/**
 * spring上下文句柄
 */
public class SpringContextHolder implements ApplicationContextAware {
    /**
     * spring上下文
     */
    private static ApplicationContext applicationContext;
    
    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        SpringContextHolder.applicationContext=applicationContext;
    }
    
    /**
     * 獲取spring上下文
     * @return
     */
    public static ApplicationContext getApplicationContext(){
        return applicationContext;
    }
    
    /**
     * 獲取bean
     * @param name  bean名稱
     * @param <T>
     * @return
     */
    public static <T> T getBean(String name){
        if(applicationContext==null){
            return null;
        }
        return (T) applicationContext.getBean(name);
    }
    
    /**
     * 獲取bean
     * @param requiredType bean類型
     * @param <T>
     * @return
     */
    public static <T> T getBean(Class<T> requiredType){
        if(applicationContext==null){
            return null;
        }
        return applicationContext.getBean(requiredType);
    }
    
    /**
     * 獲取bean
     * @param name  bean名稱
     * @param requiredType  bean類型
     * @param <T>
     * @return
     */
    public static <T> T getBean(String name, Class<T> requiredType){
        if(applicationContext==null){
            return null;
        }
        return applicationContext.getBean(name,requiredType);
    }
}

<!-- spring上下文句柄 -->
<bean id="springContextHolder" class="com.sa.demo.spring.context.SpringContextHolder"/>

SpringContextHolder.getBean("xxxxxx");
SpringContextHolder.getBean("XXX.class")
SpringContextHolder.getBean("xxxxxx","XXX.class")

ApplicationContext applicationContext=SpringContextHolder.getApplicationContext();

/**
 * Set the ApplicationContext that this object runs in.
 * Normally this call will be used to initialize the object.
 * <p>Invoked after population of normal bean properties but before an init callback such
 * as {@link org.springframework.beans.factory.InitializingBean#afterPropertiesSet()}
 * or a custom init-method. Invoked after {@link ResourceLoaderAware#setResourceLoader},
 * {@link ApplicationEventPublisherAware#setApplicationEventPublisher} and
 * {@link MessageSourceAware}, if applicable.
 * @param applicationContext the ApplicationContext object to be used by this object
 * @throws ApplicationContextException in case of context initialization errors
 * @throws BeansException if thrown by application context methods
 * @see org.springframework.beans.factory.BeanInitializationException
 */
void setApplicationContext(ApplicationContext applicationContext) throws BeansException;

設(shè)置運(yùn)行該對(duì)象的ApplicationContext。
通常這個(gè)調(diào)用將用于初始化對(duì)象。
在填充普通bean屬性之后，在init回調(diào)之前調(diào)用

org.springframework.context.support.ApplicationContextAwareProcessor#postProcessBeforeInitialization

org.springframework.context.support.ApplicationContextAwareProcessor#invokeAwareInterfaces

private void invokeAwareInterfaces(Object bean) {
    if (bean instanceof EnvironmentAware) {
        ((EnvironmentAware) bean).setEnvironment(this.applicationContext.getEnvironment());
    }
    if (bean instanceof EmbeddedValueResolverAware) {
        ((EmbeddedValueResolverAware) bean).setEmbeddedValueResolver(this.embeddedValueResolver);
    }
    if (bean instanceof ResourceLoaderAware) {
        ((ResourceLoaderAware) bean).setResourceLoader(this.applicationContext);
    }
    if (bean instanceof ApplicationEventPublisherAware) {
        ((ApplicationEventPublisherAware) bean).setApplicationEventPublisher(this.applicationContext);
    }
    if (bean instanceof MessageSourceAware) {
        ((MessageSourceAware) bean).setMessageSource(this.applicationContext);
    }
    if (bean instanceof ApplicationContextAware) {
        ((ApplicationContextAware) bean).setApplicationContext(this.applicationContext);
    }
}

EnvironmentAware
EmbeddedValueResolverAware
ResourceLoaderAware
ApplicationEventPublisherAware
MessageSourceAware
ApplicationContextAware