Spring IOC 源码-ClassPathXmlApplicationContext-bean解析

1、使用方式-使用ApplicationContext方式加载XML

@Test

    public void testBeanLoader(){

        BeanFactory bf = new ClassPathXmlApplicationContext("configuration/spring-test.xml");

}

2、解析ClassPathXmlApplicationContext构造函数：

public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh, ApplicationContext parent)

            throws BeansException {

 

        super(parent);

        setConfigLocations(configLocations);//设置配置文件信息

        if (refresh) {

            refresh();//主要的加载bean的过程

        }

    }

3、refresh方法：

@Override

    public void refresh() throws BeansException, IllegalStateException {

        synchronized (this.startupShutdownMonitor) {

            // 准备刷新上下文环境

            prepareRefresh();

 

            // 初始化beanFactory并进行xml文件的读取

            ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

 

            //对beanfactory进行功能填充

            prepareBeanFactory(beanFactory);

 

            try {

                // Allows post-processing of the bean factory in context subclasses.

                postProcessBeanFactory(beanFactory); //允许beanfactory在上下环境中对子类的后处理

 

                // Invoke factory processors registered as beans in the context.

                invokeBeanFactoryPostProcessors(beanFactory); //激活beanfactory

 

                // Register bean processors that intercept bean creation.

                registerBeanPostProcessors(beanFactory); //注册bean后处理，此时注册的并不是真正的bean，真正的bean是通过getBean得到的

 

                // Initialize message source for this context.

                initMessageSource(); //为上下文初始化message源

 

                // Initialize event multicaster for this context.

                initApplicationEventMulticaster(); //初始化应用消息广播器并注册到ApplicationEventMulticaster中

 

                // Initialize other special beans in specific context subclasses.

                onRefresh(); //初始化其他上下文中子类中的特殊bean

 

                // Check for listener beans and register them.

                registerListeners(); //查找lestenerbean，并注册到消息广播器中

 

                // Instantiate all remaining (non-lazy-init) singletons.

                finishBeanFactoryInitialization(beanFactory); //初始化单例

 

                // Last step: publish corresponding event.

                finishRefresh(); //初始化完成

            }

 

            catch (BeansException ex) {

                logger.warn("Exception encountered during context initialization - cancelling refresh attempt", ex);

 

                // Destroy already created singletons to avoid dangling resources.

                destroyBeans(); //异常时销毁bean

 

                // 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();

            }

        }

    }