springboot2.1.7启动 AbstractApplicationContext refresh(一)

目录

 

prepareRefresh()

ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory()

prepareBeanFactory(beanFactory)

postProcessBeanFactory(beanFactory)

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prepareRefresh()

准备此上下文以进行刷新，设置其启动日期和活动标志以及执行属性源的任何初始化。

ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory()

告诉子类刷新内部bean工厂。beanFactory为DefaultListableBeanFactory。

prepareBeanFactory(beanFactory)

配置工厂的标准上下文特征（设置beanFactory的各种属性）

	protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
		// Tell the internal bean factory to use the context's class loader etc.
        //设置类加载器
		beanFactory.setBeanClassLoader(getClassLoader());
        //设置表达式解析器
		beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
        //添加一个PropertyEditorRegistrar以应用于所有bean创建过程。
		beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));

		// Configure the bean factory with context callbacks.
        //处理各种Aware接口的设置
		beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
		beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
		beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
		beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
		beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
		beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
		beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);

		// BeanFactory interface not registered as resolvable type in a plain factory.
		// MessageSource registered (and found for autowiring) as a bean.
		beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
		beanFactory.registerResolvableDependency(ResourceLoader.class, this);
		beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
		beanFactory.registerResolvableDependency(ApplicationContext.class, this);

		// Register early post-processor for detecting inner beans as ApplicationListeners.
		beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));

		// Detect a LoadTimeWeaver and prepare for weaving, if found.
		if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
			beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
			// Set a temporary ClassLoader for type matching.
			beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
		}

		// Register default environment beans.
        //注册默认环境bean
		if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) {
			beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment());
		}
		if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) {
			beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties());
		}
		if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) {
			beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment());
		}
	}

void registerResolvableDependency(Class<?> dependencyType, @Nullable Object autowiredValue):用相应的自动装配值注册一个专用的依赖类型。即当通过dependencyType（class）获取bean时，会获取到autowiredValued对象或其代理对象。下方会用示例说明。

postProcessBeanFactory(beanFactory)

允许在上下文子类中对bean工厂进行后处理。目前注册了一个BeanPostProcessor（WebApplicationContextServletContextAwareProcessor），使用WebApplicationContext所使用的给定BeanFactory注册特定于Web的范围（"request", "session", "globalSession", "application")。该方法也会调用registerResolvableDependency方法，以ServletRequest作为例子简单说明下。

registerResolvableDependency示例：

beanFactory.registerResolvableDependency(ServletRequest.class, new RequestObjectFactory()) ：可以看出ServletRequest对应的bean实例是RequestObjectFactory。下图是@Resource引入的HttpServletRequest依赖实例。

@Resource
private HttpServletRequest httpServletRequest

 从上图可以看出，httpServletRequest是一个动态代理对象。ObjectFactoryDelegatingInvocationHandler（AutowireUtils中的静态内部类）所持有的objectFactory真实对象是RequestObjectFactory（RequestObjectFactory是WebApplicationContextUtils中的静态内部类）。

	private static class ObjectFactoryDelegatingInvocationHandler implements InvocationHandler, Serializable {

		private final ObjectFactory<?> objectFactory;

		public ObjectFactoryDelegatingInvocationHandler(ObjectFactory<?> objectFactory) {
			this.objectFactory = objectFactory;
		}