Spring源码-05-容器refresh
一 refresh
// AbstractApplicationContext.java
@Override
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
StartupStep contextRefresh = this.applicationStartup.start("spring.context.refresh");
// Prepare this context for refreshing.
/**
* 1 容器启动前置准备
*/
this.prepareRefresh();
// Tell the subclass to refresh the internal bean factory.
/**
* 模板方法
* 从子类的实现(GenericApplicationContext)获取Bean工厂beanFactory(DefaultListableBeanFactory)
*/
ConfigurableListableBeanFactory beanFactory = this.obtainFreshBeanFactory();
// Prepare the bean factory for use in this context.
/**
* 2 Bean工厂前置准备
*/
this.prepareBeanFactory(beanFactory);
try {
// Allows post-processing of the bean factory in context subclasses.
/**
* 3 空实现
*/
this.postProcessBeanFactory(beanFactory);
StartupStep beanPostProcess = this.applicationStartup.start("spring.context.beans.post-process");
// Invoke factory processors registered as beans in the context.
/**
* 4 调用所有注册的BeanFactoryPostProcessor的实例
* - BeanFactoryPostProcessor
* - BeanDefinitionRegistryPostProcessor
* Bean工厂后置处理器职责
* - 作用对象是Bean工厂
* - 现在还没有将用户BeanDefinition注册到Bean工厂中
* - 特定的后置处理器作用是将用户BeanDefinition注册Bean工厂中
* ConfigurationClassPostProcessor作用的时机
* - 解析配置类
* - 注册BeanDefinition到Bean工厂
* - 增强full型配置类
* - 向Bean工厂注册一个Bean后置处理器ImportAwareBeanPostProcessor
*/
this.invokeBeanFactoryPostProcessors(beanFactory);
// Register bean processors that intercept bean creation.
/**
* 5 Bean实例化初始化之前将后置处理器注册到容器中
* 后置处理器的职责
* - BeanDefinition都已经注册到了Bean工厂中(DefaultListableBeanFactory的beanDefinitionMap)
* - Spring可以根据BeanDefinition进行Bean的实例化和初始化
* - 在此之前注册Bean的后置处理器
* - 在Bean实例化前后回调
* - 在Bean初始化前后回调
* 上面Bean工厂后置处理器执行结束之后 就已经将BeanDefinition都注册到Bean工厂beanDefinitionMap中了
* 现在将所有Bean工厂中BeanDefinition中是Bean后置处理器的都进行实例化注册到Bean工厂的beanPostProcessors中
*/
registerBeanPostProcessors(beanFactory);
beanPostProcess.end();
// Initialize message source for this context.
/**
* 6 初始化信息源
* - 国际化
*/
initMessageSource();
// Initialize event multicaster for this context.
/**
* 7 初始化容器事件传播器
*/
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
/**
* 8 特定上下文子类中初始化特殊的Bean
*/
onRefresh();
// Check for listener beans and register them.
/**
* 9 监听器Bean
*/
registerListeners();
// Instantiate all remaining (non-lazy-init) singletons.
/**
* 10 实例化非延迟初始化单例
*/
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.
/**
* 11 初始化容器生命周期事件处理器 发布容器生命周期事件
*/
finishRefresh();
}
catch (BeansException ex) {
if (logger.isWarnEnabled()) {
logger.warn("Exception encountered during context initialization - " +
"cancelling refresh attempt: " + ex);
}
// Destroy already created singletons to avoid dangling resources.
destroyBeans();
// Reset 'active' flag.
cancelRefresh(ex);
// Propagate exception to caller.
throw ex;
}
finally {
// Reset common introspection caches in Spring's core, since we
// might not ever need metadata for singleton beans anymore...
resetCommonCaches();
contextRefresh.end();
}
}
}
二 步骤
三 示意图
![](https://raw.githubusercontent.com/Bannirui/blogs/master/img/202212091645950.png)