spring源码学习（八）容器功能拓展

我们在项目上常用的一般是ClassPathXmlApplicationContext这个类.

    public ClassPathXmlApplicationContext(
            String[] configLocations, boolean refresh, @Nullable ApplicationContext parent)
            throws BeansException {

        super(parent);
        setConfigLocations(configLocations);
        if (refresh) {
            refresh();
        }
    }

    public void setConfigLocations(@Nullable String... locations) {
        if (locations != null) {
            Assert.noNullElements(locations, "Config locations must not be null");
            this.configLocations = new String[locations.length];
            for (int i = 0; i < locations.length; i++) {
                this.configLocations[i] = resolvePath(locations[i]).trim();
            }
        }
        else {
            this.configLocations = null;
        }
    }

    @Override
    public void refresh() throws BeansException, IllegalStateException {
        synchronized (this.startupShutdownMonitor) {
            // Prepare this context for refreshing.
            //准备刷新的上下文环境
            prepareRefresh();

            // Tell the subclass to refresh the internal bean factory.
            //初始化BeanFactory，进行Xml文件获取
            ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

            // Prepare the bean factory for use in this context.
            //对BeanFactory进行各种功能填充
            prepareBeanFactory(beanFactory);

            try {
                // Allows post-processing of the bean factory in context subclasses.
                //子类覆盖方法做额外处理
                postProcessBeanFactory(beanFactory);

                // Invoke factory processors registered as beans in the context.
                //**各种BeanFactory处理器
                invokeBeanFactoryPostProcessors(beanFactory);

                // Register bean processors that intercept bean creation.
                //注册拦截Bean创建的Bean处理器，这里只是注册，真正的调用在getBean
                registerBeanPostProcessors(beanFactory);

                // Initialize message source for this context.
                //为上下文初始化Message源，即国际化
                initMessageSource();

                // Initialize event multicaster for this context.
                //初始化应用消息广播器
                initApplicationEventMulticaster();

                // Initialize other special beans in specific context subclasses.
                //留给子类来初始化其他的Bean
                onRefresh();

                // Check for listener beans and register them.
                //在所有注册的bean中查找Listener bran
                registerListeners();

                // Instantiate all remaining (non-lazy-init) singletons.
                //初始化剩下的单实例
                finishBeanFactoryInitialization(beanFactory);

                // Last step: publish corresponding event.
                //完成刷新过程，通知生命周期处理器lifecycleProcessor刷新
                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();
            }
        }
    }

在ClassPathXmlApplicationContext中，做了很多功能上的拓展，增加了spel语言支持，增加了属性注册编辑器，添加了ApplicationContext AwreProcessor处理器，设置依赖忽略和注册依赖，BeanFactory的后处理等，但是核心的东西依然和XmlBeanFactory中相同，所以就不在深入查看源代码了，之后会看一下spring AOP的源码，以后有时间的话会在重新把这里的源码补全。