spring 的那些 processors

spring筆記

spring 的那些 processors

BeanFactoryPostProcessor Allows for custom modification of an application context's bean definitions, adapting the bean property values of the context's underlying bean factory.

Application contexts can auto-detect BeanFactoryPostProcessor beans in their bean definitions and apply them before any other beans get created.

Useful for custom config files targeted at system administrators that override bean properties configured in the application context.

eg. PropertyPlaceholderConfigurer PropertySourcesPlaceholderConfigurer This class is designed as a general replacement for {@code PropertyPlaceholderConfigurer} in Spring 3.1 applications. It is used by default to support the {@code property-placeholder} element in working against the spring-context-3.1 XSD, whereas spring-context versions <= 3.0 default to {@code PropertyPlaceholderConfigurer} to ensure backward compatibility. See spring-context XSD documentation for complete details.

As of Spring 3.1, PropertySourcesPlaceholderConfigurer should be used preferentially over this implementation;

BeanPostProcessor Factory hook that allows for custom modification of new bean instances, e.g. checking for marker interfaces or wrapping them with proxies.

ApplicationContexts can autodetect BeanPostProcessor beans in their bean definitions and apply them to any beans subsequently created. Plain bean factories allow for programmatic registration of post-processors, applying to all beans created through this factory.

<p>Typically, post-processors that populate beans via marker interfaces or the like will implement {[@link](https://my.oschina.net/u/393) #postProcessBeforeInitialization}, while post-processors that wrap beans with proxies will normally implement {[@link](https://my.oschina.net/u/393) #postProcessAfterInitialization}.

DestructionAwareBeanPostProcessor Subinterface of {@link BeanPostProcessor} that adds a before-destruction callback.

he typical usage will be to invoke custom destruction callbacks on specific bean types, matching corresponding initialization callbacks.

InstantiationAwareBeanPostProcessor Subinterface of {@link BeanPostProcessor} that adds a before-instantiation callback, and a callback after instantiation but before explicit properties are set or autowiring occurs.

Typically used to suppress default instantiation for specific target beans, for example to create proxies with special TargetSources (pooling targets, lazily initializing targets, etc), or to implement additional injection strategies such as field injection.

BeanDefinitionRegistryPostProcessor

public interface BeanDefinitionRegistryPostProcessor extends BeanFactoryPostProcessor

Extension to the standard {@link BeanFactoryPostProcessor} SPI, allowing for the registration of further bean definitions <i>before</i> regular BeanFactoryPostProcessor detection kicks in. In particular, BeanDefinitionRegistryPostProcessor may register further bean definitions which in turn define BeanFactoryPostProcessor instances.