClassName" value="${db.driver}" />
    <property name="username" value="${db.user}" />
    <property name="password" value="${db.password}" />
</bean>

<!-- Database urls by year -->
<bean id="Year2012DataSource" parent="parentDataSource">
    <property name="url" value="jdbc:sqlserver://localhost;databaseName=DbName_v570_2012" />
</bean>
<bean id="Year2011DataSource" parent="parentDataSource">
    <property name="url" value="jdbc:sqlserver://localhost;databaseName=DbName_v570_2011" />
</bean>
<bean id="Year2010DataSource" parent="parentDataSource">
    <property name="url" value="jdbc:sqlserver://localhost;databaseName=DbName_v570_2010" />
</bean>
<!-- ... and so on, these should instead be populated dynamically ... -->

<!-- DbConnectionRoutingDataSource extends AbstractRoutingDataSource -->
<bean id="dataSource" class="someProject.DbConnectionRoutingDataSource">
    <prop
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1 Answer

1

============================================

By following Biju's tip I've got everything working like this:

============================================

"Database urls by year" section in the spring configuration is no more, beans are created in the BeanFactoryPostProcessor.

"dataSource" bean has it's properties set to dummy data that is replaced in the BeanFactoryPostProcessor:

<bean id="dataSource" class="someProject.DbConnectionRoutingDataSource">
    <property name="targetDataSources">
        <map key-type="String">
            <!-- Will be filled from the DatasourceRegisteringBeanFactoryPostProcessor -->
        </map>
    </property>
    <property name="defaultTargetDataSource" value="java:jboss/datasources/ExampleDS" />
</bean>

And this is the BeanFactoryPostProcessor implementation:

@Component
class DatasourceRegisteringBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
        InitialContext ic = new InitialContext();

        // read the list of available JNDI connections
        NamingEnumeration<?> list = ic.listBindings(getJndiDSRoot());
        HashSet<String> jndiDataSources = new HashSet<String>();
        while (list.hasMore()) {
            /*... (ommitted for simplicity) ...*/
            connectionsList.put(key, value);
        }            

        BeanDefinitionRegistry factory = (BeanDefinitionRegistry) beanFactory;
        BeanDefinitionBuilder datasourceDefinitionBuilder;

        // Create new beans
        for (Entry<Integer, String> e : connectionsList.entrySet()) {
            datasourceDefinitionBuilder = BeanDefinitionBuilder
                    .childBeanDefinition("parentDataSource")
                    .addPropertyValue("url", e.getValue());

            factory.registerBeanDefini
answered 2012-08-27T08:06:25.410

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