Spring容器(三)：prepare BeanFactory

在BeanFactory的准备阶段，会调用下面几个方法：

• prepareRefresh();
• ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
• prepareBeanFactory(beanFactory);
• postProcessBeanFactory(beanFactory);

1. prepareRefresh()

protected void prepareRefresh() {
        //初始化属性设置；子类可以自定义自己的属性
        initPropertySources();
        //属性校验
        getEnvironment().validateRequiredProperties();
        this.earlyApplicationEvents = new LinkedHashSet<ApplicationEvent>();
    }

2. obtainFreshBeanFactory()

    protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
        //为上文中创建好的DefaultListableBeanFactory设置SerializationId
        refreshBeanFactory();
        //返回创建的BeanFactory
        ConfigurableListableBeanFactory beanFactory = getBeanFactory();
        if (logger.isDebugEnabled()) {
            logger.debug("Bean factory for " + getDisplayName() + ": " + beanFactory);
        }
        return beanFactory;
    }

3. prepareBeanFactory(beanFactory)：给beanFactory设置一些属性：环境、系统属性

protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
       // Tell the internal bean factory to use the context's class loader etc.
       beanFactory.setBeanClassLoader(getClassLoader());
       beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
       beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));

       // Configure the bean factory with context callbacks.
       beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
       //注册忽略自动装配的组件 
       beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
       beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
       beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
       beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
       beanFactory.ignoreDependencyInterface(EnvironmentAware.class);

       // BeanFactory interface not registered as resolvable type in a plain factory.
       // MessageSource registered (and found for autowiring) as a bean.
       beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
       beanFactory.registerResolvableDependency(ResourceLoader.class, this);
       beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
       beanFactory.registerResolvableDependency(ApplicationContext.class, this);

       // Detect a LoadTimeWeaver and prepare for weaving, if found.
       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.
       if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) {
           beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment());
       }
       if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) {
           beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties());
       }
       if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) {
           beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment());
       }
   }

4. postProcessBeanFactory(beanFactory)

子类可以通过重写这个方法，在BeanFactory准备完成阶段做进一步的设置