XmlBeanFactory.classpublic class XmlBeanFactory extends DefaultListableBeanFactory {private final XmlBeanDefinitionReader reader;public XmlBeanFactory(Resource resource) throws BeansException {this(resource, (BeanFactory)null);}public XmlBeanFactory(Resource resource, BeanFactory parentBeanFactory) throws BeansException {super(parentBeanFactory);this.reader = new XmlBeanDefinitionReader(this);this.reader.loadBeanDefinitions(resource);}
}

public int loadBeanDefinitions(Resource resource) throws BeanDefinitionStoreException {    return this.loadBeanDefinitions(new EncodedResource(resource));}

public int loadBeanDefinitions(EncodedResource encodedResource){....　　　　InputSource inputSource = new InputSource(inputStream);//通过SAX方式解析XML文件....　　this.doLoadBeanDefinitions(inputSource, encodedResource.getResource());

}

Resource implements InputStreamResource

protected int doLoadBeanDefinitions(InputSource inputSource, Resource resource) throws BeanDefinitionStoreException {try {int validationMode = this.getValidationModeForResource(resource);//获取xml文件的验证模式
            Document doc = this.documentLoader.loadDocument(inputSource, this.getEntityResolver(), this.errorHandler, validationMode, this.isNamespaceAware());//加载XML文件return this.registerBeanDefinitions(doc, resource);//返回注册bean的信息} catch (BeanDefinitionStoreException var5) {throw var5;} catch (SAXParseException var6) {throw new XmlBeanDefinitionStoreException(resource.getDescription(), "Line " + var6.getLineNumber() + " in XML document from " + resource + " is invalid", var6);} catch (SAXException var7) {throw new XmlBeanDefinitionStoreException(resource.getDescription(), "XML document from " + resource + " is invalid", var7);} catch (ParserConfigurationException var8) {throw new BeanDefinitionStoreException(resource.getDescription(), "Parser configuration exception parsing XML from " + resource, var8);} catch (IOException var9) {throw new BeanDefinitionStoreException(resource.getDescription(), "IOException parsing XML document from " + resource, var9);} catch (Throwable var10) {throw new BeanDefinitionStoreException(resource.getDescription(), "Unexpected exception parsing XML document from " + resource, var10);}}

getValidationModeForResource(resource);

protected int getValidationModeForResource(Resource resource) {    int validationModeToUse = this.getValidationMode();    if (validationModeToUse != 1) {        return validationModeToUse;    } else {　　　　　　//如果没有设定模式则进行自动检测模式        int detectedMode = this.detectValidationMode(resource);        return detectedMode != 1 ? detectedMode : 3;    }}

protected int detectValidationMode(Resource resource) {if (resource.isOpen()) {throw new BeanDefinitionStoreException("Passed-in Resource [" + resource + "] contains an open stream: " + "cannot determine validation mode automatically. Either pass in a Resource " + "that is able to create fresh streams, or explicitly specify the validationMode " + "on your XmlBeanDefinitionReader instance.");} else {InputStream inputStream;try {inputStream = resource.getInputStream();} catch (IOException var5) {throw new BeanDefinitionStoreException("Unable to determine validation mode for [" + resource + "]: cannot open InputStream. " + "Did you attempt to load directly from a SAX InputSource without specifying the " + "validationMode on your XmlBeanDefinitionReader instance?", var5);}try {　　　　　　　　　　//将自动检测模式委托给了XmlValidationModeDetector类　　　　　　　　　　　return this.validationModeDetector.detectValidationMode(inputStream); 　　　　　　　} catch (IOException var4) { 　　　　　　　　　　throw new BeanDefinitionStoreException("Unable to determine validation mode for [" + resource + "]: an error occurred whilst reading from the InputStream.", var4); 　　　　　　　} 　　　　　} 　　}

public interface EntityResolver {public abstract InputSource resolveEntity (String publicId,String systemId)throws SAXException, IOException;}

public int registerBeanDefinitions(Document doc, Resource resource) throws BeanDefinitionStoreException {　　　　　　//单一职责原则BeanDefinitionDocumentReader documentReader = this.createBeanDefinitionDocumentReader();documentReader.setEnvironment(this.getEnvironment());int countBefore = this.getRegistry().getBeanDefinitionCount();　　　　　　//加载及注册beandocumentReader.registerBeanDefinitions(doc, this.createReaderContext(resource));return this.getRegistry().getBeanDefinitionCount() - countBefore;}

public void registerBeanDefinitions(Document doc, XmlReaderContext readerContext) {this.readerContext = readerContext;this.logger.debug("Loading bean definitions");Element root = doc.getDocumentElement();this.doRegisterBeanDefinitions(root);}

解析并注册BeanDefinitionsprotected void doRegisterBeanDefinitions(Element root) {String profileSpec = root.getAttribute("profile");if (StringUtils.hasText(profileSpec)) {Assert.state(this.environment != null, "Environment must be set for evaluating profiles");String[] specifiedProfiles = StringUtils.tokenizeToStringArray(profileSpec, ",; ");if (!this.environment.acceptsProfiles(specifiedProfiles)) {return;}}BeanDefinitionParserDelegate parent = this.delegate;this.delegate = this.createHelper(this.readerContext, root, parent);this.preProcessXml(root);//模板方法模式this.parseBeanDefinitions(root, this.delegate);this.postProcessXml(root);this.delegate = parent;}

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)) {this.parseDefaultElement(ele, delegate);//处理默认Bean声明} else {delegate.parseCustomElement(ele);//处理自定义Bean声明}}}} else {delegate.parseCustomElement(root);}}