Spring源码：Spring IoC容器加载过程（1）

Spring源码版本：4.3.23.RELEASE

一、加载过程概览

Spring容器加载过程可以在org.springframework.context.support.AbstractApplicationContext#refresh方法看到总体过程，具体细节需要断点调试：

     @Override
     public 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();
             }
         }
     }

后续文章根据以上标出来的每一个加载步骤进行解析。