/**
 * Tell the subclass to refresh the internal bean factory.
 * @return the fresh BeanFactory instance
 * @see #refreshBeanFactory()
 * @see #getBeanFactory()
 */
protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
   refreshBeanFactory();----》點選進入
   ConfigurableListableBeanFactory beanFactory = getBeanFactory();
if 
 
(logger.isDebugEnabled()) {
logger.debug("Bean factory for " + getDisplayName() + ": " + beanFactory);
   }
return beanFactory;
}

繼承關係圖

try {
      DefaultListableBeanFactory beanFactory = createBeanFactory();//例項化DefaultListableBeanFactory
      beanFactory.setSerializationId(getId());
      customizeBeanFactory(beanFactory);
      loadBeanDefinitions(beanFactory);  //解析XML  裝載成BeanDefinition物件  --》點選進入
synchronized (this.beanFactoryMonitor) {
this.beanFactory = beanFactory;
      }
   }
catch (IOException ex) {
throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex);
   }
}

===============================================================================

org.springframework.web.context.support.AbstractRefreshableApplicationContext.loadBeanDefinitions()方法 ---（抽象類AbstractRefreshableApplicationContext 分別被下面四個 類 實現

--》進入org.springframework.web.context.support.XmlWebApplicationContext--loadBeanDefinitions()方法

/**
 * 通過XmlBeanDefinitionReader 載入和定義bean
 * Loads the bean definitions via an XmlBeanDefinitionReader.
 * @see org.springframework.beans.factory.xml.XmlBeanDefinitionReader
 * @see #initBeanDefinitionReader
 * @see #loadBeanDefinitions
 */

@Override
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.
beanDefinitionReader.setEnvironment(getEnvironment());　//設定 StandardEnvironment 
   beanDefinitionReader.setResourceLoader(this);
   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);

  //解析spring配置的XXXXapplication.xml 具體執行-AbstractBeanDefinitionReader.loadBeanDefinitions()
   loadBeanDefinitions(beanDefinitionReader); 

XmlWebApplicationContext

執行：org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions()方法

目的：將spring xxxxApplication.xml--轉化為Resource 可以理解為IO流資源

下面的 resourceLoader 就是 XmlWebApplicationContext上一步方法賦值的 XmlWebApplicationContext 

public int loadBeanDefinitions(String location, Set<Resource> actualResources) throws BeanDefinitionStoreException {

   ResourceLoader resourceLoader = getResourceLoader(); 
if (resourceLoader == null) {
throw new BeanDefinitionStoreException(
"Cannot import bean definitions from location [" + location + "]: no ResourceLoader available");
   }

if (resourceLoader instanceof ResourcePatternResolver) {
// Resource pattern matching available.
try {
         Resource[] resources = ((ResourcePatternResolver) resourceLoader).getResources(location);
int loadCount = loadBeanDefinitions(resources); //進入--這裡以XML解析為例
if (actualResources != null) {
for (Resource resource : resources) {
               actualResources.add(resource);
            }
         }
if (logger.isDebugEnabled()) {
logger.debug("Loaded " + loadCount + " bean definitions from location pattern [" + location + "]");
         }
return loadCount;
      }
catch (IOException ex) {
throw new BeanDefinitionStoreException(
"Could not resolve bean definition resource pattern [" + location + "]", ex);
      }
   }
else {
// Can only load single resources by absolute URL.
Resource resource = resourceLoader.getResource(location);
int loadCount = loadBeanDefinitions(resource);
if (actualResources != null) {
         actualResources.add(resource);
      }
if (logger.isDebugEnabled()) {
logger.debug("Loaded " + loadCount + " bean definitions from location [" + location + "]");
      }
return loadCount;
   }
}

---》進入後 org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions()方法；主要作用 Resource--》EncodedResource（實現InputStreamSource）---》InputSource  IO流 

public int loadBeanDefinitions(EncodedResource encodedResource) throws BeanDefinitionStoreException {
   Assert.notNull(encodedResource, "EncodedResource must not be null");
if (logger.isInfoEnabled()) {
logger.info("Loading XML bean definitions from " + encodedResource.getResource());
   }

   Set<EncodedResource> currentResources = this.resourcesCurrentlyBeingLoaded.get();
if (currentResources == null) {
      currentResources = new HashSet<EncodedResource>(4);
this.resourcesCurrentlyBeingLoaded.set(currentResources);
   }
if (!currentResources.add(encodedResource)) {
throw new BeanDefinitionStoreException(
"Detected cyclic loading of " + encodedResource + " - check your import definitions!");
   }
try {
      InputStream inputStream = encodedResource.getResource().getInputStream();
try {
         InputSource inputSource = new InputSource(inputStream);
if (encodedResource.getEncoding() != null) {
            inputSource.setEncoding(encodedResource.getEncoding());
         }
return doLoadBeanDefinitions(inputSource, encodedResource.getResource());

        //上面的這條語句進入之後構造出 org.w3c.dom.Document doc = doLoadDocument(inputSource, resource);
        //之後的工作就是利用java api提供的Document解析XML

      }
finally {
         inputStream.close();
      }
   }

//各種不斷進入之後

org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.parseDefaultElement()方法

private void parseDefaultElement(Element ele, BeanDefinitionParserDelegate delegate) {

/**解析import 標籤的XML 例如： * <import resource="applicationContext-common.xml" /> * <import resource="applicationContext-datasource.xml" />* 進入importBeanDefinitionResource()--因為每個import引入一個xml spring 還是會向現在我們解析application.x *ml去解析一樣--裡面呼叫的方法 * int importCount = getReaderContext().getReader().loadBeanDefinitions(location, actualResources); * 執行的是org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions *( locatiom, actualResources)方法 ***/

if (delegate.nodeNameEquals(ele, IMPORT_ELEMENT)) {
      importBeanDefinitionResource(ele);
   }
else if (delegate.nodeNameEquals(ele, ALIAS_ELEMENT)) {
      processAliasRegistration(ele);
   }
else if (delegate.nodeNameEquals(ele, BEAN_ELEMENT)) {
      processBeanDefinition(ele, delegate); //解析bean<bean id="" class="" /> --進入

   }
else if (delegate.nodeNameEquals(ele, NESTED_BEANS_ELEMENT)) {
// recurse
doRegisterBeanDefinitions(ele);
   }
}

----》檢視解析進入bean的具體實現方法 org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader.processBeanDefinition()方法

解析：BeanDefinitionHolder bdHolder = delegate.parseBeanDefinitionElement(ele);

     1、對Element 屬性getAttribute（"id"/"name"）

     2、對獲得id/name 賦值給GenericBeanDefinition物件 它實現AbstractBeanDefinition-->BeanDefinition介面

（AbstractBeanDefinition物件就是儲存解析的bean 屬性 並對預設屬性賦值 id/name/scope/lazyInit/beanClass/initMethodName/propertyValues......)

        方法：AbstractBeanDefinition beanDefinition = parseBeanDefinitionElement(ele, beanName, conta              iningBean);

     3、構造返回 new BeanDefinitionHolder(beanDefinition，beanName,aliasesArray)  裡面就是beanName、

        aliasesArray、beanDefinition（物件） 方便後面spring 依賴注入直接通過beanName/aliasesArray（別名）        獲取beanDefinition物件。

   解析：BeanDefinitionReaderUtils.registerBeanDefinition(bdHolder, getReaderContext().getRegistry()

        1、獲取bdHolder的beanName和BeanDefinition 物件

        2、將BeanDefinitionRegistry----》registerBeanDefinition(beanName, definitionHolder.getBeanDefinition());

        3、將beanName 新增到List<String>，將beanName--key和beanDefinition--value 儲存到 Map<String, BeanDefinition> 中。