Extension interface for Spring BeanFactoryPostProcessor

2 years ago
Ava Mitchell
2 minutes

Spring provides an extension interface called BeanFactoryPostProcessor, which allows for post-processing of the BeanFactory before it instantiates beans. By implementing this interface, one can make custom modifications and adjustments to the BeanFactory.

public interface BeanFactoryPostProcessor {

    /**
     * 在所有BeanDefinition加载完成后，但在Bean实例化之前调用
     * 可以通过该方法对BeanDefinition进行修改和调整
     * @param beanFactory
     * @throws BeansException
     */
    void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException;

}

When implementing the BeanFactoryPostProcessor interface in Java, you need to implement the postProcessBeanFactory method. This method is called after all BeanDefinitions have been loaded, but before the Beans are instantiated. Within this method, you have the ability to modify and adjust BeanDefinitions, such as adding new ones or modifying existing ones.

In order to carry out post-processing on the BeanFactory during the startup of the Spring container, the implementation classes extending the BeanFactoryPostProcessor interface need to be registered with the Spring container either through the Spring configuration file or programmatically.

Here is the sample code:

public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        // 在该方法中进行BeanFactory的后置处理
    }
}

<bean class="com.example.MyBeanFactoryPostProcessor" />

@Configuration
public class AppConfig {

    @Bean
    public static MyBeanFactoryPostProcessor myBeanFactoryPostProcessor() {
        return new MyBeanFactoryPostProcessor();
    }
}

It’s important to note that if there are multiple classes implementing the BeanFactoryPostProcessor interface, the order of their execution is uncertain. To specify the execution order, you can implement the Ordered interface or use the @Order annotation.

bannerAds