有關實現ApplicationContextAware接口，裏面setApplicationContext回調的理解（用圖理解）

    public class SpringtUtil implements ApplicationContextAware {
        /**
         * Spring應用上下文環境
         */
        private static ApplicationContext applicationContext;

        /**
         * 實現ApplicationContextAware接口的回調方法，設置上下文環境
         */
        @Override
        public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
            SpringContextUtil.applicationContext = applicationContext;
        }

    }

 

/**
*去掉部分代碼
*/
class ApplicationContextAwareProcessor implements BeanPostProcessor {

	private final ConfigurableApplicationContext applicationContext;

	private final StringValueResolver embeddedValueResolver;


	/**
	 * Create a new ApplicationContextAwareProcessor for the given context.
	 */
	public ApplicationContextAwareProcessor(ConfigurableApplicationContext applicationContext) {
		this.applicationContext = applicationContext;
		this.embeddedValueResolver = new EmbeddedValueResolver(applicationContext.getBeanFactory());
	}


	@Override
	@Nullable
	public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
	
		if (acc != null) {
			AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
				invokeAwareInterfaces(bean);
				return null;
			}, acc);
		}
		return bean;
	}

	private void invokeAwareInterfaces(Object bean) {
	
		if (bean instanceof ApplicationContextAware) {
			((ApplicationContextAware) bean).setApplicationContext(this.applicationContext);
		}
	}

}