Spring源码解析-applicationContext
Demo
uml类图
ApplicationContext
ApplicationListener
源码解析
主流程
obtainFreshBeanFactory
prepareBeanFactory
invokeBeanFactoryPostProcessors
registerBeanPostProcessors
registerListeners
finishRefresh
总结
在已经有BeanFactory可以完成Ioc功能情况下，spring又提供了ApplicationContext，why？可以简单理解BeanFactory为可用，ApplicationContext封装了Beanfactory，提供了上下文、国际化、监听等更多的可选功能，让其能用，使用时，优先使用ApplicationContext。
Demo
跟beanfactory的demo唯一不同的就是：
//BeanFactoryctx=newXmlBeanFactory(newClassPathResource("spring.xml"));
ApplicationContextctx=newClassPathXmlApplicationContext("spring.xml");
uml类图
ApplicationContext
applicationContext
ApplicationListener
ApplicationListener
源码解析
主流程
//ClassPathXmlApplicationContext
publicClassPathXmlApplicationContext(String[]configLocations,booleanrefresh)throwsBeansException{
this(configLocations,refresh,null);
}
publicClassPathXmlApplicationContext(String[]configLocations,booleanrefresh,ApplicationContextparent)
throwsBeansException{
super(parent);
//设置configLocations
setConfigLocations(configLocations);
if(refresh){
refresh();
}
}
//AbstractApplicationContext
publicvoidrefresh()throwsBeansException,IllegalStateException{
synchronized(this.startupShutdownMonitor){
//设置和校验系统变量和环境变量的值
prepareRefresh();
//获取beanFactory
ConfigurableListableBeanFactorybeanFactory=obtainFreshBeanFactory();
//配置BeanFactory上下文
prepareBeanFactory(beanFactory);
try{
//子类扩展，beanFactory的后置处理
postProcessBeanFactory(beanFactory);
//调用BeanFactory的后置处理器
invokeBeanFactoryPostProcessors(beanFactory);
//注册beanprocessors，只是注册，bean创建时调用.
registerBeanPostProcessors(beanFactory);
//国际化
initMessageSource();
//初始化监听的Multicaster，有自定义就是用自定义，没有就使用默认SimpleApplicationEventMulticaster
initApplicationEventMulticaster();
//子类扩展
onRefresh();
//注册listen
registerListeners();
//实例化所有非延迟加载的bean，相当于循环调用getbean
finishBeanFactoryInitialization(beanFactory);
//完成刷新，通知LifecycleProcessor，ContextRefreshedEvent事件（这个很有用，可以监听这个事件）
finishRefresh();
}
catch(BeansExceptionex){
//Destroyalreadycreatedsingletonstoavoiddanglingresources.
destroyBeans();
//Reset''active''flag.
cancelRefresh(ex);
//Propagateexceptiontocaller.
throwex;
}
}
整个refresh过程，流程清晰，从spring学了这一招。
obtainFreshBeanFactory
这个流程里面有个需要注意的地方：
//AbstractRefreshableApplicationContext
protectedvoidcustomizeBeanFactory(DefaultListableBeanFactorybeanFactory){
if(this.allowBeanDefinitionOverriding!=null){
beanFactory.setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);
}
if(this.allowCircularReferences!=null){
beanFactory.setAllowCircularReferences(this.allowCircularReferences);
}
//用于@Autowire和@Qualifier，没试过，TODO
beanFactory.setAutowireCandidateResolver(newQualifierAnnotationAutowireCandidateResolver());
prepareBeanFactory
//ClassPathXmlApplicationContext
protectedvoidprepareBeanFactory(ConfigurableListableBeanFactorybeanFactory){
//Telltheinternalbeanfactorytousethecontext''sclassloaderetc.
beanFactory.setBeanClassLoader(getClassLoader());//之前beanfactory没有设置classLoader
beanFactory.setBeanExpressionResolver(newStandardBeanExpressionResolver());//el表达式
beanFactory.addPropertyEditorRegistrar(newResourceEditorRegistrar(this,this.getEnvironment()));//配置属性注入编辑器
//ApplicationContextAwareProcessor这个beanpostprocessor，在实例化前postProcessBeforeInitialization设置下面忽略的依赖
beanFactory.addBeanPostProcessor(newApplicationContextAwareProcessor(this));
beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
//设置几个自动注册的依赖，注入的时候直接用
beanFactory.registerResolvableDependency(BeanFactory.class,beanFactory);
beanFactory.registerResolvableDependency(ResourceLoader.class,this);
beanFactory.registerResolvableDependency(ApplicationEventPublisher.class,this);
beanFactory.registerResolvableDependency(ApplicationContext.class,this);
//aop类加载期织入支持DetectaLoadTimeWeaverandprepareforweaving,iffound.
if(beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)){
beanFactory.addBeanPostProcessor(newLoadTimeWeaverAwareProcessor(beanFactory));
//SetatemporaryClassLoaderfortypematching.
beanFactory.setTempClassLoader(newContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}
////注册一些默认bean，方便使用
if(!beanFactory.containsBean(ENVIRONMENT_BEAN_NAME)){
beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME,getEnvironment());
}
if(!beanFactory.containsBean(SYSTEM_PROPERTIES_BEAN_NAME)){
beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME,getEnvironment().getSystemProperties());
}
if(!beanFactory.containsBean(SYSTEM_ENVIRONMENT_BEAN_NAME)){
beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME,getEnvironment().getSystemEnvironment());
}
invokeBeanFactoryPostProcessors
//AbstractApplicationContext
//BeanFactoryPostProcessor激活调用
protectedvoidinvokeBeanFactoryPostProcessors(ConfigurableListableBeanFactorybeanFactory){
//InvokeBeanDefinitionRegistryPostProcessorsfirst,ifany.
SetprocessedBeans=newHashSet();
//BeanDefinitionRegistry中的BeanPostProcessor
if(beanFactoryinstanceofBeanDefinitionRegistry){
BeanDefinitionRegistryregistry=(BeanDefinitionRegistry)beanFactory;
ListregularPostProcessors=newLinkedList();
ListregistryPostProcessors=
newLinkedList();
//硬编码进来的
for(BeanFactoryPostProcessorpostProcessor:getBeanFactoryPostProcessors()){
if(postProcessorinstanceofBeanDefinitionRegistryPostProcessor){
//BeanDefinitionRegistryPostProcessor继承了BeanFactoryPostProcessor，多了个调用postProcessBeanDefinitionRegistry，这里区分下
BeanDefinitionRegistryPostProcessorregistryPostProcessor=
(BeanDefinitionRegistryPostProcessor)postProcessor;
registryPostProcessor.postProcessBeanDefinitionRegistry(registry);
registryPostProcessors.add(registryPostProcessor);
}
else{
regularPostProcessors.add(postProcessor);
}
}
//配置的bean中获取
MapbeanMap=
beanFactory.getBeansOfType(BeanDefinitionRegistryPostProcessor.class,true,false);
ListregistryPostProcessorBeans=
newArrayList(beanMap.values());
OrderComparator.sort(registryPostProcessorBeans);
for(BeanDefinitionRegistryPostProcessorpostProcessor:registryPostProcessorBeans){
//调用postProcessBeawww.tt951.comnDefinitionRegistry
postProcessor.postProcessBeanDefinitionRegistry(registry);
}
//调用postProcessBeanFactory
invokeBeanFactoryPostProcessors(registryPostProcessors,beanFactory);
invokeBeanFactoryPostProcessors(registryPostProcessorBeans,beanFactory);
invokeBeanFactoryPostProcessors(regularPostProcessors,beanFactory);
//processedBeans包含所有处理过的
processedBeans.addAll(beanMap.keySet());
}
else{
//Invokefactoryprocessorsregisteredwiththecontextinstance.
invokeBeanFactoryPostProcessors(getBeanFactoryPostProcessors(),beanFactory);
}
//beanFactory中获取BeanFactoryPostProcessor
String[]postProcessorNames=
beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class,true,false);
//SeparatebetweenBeanFactoryPostProcessorsthatimplementPriorityOrdered,
//Ordered,andtherest.
ListpriorityOrderedPostProcessors=newArrayList();
ListorderedPostProcessorNames=newArrayList();
ListnonOrderedPostProcessorNames=newArrayList();
for(StringppName:postProcessorNames){
//按照PriorityOrdered\Ordered\其他区分下，如果已经处理过，会过滤掉，不会重复处理
if(processedBeans.contains(ppName)){
//skip-alreadyprocessedinfirstphaseabove
}
elseif(isTypeMatch(ppName,PriorityOrdered.class)){
priorityOrderedPostProcessors.add(beanFactory.getBean(ppName,BeanFactoryPostProcessor.class));
}
elseif(isTypeMatch(ppName,Ordered.class)){
orderedPostProcessorNames.add(ppName);
}
else{
nonOrderedPostProcessorNames.add(ppName);
}
}
//对分类过的排序然后调用
//First,invoketheBeanFactoryPostProcessorsthatimplementPriorityOrdered.
OrderComparator.sort(priorityOrderedPostProcessors);
invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors,beanFactory);
//Next,invoketheBeanFactoryPostProcessorsthatimplementOrdered.
ListorderedPostProcessors=newArrayList();
for(StringpostProcessorName:orderedPostProcessorNames){
orderedPostProcessors.add(getBean(postProcessorName,BeanFactoryPostProcessor.class));
}
OrderComparator.sort(orderedPostProcessors);
invokeBeanFactoryPostProcessors(orderedPostProcessors,beanFactory);
//Finally,invokeallotherBeanFactoryPostProcessors.
ListnonOrderedPostProcessors=newArrayList();
for(StringpostProcessorName:nonOrderedPostProcessorNames){
nonOrderedPostProcessors.add(getBean(postProcessorName,BeanFactoryPostProcessor.class));
}
invokeBeanFactoryPostProcessors(nonOrderedPostProcessors,beanFactory);
registerBeanPostProcessors
//AbstractApplicationContext
//注册所有的BeanPostProcessor，只注册，不调用
protectedvoidregisterBeanPostProcessors(ConfigurableListableBeanFactorybeanFactory){
String[]postProcessorNames=beanFactory.getBeanNamesForType(BeanPostProcessor.class,true,false);
//注册BeanPostProcessorChecker，只是info日志表明bean没有被所有processor处理，没感觉想干嘛
intbeanProcessorTargetCount=beanFactory.getBeanPostProcessorCount()+1+postProcessorNames.length;
beanFactory.addBeanPostProcessor(newBeanPostProcessorChecker(beanFactory,beanProcessorTargetCount));
//按照实现PriorityOrdered,Ordered,其他.分类排序注册到beanfactory
ListpriorityOrderedPostProcessors=newArrayList();
ListinternalPostProcessors=newArrayList();
ListorderedPostProcessorNames=newArrayList();
ListnonOrderedPostProcessorNames=newArrayList();
for(StringppName:postProcessorNames){
if(isTypeMatch(ppName,PriorityOrdered.class)){
BeanPostProcessorpp=beanFactory.getBean(ppName,BeanPostProcessor.class);
priorityOrderedPostProcessors.add(pp);
if(ppinstanceofMergedBeanDefinitionPostProcessor){
internalPostProcessors.add(pp);
}
}
elseif(isTypeMatch(ppName,Ordered.class)){
orderedPostProcessorNames.add(ppName);
}
else{
nonOrderedPostProcessorNames.add(ppName);
}
}
//First,registertheBeanPostProcessorsthatimplementPriorityOrdered.
OrderComparator.sort(priorityOrderedPostProcessors);
registerBeanPostProcessors(beanFactory,priorityOrderedPostProcessors);
//Next,registertheBeanPostProcessorsthatimplementOrdered.
ListorderedPostProcessors=newArrayList();
for(StringppName:orderedPostProcessorNames){
BeanPostProcessorpp=beanFactory.getBean(ppName,BeanPostProcessor.class);
orderedPostProcessors.add(pp);
if(ppinstanceofMergedBeanDefinitionPostProcessor){
internalPostProcessors.add(pp);
}
}
OrderComparator.sort(orderedPostProcessors);
registerBeanPostProcessors(beanFactory,orderedPostProcessors);
//Now,registerallregularBeanPostProcessors.
ListnonOrderedPostProcessors=newArrayList();
for(StringppName:nonOrderedPostProcessorNames){
BeanPostProcessorpp=beanFactory.getBean(ppName,BeanPostProcessor.class);
nonOrderedPostProcessors.add(pp);
if(ppinstanceofMergedBeanDefinitionPostProcessor){
internalPostProcessors.add(pp);
}
}
registerBeanPostProcessors(beanFactory,nonOrderedPostProcessors);
//Finally,re-registerallinternalBeanPostProcessors.
OrderComparator.sort(internalPostProcessors);
registerBeanPostProcessors(beanFactory,internalPostProcessors);
//ApplicationListenerDetector初始化后，如果是listener，添加到监听里面
beanFactory.addBeanPostProcessor(newApplicationListenerDetector());
}
//注册所有的BeanPostProcessor到Beanfactory
privatevoidregisterBeanPostProcessors(
ConfigurableListableBeanFactorybeanFactory,ListpostProcessors){
for(BeanPostProcessorpostProcessor:postProcessors){
beanFactory.addBeanPostProcessor(postProcessor);
}
只注册，不调用，跟beanfactoryprocessor不一样。
registerListeners
//AbstractApplicationContext
protectedvoidregisterListeners(){
//注册硬编码的listener
for(ApplicationListenerlistener:getApplicationListeners()){
getApplicationEventMulticaster().addApplicationListener(listener);
}
//注册xml配置的listener
String[]listenerBeanNames=getBeanNamesForType(ApplicationListener.class,true,false);
for(StringlisName:listenerwww.baiyuewang.netBeanNames){
getApplicationEventMulticaster().addApplicationListenerBean(lisName);
}
finishRefresh
//AbstractApplicationContext
protectedvoidfinishRefresh(){
//初始化LifecycleProcessor，有自定义就使用自定义的，没有就使用DefaultLifecycleProcessor（onRefresh和onClose）
initLifecycleProcessor();
//广播onRefresh给所有实现lifeProcessor
getLifecycleProcessor().onRefresh();
//PublishContextRefreshedEvent事件
publishEvent(newContextRefreshedEvent(this));
}
可以通过监听ContextRefreshedEvent事件，在所有applicationContext完成所有操作后修改bean，做其他操作。
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