解析并符号 读取dll_Spring IOC容器之XmlBeanFactory启动流程分析和源码解析

@deprecated as of Spring 3.1 in favor of {@link DefaultListableBeanFactory}

ClassPathResource resource=new ClassPathResource("spring-config.xml");
DefaultListableBeanFactory beanFactory=new DefaultListableBeanFactory();
XmlBeanDefinitionReader beanDefinitionReader=new XmlBeanDefinitionReader(beanFactory);
beanDefinitionReader.loadBeanDefinitions(resource);

<?xml version="1.0" encoding=" UTF-8" standalone="yes"?><root>
<code>0</code>
<message>调用成功</message>
</root>

String xml="<?xml version="1.0" encoding=" UTF-8" standalone="yes"?><root>n" +"<code>0</code>n" +"<message>调用成功</message>n" +"</root>";
Document document = DocumentHelper.parseText(xml);
Element root = document.getRootElement();
String code = root.elementText("code");
String message =root.elementText("message");

ClassPathResource resource = new ClassPathResource("spring-config.xml");
XmlBeanFactory beanFactory = new XmlBeanFactory(resource);

/*** XmlBeanFactory**/
public XmlBeanFactory(Resource resource) throws BeansException {this(resource, null);
}public XmlBeanFactory(Resource resource, BeanFactory parentBeanFactory) throws BeansException  {super(parentBeanFactory); // 加载(解析注册)BeanDefinitionthis.reader.loadBeanDefinitions(resource);
}

/*** XmlBeanDefinitionReader**/
public int loadBeanDefinitions(Resource resource) throws BeanDefinitionStoreException {// 把从XML文件读取的Resource资源进行编码处理return loadBeanDefinitions(new EncodedResource(resource));
}/*** XmlBeanDefinitionReader**/
public int loadBeanDefinitions(EncodedResource encodedResource) throws BeanDefinitionStoreException {...// 完成resource->inputStream->inputSource转换，使用SAX方式接收输入源InputSource解析XMLtry (InputStream inputStream = encodedResource.getResource().getInputStream()) {InputSource inputSource = new InputSource(inputStream);if (encodedResource.getEncoding() != null) {inputSource.setEncoding(encodedResource.getEncoding());}// 执行加载BeanDefinitionreturn doLoadBeanDefinitions(inputSource, encodedResource.getResource());}...
}

/*** XmlBeanDefinitionReader**/
protected int doLoadBeanDefinitions(InputSource inputSource, Resource resource)throws BeanDefinitionStoreException {...try {// inputSource->DOM DocumentDocument doc = doLoadDocument(inputSource, resource);int count = registerBeanDefinitions(doc, resource);return count;}...
}

/*** XmlBeanDefinitionReader**/
public int registerBeanDefinitions(Document doc, Resource resource) throws BeanDefinitionStoreException {BeanDefinitionDocumentReader documentReader = createBeanDefinitionDocumentReader();// 已注册的BeanDefinition的数量int countBefore = getRegistry().getBeanDefinitionCount();// DOM Document->BeanDefinition，注册BeanDefinition至容器documentReader.registerBeanDefinitions(doc, createReaderContext(resource));// 返回此次注册新增的BeanDefinition数量return getRegistry().getBeanDefinitionCount() - countBefore;
}

/*** DefaultBeanDefinitionDocumentReader**/
public void registerBeanDefinitions(Document doc, XmlReaderContext readerContext) {this.readerContext = readerContext;doRegisterBeanDefinitions(doc.getDocumentElement());
}

/*** DefaultBeanDefinitionDocumentReader**/
protected void doRegisterBeanDefinitions(Element root) {BeanDefinitionParserDelegate parent = this.delegate;this.delegate = createDelegate(getReaderContext(), root, parent);...// 解析前处理，留给子类实现preProcessXml(root);parseBeanDefinitions(root, this.delegate);// 解析后处理，留给子类实现postProcessXml(root);this.delegate = parent;
}

/*** DefaultBeanDefinitionDocumentReader**/
protected void parseBeanDefinitions(Element root, BeanDefinitionParserDelegate delegate){// 对beans的处理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)) {// 对默认的Bean标签解析parseDefaultElement(ele, delegate);}else {// 对自定义的Bean标签解析delegate.parseCustomElement(ele);}}}}else {delegate.parseCustomElement(root);}
}

/*** DefaultBeanDefinitionDocumentReader**/
private void parseDefaultElement(Element ele, BeanDefinitionParserDelegate delegate) {if (delegate.nodeNameEquals(ele, IMPORT_ELEMENT)) {// import标签importBeanDefinitionResource(ele);}else if (delegate.nodeNameEquals(ele, ALIAS_ELEMENT)) {// alias标签processAliasRegistration(ele);}else if (delegate.nodeNameEquals(ele, BEAN_ELEMENT)) {// bean标签processBeanDefinition(ele, delegate);}else if (delegate.nodeNameEquals(ele, NESTED_BEANS_ELEMENT)) {// beans标签doRegisterBeanDefinitions(ele);}
}

/*** DefaultBeanDefinitionDocumentReader**/
protected void processBeanDefinition(Element ele, BeanDefinitionParserDelegate delegate){BeanDefinitionHolder bdHolder = delegate.parseBeanDefinitionElement(ele); // 参考4.1源码if (bdHolder != null) {bdHolder = delegate.decorateBeanDefinitionIfRequired(ele, bdHolder); // 参考4.2源码try {BeanDefinitionReaderUtils.registerBeanDefinition(bdHolder, getReaderContext().getRegistry()); // 参考5.1源码}...// Send registration event.getReaderContext().fireComponentRegistered(new BeanComponentDefinition(bdHolder));}
}

/*** BeanDefinitionParseDelegate**/
public BeanDefinitionHolder parseBeanDefinitionElement(Element ele) {return parseBeanDefinitionElement(ele, null);
}
/*** BeanDefinitionParseDelegate**/
public BeanDefinitionHolder parseBeanDefinitionElement(Element ele, @Nullable BeanDefinition containingBean) {// 解析id属性String id = ele.getAttribute(ID_ATTRIBUTE);// 解析name属性String nameAttr = ele.getAttribute(NAME_ATTRIBUTE);List<String> aliases = new ArrayList<>();if (StringUtils.hasLength(nameAttr)) {String[] nameArr = StringUtils.tokenizeToStringArray(nameAttr, MULTI_VALUE_ATTRIBUTE_DELIMITERS);aliases.addAll(Arrays.asList(nameArr));}String beanName = id;if (!StringUtils.hasText(beanName) && !aliases.isEmpty()) {beanName = aliases.remove(0);}if (containingBean == null) {checkNameUniqueness(beanName, aliases, ele);}AbstractBeanDefinition beanDefinition = parseBeanDefinitionElement(ele, beanName, containingBean);if (beanDefinition != null) {...String[] aliasesArray = StringUtils.toStringArray(aliases);return new BeanDefinitionHolder(beanDefinition, beanName, aliasesArray);}
} 

/*** BeanDefinitionParseDelegate**/
public BeanDefinitionHolder decorateBeanDefinitionIfRequired(Element ele, BeanDefinitionHolder originalDef, @Nullable BeanDefinition containingBd) {BeanDefinitionHolder finalDefinition = originalDef;// Decorate based on custom attributes first.// 首先对自定义属性解析和装饰NamedNodeMap attributes = ele.getAttributes();for (int i = 0; i < attributes.getLength(); i++) {Node node = attributes.item(i);finalDefinition = decorateIfRequired(node, finalDefinition, containingBd);}// Decorate based on custom nested elements.// 装饰标签下的自定义子节点NodeList children = ele.getChildNodes();for (int i = 0; i < children.getLength(); i++) {Node node = children.item(i);if (node.getNodeType() == Node.ELEMENT_NODE) {finalDefinition = decorateIfRequired(node, finalDefinition, containingBd);}}return finalDefinition;
}

/*** BeanDefinitionReaderUtils**/
public static void registerBeanDefinition(BeanDefinitionHolder definitionHolder, BeanDefinitionRegistry registry)throws BeanDefinitionStoreException {// Register bean definition under primary name.// 使用beanName注册BeanDefinitionString beanName = definitionHolder.getBeanName();registry.registerBeanDefinition(beanName, definitionHolder.getBeanDefinition());// Register aliases for bean name, if any.// 使用别名注册BeanDefiniionString[] aliases = definitionHolder.getAliases();if (aliases != null) {for (String alias : aliases) {registry.registerAlias(beanName, alias);}}
}/*** BeanDefinitionParseDelegate**/
public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)throws BeanDefinitionStoreException {...BeanDefinition existingDefinition = this.beanDefinitionMap.get(beanName);if (existingDefinition != null) {...this.beanDefinitionMap.put(beanName, beanDefinition);}else{if (hasBeanCreationStarted()) {// beanDefinitionMap是全局变量，会存在并发访问问题synchronized (this.beanDefinitionMap) {this.beanDefinitionMap.put(beanName, beanDefinition);List<String> updatedDefinitions = new ArrayList<>(this.beanDefinitionNames.size() + 1);updatedDefinitions.addAll(this.beanDefinitionNames);updatedDefinitions.add(beanName);this.beanDefinitionNames = updatedDefinitions;removeManualSingletonName(beanName);}}else {// Still in startup registration phasethis.beanDefinitionMap.put(beanName, beanDefinition);this.beanDefinitionNames.add(beanName);removeManualSingletonName(beanName);}this.frozenBeanDefinitionNames = null;}...
}