示例二获取配置文件值配置文件application.properties内容定义工具类ConfigUtilcontroller测试调用运行示例二

示例三实现ResourceLoaderAware读取文件ExtendResourceLoaderAware

文件内容token.json

spring容器中Bean的生命周期内所有可扩展的点的调用顺序

扩展接口

实现接口ApplicationContextlnitializer

initialize

BeanDefinitionRegistryPostProcessor

postProcessBeanDefinitionRegistry

BeanDefinitionRegistryPostProcessor

instantiationAwareBeanPostProcessor

SmartlnstantiationAwareBeanPostProcessor

MergedBeanDefinitionPostProcessor

postProcessMergedBeanDefinition

InstantiationAwareBeanPostProcessor

SmartInstantiationAwareBeanPostProcessor

BeanNameAware

ApplicationContextAwareProcessor

InstantiationAwareBeanPostProcessor

afterPropertiesSet

今天要介绍的是ApplicationContextAwareProcessor

ApplicationContextAwareProcessor

分别为

EnvironmentAwareEmbeddedValueResolverAwareResourceLoaderAwareApplicationEventPublisherAwareMessageSourceAwareApplicationStartupAwareApplicationContextAware

1、EnvironmentAware凡注册到Spring容器内的bean实现了EnvironmentAware接口重写setEnvironment方法后在工程启动时可以获得application.properties的配置文件配置的属性值。

2、EmbeddedValueResolverAware用于获取StringValueResolver的一个扩展类

StringValueResolver用于获取基于String类型的properties的变量

3、ResourceLoaderAware用于获取ResourceLoader的一个扩展类ResourceLoader可以用于获取classpath内所有的资源对象可以扩展此类来拿到ResourceLoader对象。

4、ApplicationEventPublisherAware用于获取ApplicationEventPublisher的一个扩展类ApplicationEventPublisher可以用来发布事件结合ApplicationListener来共同使用

5、MessageSourceAware用于获取MessageSource的一个扩展类MessageSource主要用来做国际化

6、ApplicationStartupAware要开始收集定制的StartupStep组件可以实现ApplicationStartupAware接口直接获得ApplicationStartup实例或者在注入点请求ApplicationStartup类型。

7、ApplicationContextAware可以用来获取ApplicationContext的一个扩展类也就是spring上下文管理器可以手动的获取任何在spring上下文注册的bean

源码分析

从下列源码的invokeAwareInterfaces方法可知ApplicationContextAwareProcessor关联了大部分Spring内置Aware接口,它们的执行顺序如

下源码码所示从上到下最开始是EnvironmentAware最后是ApplicationContextAware

package

org.springframework.context.support;class

ApplicationContextAwareProcessor

implements

ApplicationContextAwareProcessor

for

ApplicationContextAwareProcessor(ConfigurableApplicationContext

applicationContext)

applicationContext;this.embeddedValueResolver

new

EmbeddedValueResolver(applicationContext.getBeanFactory());}OverrideNullablepublic

Object

postProcessBeforeInitialization(Object

bean,

this.applicationContext.getBeanFactory().getAccessControlContext();}if

(acc

{AccessController.doPrivileged((PrivilegedActionObject)

{invokeAwareInterfaces(bean);return

null;},

{invokeAwareInterfaces(bean);}return

bean;}private

bean).setEnvironment(this.applicationContext.getEnvironment());}if

(bean

bean).setEmbeddedValueResolver(this.embeddedValueResolver);}if

(bean

bean).setResourceLoader(this.applicationContext);}if

(bean

ApplicationEventPublisherAware)

{((ApplicationEventPublisherAware)

bean).setApplicationEventPublisher(this.applicationContext);}if

(bean

bean).setMessageSource(this.applicationContext);}if

(bean

bean).setApplicationStartup(this.applicationContext.getApplicationStartup());}if

(bean

bean).setApplicationContext(this.applicationContext);}}

}示例代码

ResourceLoaderAware,ApplicationEventPublisherAware,

MessageSourceAware,

setApplicationContext(ApplicationContext

applicationContext)

{log.info(setApplicationContext--Extend--run

{},applicationContext);}Overridepublic

void

setApplicationEventPublisher(ApplicationEventPublisher

{log.info(setApplicationEventPublisher--Extend--run

{},applicationEventPublisher);}Overridepublic

void

setApplicationStartup(ApplicationStartup

applicationStartup)

{log.info(setApplicationStartup--Extend--run

{},applicationStartup);}Overridepublic

void

setEmbeddedValueResolver(StringValueResolver

resolver)

{log.info(setEmbeddedValueResolver--Extend--run

void

{log.info(setEnvironment--Extend--run

{},environment);}Overridepublic

void

{log.info(setMessageSource--Extend--run

{},messageSource);}Overridepublic

void

setResourceLoader(ResourceLoader

resourceLoader)

{log.info(setResourceLoader--Extend--run

{},resourceLoader);}Overridepublic

void

{log.info(setBeanName--Extend--run

{},name);}

展示如何利用实现EmbeddedValueResolverAware来获取配置文件的属性值

db.usernavicat

db.driverClasscom.mysql.jdbc.Driver定义工具类ConfigUtil

Component

setEmbeddedValueResolver(StringValueResolver

resolver)

StringBuilder(${).append(key).append(});return

resolver.resolveStringValue(name.toString());}}controller测试调用

public

configUtil.getPropertiesValue(db.user);System.out.println(s);

}运行示例二

setResourceLoader(ResourceLoader

resourceLoader)

resourceLoader;log.info(ApplicationContextAware--Extend--run

void

resourceLoader.getResource(file:d:/token.json);InputStream

banner.getInputStream();BufferedReader

reader

null)break;System.out.println(line);}reader.close();}

}token.json

context;SuppressWarnings(resource)

public

Exception{ExtendResourceLoaderAware

context.getBean(extendResourceLoaderAware);extendResourceLoaderAware.showResourceData();

}运行示例三