spring源码的xml解析过程1（默认标签和自定义标签解析）

源码分析目录

1. spring源码的xml解析过程
2. annotation的支持
3. spring中的实例化以及ioc的过程
4. handlermapping和handlerAdapter请求响应过程
5. 视图解析
6. aop以及事物管理

spring源码的xml解析过程

从 DispatcherServlet 类开始看。
org.springframework.web.servlet.HttpServletBean#init

initServletBean()


org.springframework.web.servlet.FrameworkServlet#initServletBean

this.webApplicationContext &＃61; initWebApplicationContext();


org.springframework.web.servlet.FrameworkServlet#initWebApplicationContext

configureAndRefreshWebApplicationContext(cwac);


org.springframework.web.servlet.FrameworkServlet#configureAndRefreshWebApplicationContext

wac.refresh();


org.springframework.context.support.AbstractApplicationContext#refresh

//xml解析
//注解的解析
ConfigurableListableBeanFactory beanFactory &＃61; obtainFreshBeanFactory();


org.springframework.context.support.AbstractApplicationContext#obtainFreshBeanFactory

refreshBeanFactory();


org.springframework.context.support.AbstractRefreshableApplicationContext#refreshBeanFactory

//实现类有xml解析和注解的解析
loadBeanDefinitions(beanFactory);


xml解析

org.springframework.context.support.AbstractXmlApplicationContext#loadBeanDefinitions(org.springframework.beans.factory.support.DefaultListableBeanFactory)

loadBeanDefinitions(beanDefinitionReader);


org.springframework.context.support.AbstractXmlApplicationContext#loadBeanDefinitions(org.springframework.beans.factory.xml.XmlBeanDefinitionReader)

//xml文件变为 Resource 对象后&＃xff0c;解析
reader.loadBeanDefinitions(configResources);


org.springframework.beans.factory.support.AbstractBeanDefinitionReader#loadBeanDefinitions(org.springframework.core.io.Resource…)

for (Resource resource : resources) {// xml 解析counter &＃43;&＃61; loadBeanDefinitions(resource);
}


org.springframework.beans.factory.xml.XmlBeanDefinitionReader#loadBeanDefinitions(org.springframework.core.io.Resource)

return loadBeanDefinitions(new EncodedResource(resource));


org.springframework.beans.factory.xml.XmlBeanDefinitionReader#loadBeanDefinitions(org.springframework.core.io.support.EncodedResource)

try {//文件流InputStream inputStream &＃61; encodedResource.getResource().getInputStream();try {// InputSource 是 dk 中的 xml 解析对象InputSource inputSource &＃61; new InputSource(inputStream);if (encodedResource.getEncoding() !&＃61; null) {inputSource.setEncoding(encodedResource.getEncoding());}// xml 解析return doLoadBeanDefinitions(inputSource, encodedResource.getResource());}finally {inputStream.close();}}


org.springframework.beans.factory.xml.XmlBeanDefinitionReader#doLoadBeanDefinitions

try {// xml 解析为 Document 对象Document doc &＃61; doLoadDocument(inputSource, resource);return registerBeanDefinitions(doc, resource);}


org.springframework.beans.factory.xml.XmlBeanDefinitionReader#registerBeanDefinitions

public int registerBeanDefinitions(Document doc, Resource resource) throws BeanDefinitionStoreException {//xml 文档解析器BeanDefinitionDocumentReader documentReader &＃61; createBeanDefinitionDocumentReader();int countBefore &＃61; getRegistry().getBeanDefinitionCount();documentReader.registerBeanDefinitions(doc, createReaderContext(resource));return getRegistry().getBeanDefinitionCount() - countBefore;}


org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#registerBeanDefinitions

xml 文件中的根节点&＃xff0c;即 <beans>
Element root &＃61; doc.getDocumentElement();
doRegisterBeanDefinitions(root);


org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#doRegisterBeanDefinitions

parseBeanDefinitions(root, this.delegate);


org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#parseBeanDefinitions

protected void parseBeanDefinitions(Element root, BeanDefinitionParserDelegate delegate) {if (delegate.isDefaultNamespace(root)) {NodeList nl &＃61; root.getChildNodes();for (int i &＃61; 0; i < nl.getLength(); i&＃43;&＃43;) {Node node &＃61; nl.item(i);if (node instanceof Element) {Element ele &＃61; (Element) node;if (delegate.isDefaultNamespace(ele)) {//解析 xml 中默认的元素&＃xff0c;默认标签&＃xff1a;import 、alias、bean、beansparseDefaultElement(ele, delegate);}else {// 解析 xml 中 自定义的元素delegate.parseCustomElement(ele);}}}}else {delegate.parseCustomElement(root);}}


org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#parseDefaultElement

// bean 标签解析
processBeanDefinition(ele, delegate);


org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#processBeanDefinition

BeanDefinitionHolder bdHolder &＃61; delegate.parseBeanDefinitionElement(ele);


org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseBeanDefinitionElement(org.w3c.dom.Element, org.springframework.beans.factory.config.BeanDefinition)

String beanName &＃61; id;
AbstractBeanDefinition beanDefinition &＃61;
parseBeanDefinitionElement(ele, beanName, containingBean);


org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseBeanDefinitionElement(org.w3c.dom.Element, java.lang.String, org.springframework.beans.factory.config.BeanDefinition)

AbstractBeanDefinition bd &＃61;
createBeanDefinition(className, parent);


org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#createBeanDefinition

return BeanDefinitionReaderUtils.createBeanDefinition(parentName, className,this.readerContext.getBeanClassLoader());


org.springframework.beans.factory.support.BeanDefinitionReaderUtils#createBeanDefinition

GenericBeanDefinition bd &＃61; new GenericBeanDefinition();bd.setParentName(parentName);if (className !&＃61; null) {if (classLoader !&＃61; null) {// 获取 class 元素配置的类bd.setBeanClass(ClassUtils.forName(className, classLoader));}else {bd.setBeanClassName(className);}}return bd;


返回到
org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseBeanDefinitionElement(org.w3c.dom.Element, java.lang.String, org.springframework.beans.factory.config.BeanDefinition)

//得到 BeanDefinition 对象
AbstractBeanDefinition bd &＃61; createBeanDefinition(className, parent);
//bean 标签上的元素解析&＃xff0c;并封装到 db 中&＃xff0c;即 BeanDefinition 对象中
parseBeanDefinitionAttributes(ele, beanName, containingBean, bd);


BeanDefinition 对象

1. 会把 xml 中的标签元素&＃xff0c;比如 bean,componentScan,annotation-config 标签中的元素信息封装成 BeanDefinition 对象&＃xff0c;
2. 会把 annotation &＃xff0c;比如 &＃64;Service、&＃64;Controller、&＃64;Component、&＃64;Resource 等注解的类&＃xff0c;封装成 BeanDefinition 对象

返回到
org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseBeanDefinitionElement(org.w3c.dom.Element, org.springframework.beans.factory.config.BeanDefinition)

AbstractBeanDefinition beanDefinition &＃61; parseBeanDefinitionElement(ele, beanName, containingBean);


返回到
org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#processBeanDefinition
返回到
org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#parseBeanDefinitions

// 自定义标签解析
delegate.parseCustomElement(ele);


org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseCustomElement(org.w3c.dom.Element)

return parseCustomElement(ele, null);


org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseCustomElement(org.w3c.dom.Element, org.springframework.beans.factory.config.BeanDefinition)

public BeanDefinition parseCustomElement(Element ele, BeanDefinition containingBd) {//元素的对应的 NamespaceURIString namespaceUri &＃61; getNamespaceURI(ele);//根据 NamespaceURI 拿到到应的处理类&＃xff0c;即 NamespaceHandler NamespaceHandler handler &＃61; this.readerContext.getNamespaceHandlerResolver().resolve(namespaceUri);if (handler &＃61;&＃61; null) {error("Unable to locate Spring NamespaceHandler for XML schema namespace [" &＃43; namespaceUri &＃43; "]", ele);return null;}return handler.parse(ele, new ParserContext(this.readerContext, this, containingBd));}


NamespaceURI 就是 beans 标签的 xmlns 、 xmlns:context、xmlns:aop、xmlns:tx 后面uri

org.springframework.beans.factory.xml.DefaultNamespaceHandlerResolver#resolve

Map<String, Object> handlerMappings &＃61; getHandlerMappings();


org.springframework.beans.factory.xml.DefaultNamespaceHandlerResolver#getHandlerMappings

//加载所有的配置文件
Properties mappings &＃61;
PropertiesLoaderUtils.loadAllProperties(this.handlerMappingsLocation, this.classLoader);Map<String, Object> handlerMappings &＃61; new ConcurrentHashMap<String, Object>(mappings.size());
CollectionUtils.mergePropertiesIntoMap(mappings, handlerMappings);
//返回这个 map,
this.handlerMappings &＃61; handlerMappings;


查看 4.3.12.RELEASE\spring-context-4.3.12.RELEASE.jar!\META-INF\spring.handlers
注册 spring context 自定义标签解析器 org.springframework.context.config.ContextNamespaceHandler
查看 spring-webmvc-4.3.12.RELEASE.jar!\META-INF\spring.handlers
注册 spring mvc 自定义的标签解析器 org.springframework.web.servlet.config.MvcNamespaceHandler
返回到
org.springframework.beans.factory.xml.DefaultNamespaceHandlerResolver#resolve

Map<String, Object> handlerMappings &＃61; getHandlerMappings();
Object handlerOrClassName &＃61; handlerMappings.get(namespaceUri);
// 例如&＃xff1a;handlerOrClassName 就是指 ContextNamespaceHandler
String className &＃61; (String) handlerOrClassName;
// new 出 ContextNamespaceHandler 的实例
NamespaceHandler namespaceHandler &＃61; (NamespaceHandler) BeanUtils.instantiateClass(handlerClass);
// 调用注册方法&＃xff0c;注册自定义标签的解析器
namespaceHandler.init();
//返回
return namespaceHandler;


返回到
org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseCustomElement(org.w3c.dom.Element, org.springframework.beans.factory.config.BeanDefinition)

String namespaceUri &＃61; getNamespaceURI(ele);
NamespaceHandler handler &＃61;
this.readerContext.getNamespaceHandlerResolver().resolve(namespaceUri);
return handler.parse(ele, new ParserContext(this.readerContext, this, containingBd));


org.springframework.beans.factory.xml.NamespaceHandlerSupport#parse

// 根据标签找到到应的解析器&＃xff0c;再调用 parse 方法解析标签&＃xff0c;即 element
return findParserForElement(element, parserContext).parse(element, parserContext);


org.springframework.beans.factory.xml.NamespaceHandlerSupport#findParserForElement

//得到标签对就的处理类
String localName &＃61; parserContext.getDelegate().getLocalName(element);
BeanDefinitionParser parser &＃61; this.parsers.get(localName);
return parser;


总结

1. spring 分析入口
2. xml 默认元素解析过程
3. xml 自定义标签配置和解析