「Spring 源码分析」Aware

1. 进入 initializeBean(String beanName, Object bean, @Nullable RootBeanDefinition mbd)方法
   protected Object initializeBean(String beanName, Object bean, @Nullable RootBeanDefinition mbd) {
        // 安全管理器模式
        if (System.getSecurityManager() != null) {
            AccessController.doPrivileged(() -> {
                this.invokeAwareMethods(beanName, bean);
                return null;
            }, this.getAccessControlContext());
        } else {
            // Aware接口 的第一个调用点
            this.invokeAwareMethods(beanName, bean);
        }

        Object wrappedBean = bean;
        if (mbd == null || !mbd.isSynthetic()) {
            // 遍历所有的后处理器，得到ApplicationContextAwareProcessor后处理器，然后执行相应Aware对象处理
            wrappedBean = this.applyBeanPostProcessorsBeforeInitialization(bean, beanName);
        }

        try {
            this.invokeInitMethods(beanName, wrappedBean, mbd);
        } catch (Throwable var6) {
            throw new BeanCreationException(mbd != null ? mbd.getResourceDescription() : null, beanName, "Invocation of init method failed", var6);
        }

        if (mbd == null || !mbd.isSynthetic()) {
            wrappedBean = this.applyBeanPostProcessorsAfterInitialization(wrappedBean, beanName);
        }

        return wrappedBean;
    }
2. 进入 this.invokeAwareMethods(beanName, bean)方法
   // 这是对 Aware接口 的直接方法调用
   private void invokeAwareMethods(String beanName, Object bean) {
        // 如果bean是Aware类型（这里指的是实现Aware接口）
        if (bean instanceof Aware) {
            // 如果bean是BeanNameAware类型
            if (bean instanceof BeanNameAware) {
                // 设置bean名称
                ((BeanNameAware)bean).setBeanName(beanName);
            }

            // 如果bean是BeanClassLoaderAware类型
            if (bean instanceof BeanClassLoaderAware) {
                // 获取类加载器
                ClassLoader bcl = this.getBeanClassLoader();
                if (bcl != null) {
                    ((BeanClassLoaderAware)bean).setBeanClassLoader(bcl);
                }
            }
            
            // 如果bean是BeanFactoryAware类型
            if (bean instanceof BeanFactoryAware) {
                // 获取beanFactory工厂
                ((BeanFactoryAware)bean).setBeanFactory(this);
            }
        }

    }

1. 进入 postProcessBeforeInitialization(Object bean, String beanName)方法
   public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
       // 对bean类型进行判断
       if (!(bean instanceof EnvironmentAware) && !(bean instanceof EmbeddedValueResolverAware) && !(bean instanceof ResourceLoaderAware) && !(bean instanceof ApplicationEventPublisherAware) && !(bean instanceof MessageSourceAware) && !(bean instanceof ApplicationContextAware)) {
            return bean;
       } else {
           AccessControlContext acc = null;
           if (System.getSecurityManager() != null) {
               acc = this.applicationContext.getBeanFactory().getAccessControlContext();
           }
            
           // 安全管理器模式
           if (acc != null) {
               AccessController.doPrivileged(() -> {
                   this.invokeAwareInterfaces(bean);
                   return null;
               }, acc);
           } else {
               this.invokeAwareInterfaces(bean);
           }

           return bean;
       }
   }
2. 进入 this.invokeAwareInterfaces(bean)方法
   private void invokeAwareInterfaces(Object bean) {
        if (bean instanceof EnvironmentAware) {
            // 获取 Environment环境变量，可以通过 Environment环境变量 获取属性
            ((EnvironmentAware)bean).setEnvironment(this.applicationContext.getEnvironment());
        }

        if (bean instanceof EmbeddedValueResolverAware) {
            // 获取 Spring容器 加载的 properties文件 里面相应的属性值
            ((EmbeddedValueResolverAware)bean).setEmbeddedValueResolver(this.embeddedValueResolver);
        }

        if (bean instanceof ResourceLoaderAware) {
            // 获取资源加载器
            ((ResourceLoaderAware)bean).setResourceLoader(this.applicationContext);
        }

        if (bean instanceof ApplicationEventPublisherAware) {
            // 获取应用事件发布器
            ((ApplicationEventPublisherAware)bean).setApplicationEventPublisher(this.applicationContext);
        }

        if (bean instanceof MessageSourceAware) {
            // 获取文本信息
            ((MessageSourceAware)bean).setMessageSource(this.applicationContext);
        }

        if (bean instanceof ApplicationContextAware) {
            // 获取 ApplicationContext上下文容器
            ((ApplicationContextAware)bean).setApplicationContext(this.applicationContext);
        }

    }