@Override
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// 放入容器环境上下文中一些信息主要是 active设置为true、closed设置为false、注入properties中的信息.
prepareRefresh();
// 告诉子类获取内部bean工厂(ConfigurableListableBeanFactory )
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// 将容器环境上下文中的信息注册到factory中
prepareBeanFactory(beanFactory);
try {
// 允许在上下文子类中对bean工厂进行后处理。
postProcessBeanFactory(beanFactory);
// 调用在上下文中注册为bean的工厂处理器
invokeBeanFactoryPostProcessors(beanFactory);
// 注册拦截bean创建的bean处理器。
registerBeanPostProcessors(beanFactory);
// 初始化messageSource
initMessageSource();
// 为此上下文初始化事件Multicaster
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
onRefresh();
// 将监听事件添加到Multicaster
registerListeners();
// 初始化beanfactory (non-lazy-init) singletons.
finishBeanFactoryInitialization(beanFactory);
// 最后,发布对应的事件
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();
}
}
}
}
放到set中
public class DefaultSingletonBeanRegistry extends SimpleAliasRegistry implements SingletonBeanRegistry {
private final Map<String, Object> singletonObjects = new ConcurrentHashMap<>(256);
@Nullable
protected Object getSingleton(String beanName, boolean allowEarlyReference) {
Object singletonObject = this.singletonObjects.get(beanName);
if (singletonObject == null && isSingletonCurrentlyInCreation(beanName)) {
synchronized (this.singletonObjects) {
singletonObject = this.earlySingletonObjects.get(beanName);
if (singletonObject == null && allowEarlyReference) {
ObjectFactory<?> singletonFactory = this.singletonFactories.get(beanName);
if (singletonFactory != null) {
singletonObject = singletonFactory.getObject();
this.earlySingletonObjects.put(beanName, singletonObject);
this.singletonFactories.remove(beanName);
}
}
}
}
return singletonObject;
}
}