Spring IOC容器启动过程

IOC容器启动过程

资源定位(classpath,filesystem等)

载入，将bean定义转换为内部数据结构BeanDefintion

向IOC容器注册bean

资源定位

定位配置文件，通过BeadDefinetionReader读入配置

refresh方法实现

IOC容器启动方法是ConfigurableApplicationContext中定义的refresh方法，在AbstractApplicationContext中实现

//准备阶段做的是：标记容器为active状态，以及检查当前的运行环境，比如使用log4j，还是jdklog等
prepareRefresh();

//创建beanfactory， 定位资源，载入，装配beandefinetion
// Tell the subclass to refresh the internal bean factory.
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

//初始化beanfactory, 设置contex的classloader

// Prepare the bean factory for use in this context.
prepareBeanFactory(beanFactory);

try {
//在基本的初始化之后，对beanfactory做一些修改
// Allows post-processing of the bean factory in context subclasses.
postProcessBeanFactory(beanFactory);

//调用beanfactory后处理器
// Invoke factory processors registered as beans in the context.
invokeBeanFactoryPostProcessors(beanFactory);

//注册bean后处理器
// Register bean processors that intercept bean creation.
registerBeanPostProcessors(beanFactory);

//初始化消息资源，国际化
// Initialize message source for this context.
initMessageSource();

// Initialize event multicaster for this context.
initApplicationEventMulticaster();
//在实例化bean之前，做一些工作
// Initialize other special beans in specific context subclasses.
onRefresh();

//注册 ApplicationListener监听器
// Check for listener beans and register them.
registerListeners();

//实例化bean
// Instantiate all remaining (non-lazy-init) singletons.
finishBeanFactoryInitialization(beanFactory);

//发布bean正常响应事件，初始化bean生命周期处理器
// Last step: publish corresponding event.
finishRefresh();
}

BeanDefinetion

BeanDefinetion是定义bean的抽象

向IOC容器注册BeanDefinetion

用HashMap维护BeanDefinetion, beanName作为key,BeanDefintion作为value

如果有同名key，如果有配置overridebean，那就覆盖，没有就报错

populateBean方法完成bean的依赖注入

依赖注入

// Instantiate all remaining (non-lazy-init) singletons.
//在refresh方法中初始化非懒加载的bean
finishBeanFactoryInitialization(beanFactory);