看源码过程中可以看到很多XXXAware，之前没去深究，直到看到有人面试阿里被问到这问题。才决定去了解一下。
（1）Aware是什么？
是一个接口，里面空白一片，没有任何方法，它是一个空荡荡的定义，一种标记。
（2）有什么用？
Aware的英文意思是“可感知”，它自身是一个空白的接口，但是它有很多实现类，所以它的功能其实就是可以让调用者获取到某些信息，例如：加载当前Bean的容器名，当前Bean在容器中的BeanName，获取一些文本信息和资源文件等等，去获取加载当前Bean的加载器信息，等等等等。
我们也可以自定义一些XXAware，去获取自己想要的信息。
（3）怎么用？
就按照上面说的，只要实现了Aware接口的，都是为了获取，感知某些信息。那么我们就假设需要获取当前Bean的name和class loader。看下怎么玩。
定义一个Service：
@Service
public class TestA implements BeanNameAware , BeanFactoryAware , BeanClassLoaderAware {
private String name;
private String factory;
private String classLoads;
@Override
public void setBeanName(String beanName){
name = beanName;
}
@Override
public void setBeanClassLoader(ClassLoader classLoader) {
classLoads = classLoader.toString();
}
@Override
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
factory = beanFactory.toString();
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getFactory() {
return factory;
}
public void setFactory(String factory) {
this.factory = factory;
}
public String getClassLoad() {
return classLoads;
}
public void setClassLoad(String classLoad) {
this.classLoads = classLoad;
}
@Override
public String toString() {
return "TestA{" +
"name='" + name + '\'' +
", factory='" + factory + '\'' +
", classLoad='" + classLoads + '\'' +
'}';
}
}
注意，实现了BeanNameAware , BeanFactoryAware , BeanClassLoaderAware三个接口，三者父亲都是Aware，根据我的意思，应该就是要获取 Bean Name ，Factory , ClassLoader了。
随便写个Controller，启动run, 调用一下这个Server的toString方法，看看能不能读取到：
TestA{
name='testA', factory='org.springframework.beans.factory.support.DefaultListableBeanFactory@6fd83fc1: defining beans [org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.event.internalEventListenerProcessor,org.springframework.context.event.internalEventListenerFactory,chatRoomApplication,org.springframework.boot.autoconfigure.internalCachingMetadataReaderFactory,chatRoom,jdbcTestController,testA,webSocketConfig,webSocketServer,serverEndpointExporter,org.springframework.boot.autoconfigure.AutoConfigurationPackages,org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration,propertySourcesPlaceholderConfigurer,org.springframework.boot.autoconfigure.websocket.servlet.WebSocketServletAutoConfiguration$TomcatWebSocketConfiguration,websocketServletWebServerCustomizer,org.springframework.boot.autoconfigure.websocket.servlet.WebSocketServletAutoConfiguration,org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryConfiguration$EmbeddedTomcat,tomcatServletWebServerFactory,org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration,servletWebServerFactoryCustomizer,tomcatServletWebServerFactoryCustomizer,org.springframework.boot.context.properties.ConfigurationPropertiesBindingPostProcessor,org.springframework.boot.context.internalConfigurationPropertiesBinderFactory,org.springframework.boot.context.internalConfigurationPropertiesBinder,org.springframework.boot.context.properties.BoundConfigurationProperties,org.springframework.boot.context.properties.ConfigurationBeanFactoryMetadata,server-org.springframework.boot.autoconfigure.web.ServerProperties,webServerFactoryCustomizerBeanPostProcessor,errorPageRegistrarBeanPostProcessor,org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration$DispatcherServletConfiguration,dispatcherServlet,spring.mvc-org.springframework.boot.autoconfigure.web.servlet.WebMvcProperties,org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration$DispatcherServletRegistrationConfiguration,dispatcherServletRegistration,org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration,org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration,taskExecutorBuilder,applicationTaskExecutor,spring.task.execution-org.springframework.boot.autoconfigure.task.TaskExecutionProperties,org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration,error,beanNameViewResolver,org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration$DefaultErrorViewResolverConfiguration,conventionErrorViewResolver,org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration,errorAttributes,basicErrorController,errorPageCustomizer,preserveErrorControllerTargetClassPostProcessor,spring.resources-org.springframework.boot.autoconfigure.web.ResourceProperties,org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$EnableWebMvcConfiguration,requestMappingHandlerAdapter,requestMappingHandlerMapping,welcomePageHandlerMapping,mvcConversionService,mvcValidator,mvcContentNegotiationManager,mvcPathMatcher,mvcUrlPathHelper,viewControllerHandlerMapping,beanNameHandlerMapping,routerFunctionMapping,resourceHandlerMapping,mvcResourceUrlProvider,defaultServletHandlerMapping,handlerFunctionAdapter,mvcUriComponentsContributor,httpRequestHandlerAdapter,simpleControllerHandlerAdapter,handlerExceptionResolver,mvcViewResolver,mvcHandlerMappingIntrospector,org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter,defaultViewResolver,viewResolver,requestContextFilter,org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration,formContentFilter,org.springframework.boot.autoconfigure.aop.AopAutoConfiguration$ClassProxyingConfiguration,org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,org.springframework.boot.autoconfigure.availability.ApplicationAvailabilityAutoConfiguration,applicationAvailability,org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,org.springframework.boot.autoconfigure.context.LifecycleAutoConfiguration,lifecycleProcessor,spring.lifecycle-org.springframework.boot.autoconfigure.context.LifecycleProperties,org.springframework.boot.autoconfigure.dao.PersistenceExceptionTranslationAutoConfiguration,persistenceExceptionTranslationPostProcessor,org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$Jackson2ObjectMapperBuilderCustomizerConfiguration,standardJacksonObjectMapperBuilderCustomizer,spring.jackson-org.springframework.boot.autoconfigure.jackson.JacksonProperties,org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$JacksonObjectMapperBuilderConfiguration,jacksonObjectMapperBuilder,org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$ParameterNamesModuleConfiguration,parameterNamesModule,org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration$JacksonObjectMapperConfiguration,jacksonObjectMapper,org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration,jsonComponentModule,org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration$StringHttpMessageConverterConfiguration,stringHttpMessageConverter,org.springframework.boot.autoconfigure.http.JacksonHttpMessageConvertersConfiguration$MappingJackson2HttpMessageConverterConfiguration,mappingJackson2HttpMessageConverter,org.springframework.boot.autoconfigure.http.JacksonHttpMessageConvertersConfiguration,org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration,messageConverters,org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration,spring.info-org.springframework.boot.autoconfigure.info.ProjectInfoProperties,org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration,taskSchedulerBuilder,spring.task.scheduling-org.springframework.boot.autoconfigure.task.TaskSchedulingProperties,org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration,spring.datasource-org.springframework.boot.autoconfigure.jdbc.DataSourceProperties,org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration,platformTransactionManagerCustomizers,spring.transaction-org.springframework.boot.autoconfigure.transaction.TransactionProperties,org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration,restTemplateBuilder,org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration$TomcatWebServerFactoryCustomizerConfiguration,tomcatWebServerFactoryCustomizer,org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration,org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration,characterEncodingFilter,localeCharsetMappingsCustomizer,org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration,multipartConfigElement,multipartResolver,spring.servlet.multipart-org.springframework.boot.autoconfigure.web.servlet.MultipartProperties,org.springframework.boot.autoconfigure.websocket.servlet.WebSocketMessagingAutoConfiguration]; root of factory hierarchy', classLoad='sun.misc.Launcher$AppClassLoader@18b4aac2'}
可以看到是成功了。所以这就是Aware告知的作用。当需要获取当前Bean的一些信息，不需要硬编码或者注入的方式去拿，通过定义好的接口，直接获取。接耦。
