spring XmlWebApplicationContext详解

XmlWebApplicationContext是spring在web应用中的context，

在ContextLoaderListener或ContextLoaderServlet中完成了初步的设置。

XmlWebApplicationContext跟其他的applicationContext（FileSystem，Classpath）一样，是AbstractApplicationContext的一个子类。

applicationContext的refresh过程是线程同步的。

如下：

synchronized (this.startupShutdownMonitor)

方法1

prepareRefresh(); //设定起始时间，并设置active标记

方法2

// 通知子类完成BeanFactory的创建。

ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {

refreshBeanFactory();

ConfigurableListableBeanFactory beanFactory = getBeanFactory();

if (logger.isDebugEnabled()) {

logger.debug("Bean factory for " + getDisplayName() + ": " + beanFactory);

}

return beanFactory;

}

refreshBeanFactory 在AbstractRefreshableApplicationContext（是XmlWebApplicationContext的父类）中进行了实现。创建了DefaultListableBeanFactory,随后执行

loadBeanDefinitions(beanFactory);这个是在XmlWebApplicationContext中进行了实现。

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.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);

loadBeanDefinitions(beanDefinitionReader);

}

该方法中的beanDefinitionReader完成了WEB-INF/applicationContext.xml(可指定contextConfigLoaction的值，可使用,; \t\n指定多个applicationContext.xml文件)的加载

// 上面浅黄色的方法如下

protected void loadBeanDefinitions(XmlBeanDefinitionReader reader) throws IOException {

String[] configLocations = getConfigLocations();

if (configLocations != null) {

for (String configLocation : configLocations) {

reader.loadBeanDefinitions(configLocation);// 完成所有applicationContext.xml的加载

}

}

}

具体的xmlreader的装载再以后详细阅读。继续分析xmlwebApplicationContext的refresh过程。

方法3

prepareBeanFactory(beanFactory);

部分代码：

beanFactory.setBeanClassLoader(getClassLoader()); //设定类加载器

// 设定spring的EL解决器

beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver());

beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this));

代码复杂，慢慢研究：

// Allows post-processing of the bean factory in context subclasses.

postProcessBeanFactory(beanFactory);

// Invoke factory processors registered as beans in the context.

invokeBeanFactoryPostProcessors(beanFactory);

// Register bean processors that intercept bean creation.

registerBeanPostProcessors(beanFactory);

// Initialize message source for this context.

initMessageSource();

// Initialize event multicaster for this context.

initApplicationEventMulticaster();

// Initialize other special beans in specific context subclasses.

onRefresh();

// Check for listener beans and register them.

registerListeners();

// Instantiate all remaining (non-lazy-init) singletons.

finishBeanFactoryInitialization(beanFactory);

// Last step: publish corresponding event.

finishRefresh();

文章出自：http://hi.baidu.com/yuanyuan1027/blog/item/9727c9dfd04d4a5995ee3723.html