Spring是一个非常活跃的开源框架;它是一个基于Core来架构多层JavaEE系统的框架,它的主要目的是简化企业开发。Spring以一种非侵入式的方式来管理你的代码,Spring提倡“最少侵入,这也意味着你可以适当的时候安装或卸载Spring。
1、BeanFactory
2、ApplicationContext
3、Bean创建过程
4、容器扩展
5、感知接口 *Aware
6、广播与监听
7、资源
8、运行环境抽象
BeanFactory类图
![](https://img.laitimes.com/img/__Qf2AjLwojIjJCLyojI0JCLicmbw5iNjFjN5U2MlVzNkV2YmBDMiRDM0QDM4QmY5QDMlRGOw8CX5EzLcJDMxIDMy8CXn9Gbi9CXzV2Zh1WavwVbvNmLvR3YxUjL1M3Lc9CX6MHc0RHaiojIsJye.png)
- BeanFactory - SpringIoC容器顶级接口,定义了对单个bean的获取,对bean的作用域判断,获取bean类型,获取bean别名的功能
AbstractApplicationContext .refresh() 源码脉络
- ApplicationContext - 继承于BeanFactory,包括了BeanFactory的所有功能
AbstractApplicationContext .refresh() 方法
@Overridepublic void refresh() throws BeansException, IllegalStateException { synchronized (this.startupShutdownMonitor) { // Prepare this context for refreshing. prepareRefresh(); // Tell the subclass to refresh the internal bean factory. ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); // Prepare the bean factory for use in this context. 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. finishBeanFactoryInitialization(beanFactory); // Last step: publish corresponding event. 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(); } }}
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prepareRefresh()
为刷新准备上下文,主要设置状态量(是否关闭,是否激活),记录启动时间,初始化属性资源占位符、校验必填属性是否配置及初始化用于存储早期应用事件的容器
- obtainFreshBeanFactory()
主要用于获取一个新的BeanFactory,如果BeanFactory已存在,则将其销毁并重建,默认重建的BeanFactory为AbstractRefreshableApplicationContext;此外此方法委托其子类从XML中或基于注解的类中加载BeanDefinition
- prepareBeanFactory()
配置BeanFactory使其具有一个上下文的标准特征,如上下文的类加载器、后处理程序(post-processors,如设置如总感知接口)
- postprocessBeanFactory()
在应用上下文内部的BeanFactory初始化结束后对其进行修改,在所有的BeanDefinition已被加载但还没有实例化bean, 此刻可以注册一些特殊的BeanPostFactory,如web应用会注册ServletContextAwareProcessor等
- invokeBeanFactoryPostProcessors()
调用注册在上下文中的BeanFactoryPostProcessor,如果有顺序则按顺序调用,并且一定再单列对象实例化之前调用
- registerBeanPostProcessors()
实例化并注册BeanPostProcessor,如果有显式的顺序则按照顺序调用一定在所有bean实例化之前调用
- initMessageSource()
初始化MessageSource,如果当前上下文没有定义则使用其父类的,如果BeanFactory中不能找到名称为messageSource中的bean, 则默认使用DelegatingMessageSource
- initApplicationEventMulticaster()
初始化ApplicationEventMulticaster,如果上下文没有定义则默认使用SimpleApplicationEventMulticaster,此类主要用于广播ApplicationEvent
- onRefresh()
在一些特定的上下文子类中初始化特定的bean,如在Webapp的上下文中初始化主题资源
- registerListeners()
添加实现了ApplicationListener的bean作为监听器,它不影响非bean的监听器;还会使用多播器发布早期的ApplicationEvent
- finishBeanFactoryInitialization()
实例化所有非延迟加载的单例,完成BeanFactory的初始化工作
- finishRefresh()
完成上下文的刷新工作,调用LifecycleProcessor的onFresh()及发布的ContextRefreshEvent事件
- resetCommonCaches()