前面两篇分别讲了Spring初始化容器的时候XML配置方式和注解方式如何解析注册BeanDefinition的整个过程。Spring在初始化 ApplicationContext容器的过程中注册BeanDefinition只是其中的一个步骤，其中还有很多处理比如初始化国际化资源、应用事件广播、应用事件监听等都是在抽象类AbstractApplicationContext的refresh()方法中完成的。
下面是整个refresh()方法的流程
1.prepareRefresh()：容器刷新前的准备，设置了开始时间、状态、验证所有标记为必需的属性是否可解析和一个模板方法initPropertySources()。
2.obtainFreshBeanFactory()：里面两个模板方法refreshBeanFactory()和getBeanFactory()。看过之前xml配置方式注册BeanDefinition的应该知道入口就是AbstractRefreshableApplicationContext的refreshBeanFactory()。getBeanFactory()返回子类创建的bean factory实例，AbstractApplicationContext中不存在BeanFactory的实例，所以提供模板方法由子类具体创建提供。
3.prepareBeanFactory(beanFactory)：容器使用前对bean工厂进行一些处理属性设置。
4.postProcessBeanFactory(beanFactory)：模板方法提供给子类对bean工厂进行一些处理。
5.invokeBeanFactoryPostProcessors(beanFactory)：这是一个重点，也是一个扩展点，同时用java做配置时的扫描注册BeanDefinition的入口也在这里。
首先初始化类型为BeanDefinitionRegistryPostProcessors并且实现了接口PriorityOrdered(高优先级)的bean并执行postProcessBeanDefinitionRegistry方法，ConfigurationClassPostProcessor就是在这里执行然后调用doscan方法扫描注册bean定义。
// Do not initialize FactoryBeans here: We need to leave all regular beans
// uninitialized to let the bean factory post-processors apply to them!
// Separate between BeanDefinitionRegistryPostProcessors that implement
// PriorityOrdered, Ordered, and the rest.
List currentRegistryProcessors = new ArrayList<>();
// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
复制代码 然后就是实例化实现了Ordered(排序接口)的BeanDefinitionRegistryPostProcessors实例并调用postProcessBeanDefinitionRegistry方法
// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
复制代码最后实例化没有实现排序接口的BeanDefinitionRegistryPostProcessors实例并调用postProcessBeanDefinitionRegistry方法。 后面是实例实例化实现了BeanFactoryPostProcessor接口的bean并调用postProcessBeanFactory方法，调用顺序和BeanDefinitionRegistryPostProcessors一样。
在这里我们可以插入自己的实现，通过实现BeanDefinitionRegistryPostProcessors接口对bean定义做一些处理，实现BeanFactoryPostProcessor接口可以对bean工厂做一些处理工作。
6.registerBeanPostProcessors(beanFactory)：这也是一个扩展点，在这里会提前初始化所有实现了BeanPostProcessor接口的bean，但不会执行里面的方法。BeanPostProcessor 实例 在getBean()之前和之后可以做一些处理，AOP就是基于BeanPostProcessor实现的。 下面是源码实现
public static void registerBeanPostProcessors(
ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);
// Register BeanPostProcessorChecker that logs an info message when
// a bean is created during BeanPostProcessor instantiation, i.e. when
// a bean is not eligible for getting processed by all BeanPostProcessors.
int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));
// Separate between BeanPostProcessors that implement PriorityOrdered,
// Ordered, and the rest.
List priorityOrderedPostProcessors = new ArrayList<>();
List internalPostProcessors = new ArrayList<>();
List orderedPostProcessorNames = new ArrayList<>();
List nonOrderedPostProcessorNames = new ArrayList<>();
for (String ppName : postProcessorNames) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
priorityOrderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessorNames.add(ppName);
}
else {
nonOrderedPostProcessorNames.add(ppName);
}
}
// First, register the BeanPostProcessors that implement PriorityOrdered.
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);
// Next, register the BeanPostProcessors that implement Ordered.
List orderedPostProcessors = new ArrayList<>();
for (String ppName : orderedPostProcessorNames) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
orderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
sortPostProcessors(orderedPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, orderedPostProcessors);
// Now, register all regular BeanPostProcessors.
List nonOrderedPostProcessors = new ArrayList<>();
for (String ppName : nonOrderedPostProcessorNames) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
nonOrderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);
// Finally, re-register all internal BeanPostProcessors.
sortPostProcessors(internalPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, internalPostProcessors);
// Re-register post-processor for detecting inner beans as ApplicationListeners,
// moving it to the end of the processor chain (for picking up proxies etc).
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}
复制代码 处理逻辑跟上面的BeanFactoryPostProcessor差不多，都是先PriorityOrdered，然后Ordered，最后是普通的实现。
7.initMessageSource()：初始化国际化资源。
8.initApplicationEventMulticaster()：初始化事件广播。
9.onRefresh();模板方法。
10.registerListeners():注册事件监听
11.finishBeanFactoryInitialization(beanFactory)：初始化所有不是懒加载的单例bean。
12.finishRefresh()：完成初始化之后的工作。
整个流程中最主要的其实就是步骤2、5、6和11。分别是xml配置加载Bean定义；初始化实现了BeanFactoryPostProcessor接口的实例，并执行对应的方法；初始化实现了BeanPostProcessor接口的实例；初始化所有非懒加载的单例bean。其他代码感兴趣的可以自己去了解，这里不做过多分析。