java - 动态创建 spring bean 并更改现有 bean 的属性

Question

我通过遵循 http://blog.springsource.com/2007/01/23/dynamic-datasource-routing/ 成功地实现了数据库连接的动态更改文章。

但现在的问题是，我在由遗留应用程序管理的配置文件中有一个数据库 url 列表。

有没有一种方法可以根据值列表(即 Year2011DataSource、Year2012DataSource 等)在 Spring 上下文中创建 bean 并使用刚刚创建的那些 bean 填充 dataSource bean 的映射？

<!-- 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">
    <property name="targetDataSources">
        <map key-type="int">
            <entry key="2011" value-ref="Year2011DataSource" />
            <entry key="2010" value-ref="Year2010DataSource" />
            <!-- ... and so on, these also should instead be populated dynamically ... -->
        </map>
    </property>
    <property name="defaultTargetDataSource" ref="Year2012DataSource" />
</bean>

Answer 1

我认为非常适合这个要求的是自定义 BeanFactoryPostProcessor - 读取遗留配置并在自定义 bean 工厂后处理器中生成数据源:

class MyDatasourceRegisteringBeanFactoryPostProcessor implements BeanFactoryPostProcessor {

    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
        //Read in details from legacy properties.. build custom bean definitions and register with bean factory
        //for each legacy property...
            BeanDefinitionBuilder datasourceDefinitionBuilder = BeanDefinitionBuilder.rootBeanDefinition(BasicDataSource.class).addPropertyValue("url", "jdbc..");
            beanFactory.registerBeanDefinition(datasourceDefinitionBuilder.getBeanDefinition());
    }
}