obtainFreshBeanFactory()

方法内容：

protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
        refreshBeanFactory();
        ConfigurableListableBeanFactory beanFactory = getBeanFactory();
        if (logger.isDebugEnabled()) {
            logger.debug("Bean factory for " + getDisplayName() + ": " + beanFactory);
        }
        return beanFactory;
    }

实现一：org.springframework.context.support.AbstractRefreshableApplicationContext.class

refreshBeanFactor()代码

@Override
    protected final void refreshBeanFactory() throws BeansException {
        //如果有beanFactory先销毁
        if (hasBeanFactory()) {
            destroyBeans();
            closeBeanFactory();
        }
        try {
            DefaultListableBeanFactory beanFactory = createBeanFactory();//创建新工厂
            beanFactory.setSerializationId(getId());//设置serializationId
            customizeBeanFactory(beanFactory);//设置beanFactory
            loadBeanDefinitions(beanFactory);//加载BeanDefinitions
            synchronized (this.beanFactoryMonitor) {
                this.beanFactory = beanFactory;
            }
        }
        catch (IOException ex) {
            throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex);
        }
    }

1、先销毁原有beanFactory;
2、创建并初始化BeanFactory；
3、加载BeanDefinitions。

实现二：org.springframework.context.support.GenericApplicationContext.class

refreshBeanFactor()代码

@Override
    protected final void refreshBeanFactory() throws IllegalStateException {
        if (!this.refreshed.compareAndSet(false, true)) {
            throw new IllegalStateException(
                    "GenericApplicationContext does not support multiple refresh attempts: just call 'refresh' once");
        }
        this.beanFactory.setSerializationId(getId());
    }

仅设置beanFactory的serializationId；

那么，这个beanFactory是在什么时候实例化的？beanDefinitions是在什么地方加载的？

beanFactory实例化：
beanFactory是在GenericApplicationContext的默认构造函数里实例化的（DefaultListableBeanFactory）

加载beanDefinitions：
GenericApplicationContext的子类在构造函数里加载beanDefinitions