关联博文：
AbstractApplicationContext中refresh方法详解
Spring中refresh分析之prepareRefresh方法详解
Spring中refresh分析之obtainFreshBeanFactory方法详解
Spring中refresh分析之prepareBeanFactory方法详解
Spring中refresh分析之postProcessBeanFactory方法详解
Spring中refresh分析之invokeBeanFactoryPostProcessors方法详解
Spring中refresh分析之registerBeanPostProcessors方法详解
Spring中refresh分析之initMessageSource方法详解
Spring中refresh分析之initApplicationEventMulticaster方法详解
Spring中refresh分析之onRefresh方法详解
Spring中refresh分析之registerListeners方法详解
Spring中refresh分析之finishBeanFactoryInitialization方法详解
Spring中refresh分析之finishRefresh方法详解
接上文Spring中refresh分析之obtainFreshBeanFactory方法详解我们分析过obtainFreshBeanFactory方法后，本文分析prepareBeanFactory方法。
该方法主要是对beanFactory做了一些基础设置的配置，比如BeanClassLoader、BeanExpressionResolver、ApplicationContextAwareProcessor、ApplicationListenerDetector监听器检测器以及默认的环境信息bean。并设置了哪些不需要自动注入以及哪些已经解析过可以直接使用。
① 方法概览
AbstractApplicationContext的prepareBeanFactory方法如下所示。
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) { // Tell the internal bean factory to use the context's class loader etc. // 设置类加载器，默认是RestartClassLoader beanFactory.setBeanClassLoader(getClassLoader()); //设置表达式解析器，比如SPEL语法就是该解析器内维护的SpelExpressionParser进行处理的 beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader())); //向Set<PropertyEditorRegistrar> propertyEditorRegistrars添加ResourceEditorRegistrar beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment())); // Configure the bean factory with context callbacks. // 为beanFactory配置一些回调，这些在bean实例化过程中会被触发 beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this)); // 向Set<Class<?>> ignoredDependencyInterfaces中添加对象如EnvironmentAware beanFactory.ignoreDependencyInterface(EnvironmentAware.class); beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class); beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class); beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class); beanFactory.ignoreDependencyInterface(MessageSourceAware.class); beanFactory.ignoreDependencyInterface(ApplicationContextAware.class); // BeanFactory interface not registered as resolvable type in a plain factory. // MessageSource registered (and found for autowiring) as a bean. //向Map<Class<?>, Object> resolvableDependencies放入 beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory); beanFactory.registerResolvableDependency(ResourceLoader.class, this); beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this); beanFactory.registerResolvableDependency(ApplicationContext.class, this); // Register early post-processor for detecting inner beans as ApplicationListeners. // 注册应用监听器检测器，如果实例化bean是ApplicationListener，则其将会被放入applicationListeners beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this)); // Detect a LoadTimeWeaver and prepare for weaving, if found. // 如果loadTimeWeaver 存在于beanFactory，则注册LoadTimeWeaverAwareProcessor // 并设置TempClassLoader为ContextTypeMatchClassLoader if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) { beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory)); // Set a temporary ClassLoader for type matching. beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader())); } // Register default environment beans. // 如果不包含environment，则注册单例bean，将会放到singletonObjects、registeredSingletons if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) { beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment()); } //如果不包含systemProperties，则注册单例bean，将会放到singletonObjects、registeredSingletons if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) { beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties()); } //如果不包含systemEnvironment，则注册单例bean，将会放到singletonObjects、registeredSingletons if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) { beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment()); } }
方法逻辑梳理如下：
设置类加载器，默认是RestartClassLoader；
设置表达式解析器StandardBeanExpressionResolver，比如SPEL语法就是该解析器内维护的SpelExpressionParser进行处理的；
向Set<PropertyEditorRegistrar> propertyEditorRegistrars添加ResourceEditorRegistrar；
注册beanPostProcessor如ApplicationContextAwareProcessor；
向Set<Class<?>> ignoredDependencyInterfaces中添加对象如EnvironmentAware、EmbeddedValueResolverAware、ResourceLoaderAware、ApplicationEventPublisherAware、MessageSourceAware、ApplicationContextAware；也就是说这些类将不会通过Autowired自动注入而是会被BeanFactory通过比BeanFactoryAware或者ApplicationContext通过ApplicationContextAware这种方式设置。
向Map<Class<?>, Object> resolvableDependencies放入BeanFactory、ResourceLoader、ApplicationEventPublisher、ApplicationContext；表示是已经解析的依赖可以直接使用。
注册应用监听器检测器，如果实例化bean是ApplicationListener，则其将会被放入applicationListeners；
如果loadTimeWeaver 存在于beanFactory，则注册LoadTimeWeaverAwareProcessor并设置TempClassLoader为ContextTypeMatchClassLoader
注册默认的环境信息bean如environment、systemProperties、systemEnvironment
② addBeanPostProcessor
关于AbstractBeanFactory的addBeanPostProcessor方法我们可以看一下，如下所示其会根据BeanPostProcessor 的接口类型来对hasInstantiationAwareBeanPostProcessors 、hasDestructionAwareBeanPostProcessors 进行标记。最后将beanPostProcessor放到了beanPostProcessors 里面(其是一个CopyOnWriteArrayList)。
@Override public void addBeanPostProcessor(BeanPostProcessor beanPostProcessor) { Assert.notNull(beanPostProcessor, "BeanPostProcessor must not be null"); // Remove from old position, if any this.beanPostProcessors.remove(beanPostProcessor); // Track whether it is instantiation/destruction aware if (beanPostProcessor instanceof InstantiationAwareBeanPostProcessor) { this.hasInstantiationAwareBeanPostProcessors = true; } if (beanPostProcessor instanceof DestructionAwareBeanPostProcessor) { this.hasDestructionAwareBeanPostProcessors = true; } // Add to end of list this.beanPostProcessors.add(beanPostProcessor); } // beanPostProcessors如下 private final List<BeanPostProcessor> beanPostProcessors = new CopyOnWriteArrayList<>();
这个ApplicationContextAwareProcessor也很重要，在Bean初始化过程中其invokeAwareInterfaces方法会对bean进行处理，设置一些基础设置、顶层感知器。
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); } }
