spring加载配置文件,AbstractApplicationContext类中的refresh方法起着重要的作用。
@Override public void refresh() throws BeansException, IllegalStateException { synchronized (this.startupShutdownMonitor) { // Prepare this context for refreshing.准备刷新context prepareRefresh(); // Tell the subclass to refresh the internal bean factory.刷新子类beanFactory,注册beanDefinition ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); // Prepare the bean factory for use in this context.准备beanfactory prepareBeanFactory(beanFactory); try { // Allows post-processing of the bean factory in context subclasses. postProcessBeanFactory(beanFactory); // Invoke factory processors registered as beans in the context. invokeBeanFactoryPostProcessors(beanFactory); // Register bean processors that intercept bean creation. registerBeanPostProcessors(beanFactory); // Initialize message source for this context. initMessageSource(); // Initialize event multicaster for this context. initApplicationEventMulticaster(); // Initialize other special beans in specific context subclasses. onRefresh(); // Check for listener beans and register them. registerListeners(); // Instantiate all remaining (non-lazy-init) singletons.初始化非懒加载的bean实例 finishBeanFactoryInitialization(beanFactory); // Last step: publish corresponding event. finishRefresh(); } catch (BeansException ex) { 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; } } }
实例化bean对象,主要的是在
finishBeanFactoryInitialization(beanFactory)
方法。
大致的流程图(下部分):
(点击查看大图)
下面分析实例化bean对象的源码分析
加载bean对象:
在AbstractBeanFactory类中,根据不同scope进行实例化,例如Singleton,Prototype等
根据不同情况采用不同的代理方式:
到这里就是bean实例的初始化,可以看到spring采用的代理方式,来实现bean的初始化。