以下是Spring加载Xml，封装BeanDefiniton的概要代码
主要有这些类
*XmlBeanDefinitionReader
*DefaultBeanDefinitionDocumentReader
*BeanDefinitionParserDelegate
1)[AbstractApplicationContext] ConfigurableListableBeanFactory obtainFreshBeanFactory()
refreshBeanFactory();
2) [AbstractRefreshableApplicationContext] refreshBeanFactory()
DefaultListableBeanFactory beanFactory=new DefaultListableBeanFactory()
loadBeanDefinitions(beanFactory);
3)[AbstractXmlApplicationContext] loadBeanDefinitions(DefaultListableBeanFactory beanFactory)
XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader(beanFactory);
beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this));
loadBeanDefinitions(beanDefinitionReader);
4)[AbstractXmlApplicationContext] loadBeanDefinitions(XmlBeanDefinitionReader reader)
String[] configLocations = getConfigLocations();
reader.loadBeanDefinitions(configLocations);
5)[AbstractBeanDefinitionReader] loadBeanDefinitions(String... locations)
for (String location : locations) {counter += loadBeanDefinitions(location);}
6)[XmlBeanDefinitionReader] doLoadBeanDefinitions(InputSource inputSource, Resource resource)
Document doc = this.documentLoader.loadDocument(inputSource, getEntityResolver(), this.errorHandler, validationMode, isNamespaceAware());
return registerBeanDefinitions(doc, resource); ->
[DefaultDocumentLoader] Document loadDocument(InputSource inputSource, EntityResolver entityResolver,ErrorHandler errorHandler, int validationMode, boolean namespaceAware)
javax.xml.parsers.DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder docBuilder = factory.newDocumentBuilder(); docBuilder.setEntityResolver(entityResolver); return docBuilder.parse(inputSource);
7)[XmlBeanDefinitionReader] registerBeanDefinitions(doc, resource);
BeanDefinitionDocumentReader documentReader = createBeanDefinitionDocumentReader();[DefaultBeanDefinitionDocumentReader]
documentReader.registerBeanDefinitions(doc, createReaderContext(resource));
8)[XmlBeanDefinitionReader] XmlReaderContext createReaderContext(Resource resource)
namespaceHandlerResolver=new DefaultNamespaceHandlerResolver(getResourceLoader().getClassLoader());
return new XmlReaderContext(resource, this.problemReporter, this.eventListener,this.sourceExtractor, this, this.namespaceHandlerResolver);
9)[DefaultBeanDefinitionDocumentReader] registerBeanDefinitions(doc,readerContext)
Element root = doc.getDocumentElement();
doRegisterBeanDefinitions(root);
10)[DefaultBeanDefinitionDocumentReader] doRegisterBeanDefinitions(root)
BeanDefinitionParserDelegate delegate = new BeanDefinitionParserDelegate(readerContext, environment); parseBeanDefinitions(root, this.delegate);
11)[DefaultBeanDefinitionDocumentReader] parseBeanDefinitions(rElement root, BeanDefinitionParserDelegate delegate)
NodeList nl = root.getChildNodes();
for (int i = 0; i < nl.getLength(); i++) {Node node = nl.item(i);Element ele = (Element) node;
if (delegate.isDefaultNamespace(ele)) {parseDefaultElement(ele, delegate);}
else {delegate.parseCustomElement(ele);} }
[return "http://www.springframework.org/schema/beans".equals(node.getNamespaceURI());]
12)[DefaultBeanDefinitionDocumentReader]parseDefaultElement(ele, delegate)
if (delegate.nodeNameEquals(ele, "import")) {importBeanDefinitionResource(ele);}
else if (delegate.nodeNameEquals(ele, "bean")) {processBeanDefinition(ele, delegate);}