spring 中AbstractApplicationContext的refresh方法

	@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.
			//解析xml 配置中的各个标签并且封装成BeanDefinition
			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) {
				// Destroy already created singletons to avoid dangling resources.
				destroyBeans();

				// Reset 'active' flag.
				cancelRefresh(ex);

				// Propagate exception to caller.
				throw ex;
			}
		}
	}

obtainFreshBeanFactory

refreshBeanFactory

obtainFreshBeanFactory中最主要的方法其实是refreshBeanFactory

protected final void refreshBeanFactory() throws BeansException {
		if (hasBeanFactory()) {
			destroyBeans();
			closeBeanFactory();
		}
		try {
		//这个方法会看看parent 里面有没有beanFactory 所以new 了一个新的DefaultListableBeanFactory 
			DefaultListableBeanFactory beanFactory = createBeanFactory();
			beanFactory.setSerializationId(getId());
			customizeBeanFactory(beanFactory);
			loadBeanDefinitions(beanFactory);
			synchronized (this.beanFactoryMonitor) {
				this.beanFactory = beanFactory;
			}
		}
		catch (IOException ex) {
			throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex);
		}
	}

loadBeanDefinitions

protected void loadBeanDefinitions(DefaultListableBeanFactory beanFactory) throws BeansException, IOException {
		// Create a new XmlBeanDefinitionReader for the given BeanFactory.
		XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader(beanFactory);

		// Configure the bean definition reader with this context's
		// resource loading environment.
		//环境 例如生产环境，开发环境等
		beanDefinitionReader.setEnvironment(getEnvironment());
		beanDefinitionReader.setResourceLoader(this);
		// 解析规则 .xsd 文件 dtd ,
		// 进下面的类看到以下的东西
		//public static final String DEFAULT_SCHEMA_MAPPINGS_LOCATION = "META-INF/spring.schemas";
·		//	public static final String XSD_SUFFIX = ".xsd";为什么要去META-INF/spring.schemas配置很清楚了
		beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this));

		// Allow a subclass to provide custom initialization of the reader,
		// then proceed with actually loading the bean definitions.
		initBeanDefinitionReader(beanDefinitionReader);
		loadBeanDefinitions(beanDefinitionReader);
	}

protected void loadBeanDefinitions(XmlBeanDefinitionReader reader) throws IOException {
//如果不填写的话，并且没有ServeltName默认是
//public static final String DEFAULT_CONFIG_LOCATION = "/WEB-INF/applicationContext.xml";

		String[] configLocations = getConfigLocations();
		if (configLocations != null) {
			for (String configLocation : configLocations) {
				reader.loadBeanDefinitions(configLocation);
			}
		}
	}

此处设置了ConfigLocation

public static final String CONFIG_LOCATION_PARAM = "contextConfigLocation";
	String configLocationParam = sc.getInitParameter(CONFIG_LOCATION_PARAM);
		if (configLocationParam != null) {
			wac.setConfigLocation(configLocationParam);
		}

解析标签

//最终的解析标签在这

	protected void parseBeanDefinitions(Element root, BeanDefinitionParserDelegate delegate) {
		if (delegate.isDefaultNamespace(root)) {
			NodeList nl = root.getChildNodes();
			for (int i = 0; i < nl.getLength(); i++) {
				Node node = nl.item(i);
				if (node instanceof Element) {
					Element ele = (Element) node;
					if (delegate.isDefaultNamespace(ele)) {
					//解析默的标签 有bean beans import alias 4个 ，很简单不去看了
						parseDefaultElement(ele, delegate);
					}
					else {
					//这个解析的是自定义标签
						delegate.parseCustomElement(ele);
					}
				}
			}
		}
		else {
			delegate.parseCustomElement(root);
		}
	}

解析自定义标签

public BeanDefinition parseCustomElement(Element ele, BeanDefinition containingBd) {
//获取元素的uri
		String namespaceUri = getNamespaceURI(ele);
		//根据uri 找到继承NameSpaceHandler的类，见下面的代码
		NamespaceHandler handler = this.readerContext.getNamespaceHandlerResolver().resolve(namespaceUri);
		if (handler == null) {
			error("Unable to locate Spring NamespaceHandler for XML schema namespace [" + namespaceUri + "]", ele);
			return null;
		}
		//开始解析并且封装成BeanDefinition
		return handler.parse(ele, new ParserContext(this.readerContext, this, containingBd));

	}






public NamespaceHandler resolve(String namespaceUri) {
//这边加载所有jar 包包括项目下的META-INF/spring.handlers
//public static final String DEFAULT_HANDLER_MAPPINGS_LOCATION = "META-INF/spring.handlers";这个是证据

		Map handlerMappings = getHandlerMappings();
		// 获取到处理类
		Object handlerOrClassName = handlerMappings.get(namespaceUri);
		if (handlerOrClassName == null) {
			return null;
		}
		else if (handlerOrClassName instanceof NamespaceHandler) {
			return (NamespaceHandler) handlerOrClassName;
		}
		else {
			String className = (String) handlerOrClassName;
			try {
				Class handlerClass = ClassUtils.forName(className, this.classLoader);
				if (!NamespaceHandler.class.isAssignableFrom(handlerClass)) {
					throw new FatalBeanException("Class [" + className + "] for namespace [" + namespaceUri +
							"] does not implement the [" + NamespaceHandler.class.getName() + "] interface");
				}
				NamespaceHandler namespaceHandler = (NamespaceHandler) BeanUtils.instantiateClass(handlerClass);
				// 掉用init 就会注册解析方法
				namespaceHandler.init();
				handlerMappings.put(namespaceUri, namespaceHandler);
				return namespaceHandler;
			}
			catch (ClassNotFoundException ex) {
				throw new FatalBeanException("NamespaceHandler class [" + className + "] for namespace [" +
						namespaceUri + "] not found", ex);
			}
			catch (LinkageError err) {
				throw new FatalBeanException("Invalid NamespaceHandler class [" + className + "] for namespace [" +
						namespaceUri + "]: problem with handler class file or dependent class", err);
			}
		}
	}

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后天写