前面的章节介绍了SpringIoC的基础容器BeanFactory，接下来的章节分析Spring的高级容器ApplicationContext。关于两者的介绍，可以参考以前的章节。接下来我们以ClassPathXmlApplicationContext为例分析ApplicationContext的创建过程。
引、ApplicationContext创建过程简析
/**
* 创建一个新的ClassPathXmlApplicationContext容器
* 从指定的xml文件加载BeanDefinition并自动刷新容器
* @param configLocation 配置文件位置
* @throws BeansException 容器创建失败，抛出BeansException异常
*/
public ClassPathXmlApplicationContext(String configLocation) throws BeansException {
this(new String[] {configLocation}, true, null);
}
public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh, @Nullable ApplicationContext parent) throws BeansException {
// 调用父类构造器
super(parent);
// 设定配置文件路径
setConfigLocations(configLocations);
if (refresh) {
// 扩展功能
refresh();
}
}
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// 1、准备刷新上下文环境
prepareRefresh();
// 2、读取xml并初始化BeanFactory
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// 3、填充BeanFactory功能
prepareBeanFactory(beanFactory);
try {
// 4、子类覆盖方法额外处理(空方法)
postProcessBeanFactory(beanFactory);
// 5、调动BeanFactoryPostProcessor
invokeBeanFactoryPostProcessors(beanFactory);
// 6、注册BeanPostProcessors
registerBeanPostProcessors(beanFactory);
// 7、初始化Message资源
initMessageSource();
// 8、初始事件广播器
initApplicationEventMulticaster();
// 9、留给子类初始化其他Bean(空的模板方法)
onRefresh();
// 10、注册事件监听器
registerListeners();
// 11、初始化其他的单例Bean(非延迟加载的)
finishBeanFactoryInitialization(beanFactory);
// 12、完成刷新过程,通知生命周期处理器lifecycleProcessor刷新过程,同时发出ContextRefreshEvent通知
finishRefresh();
}
catch (BeansException ex) {
// 13、销毁已经创建的Bean
destroyBeans();
// 14、重置容器激活标签
cancelRefresh(ex);
throw ex;
}
finally {
resetCommonCaches();
}
}
}
逐步分析refresh()方法。
1、prepareRefresh刷新上下文的准备工作
/**
* 准备刷新上下文环境，设置它的启动日期和活动标志，以及执行任何属性源的初始化。
* Prepare this context for refreshing, setting its startup date and
* active flag as well as performing any initialization of property sources.
*/
protected void prepareRefresh() {
this.startupDate = System.currentTimeMillis();
this.closed.set(false);
this.active.set(true);
// 在上下文环境中初始化任何占位符属性源。(空的方法,留给子类覆盖)
initPropertySources();
// 验证需要的属性文件是否都已放入环境中
getEnvironment().validateRequiredProperties();
// 允许收集早期的应用程序事件，一旦有了多播器，就可以发布……
this.earlyApplicationEvents = new LinkedHashSet<>();
}
2、obtainFreshBeanFactory->读取xml并初始化BeanFactory
protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
// 刷新BeanFactory并返回BeanFactory对象
refreshBeanFactory();
return getBeanFactory();
}
protected final void refreshBeanFactory() throws BeansException {
// 1、如果BeanFactory的实例已经存在,则销毁并关闭
if (hasBeanFactory()) {
destroyBeans();
closeBeanFactory();
}
// 2、重新创建BeanFactory
try {
// 创建BeanFactory
DefaultListableBeanFactory beanFactory = createBeanFactory();
// 为BeanFactory设置id
beanFactory.setSerializationId(getId());
// 定制beanFactory
customizeBeanFactory(beanFactory);
// 加载BeanDefinition
loadBeanDefinitions(beanFactory);
synchronized (this.beanFactoryMonitor) {
this.beanFactory = beanFactory;
}
}
catch (IOException ex) {
throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex);
}
}
该方法的主要作用就是保证获取一个全新的beanFactory，关于beanFactory我们在前面已经做了很多介绍了，这里不在说明。
3、prepareBeanFactory-->填充BeanFactory功能
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
// Tell the internal bean factory to use the context's class loader etc.
// 设置beanFactory的classLoader
beanFactory.setBeanClassLoader(getClassLoader());
// 设置beanFactory的表达式语言处理器,Spring3开始增加了对语言表达式的支持,默认可以使用#{bean.xxx}的形式来调用相关属性值
beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
// 为beanFactory增加一个默认的propertyEditor,这个主要是对bean的属性等设置管理的一个工具
beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));
// Configure the bean factory with context callbacks.
// 添加ApplicationContextAwareProcessor
beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
// 设置忽略自动装配的接口
beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
// BeanFactory interface not registered as resolvable type in a plain factory.
// MessageSource registered (and found for autowiring) as a bean.
// 设置几个自动装配的特殊规则
beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
beanFactory.registerResolvableDependency(ResourceLoader.class, this);
beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
beanFactory.registerResolvableDependency(ApplicationContext.class, this);
// Register early post-processor for detecting inner beans as ApplicationListeners.
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));
// Detect a LoadTimeWeaver and prepare for weaving, if found.
// 增加对AspectJ的支持
if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
// Set a temporary ClassLoader for type matching.
beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}
// Register default environment beans.
// 注册默认的系统环境bean
if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) {
beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment());
}
if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) {
beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties());
}
if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) {
beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment());
}
}
4、postProcessBeanFactory
该方法是个空的模板方法。
5、invokeBeanFactoryPostProcessors-->调用BeanFactoryPostProcessor
BeanFactoryPostProcessor在Spring中非常重要，详细分析其调用过程。
protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
//getBeanFactoryPostProcessors->获取注册的BeanFactoryPostProcessor
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());
// Detect a LoadTimeWeaver and prepare for weaving, if found in the meantime
// (e.g. through an @Bean method registered by ConfigurationClassPostProcessor)
if (beanFactory.getTempClassLoader() == null && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}
}
通过PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());获取注册的BeanFactoryPostProcessor并调用。
public static void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {
// Invoke BeanDefinitionRegistryPostProcessors first, if any.
// 1、首先调用BeanDefinitionRegistryPostProcessors
Set<String> processedBeans = new HashSet<>();
// beanFactory是BeanDefinitionRegistry类型
if (beanFactory instanceof BeanDefinitionRegistry) {
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
// 定义BeanFactoryPostProcessor
List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();
// 定义BeanDefinitionRegistryPostProcessor集合
List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();
// 循环手动注册的beanFactoryPostProcessors
for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
// 如果是BeanDefinitionRegistryPostProcessor的实例话,则调用其postProcessBeanDefinitionRegistry方法,对bean进行注册操作
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
// 如果是BeanDefinitionRegistryPostProcessor类型,则直接调用其postProcessBeanDefinitionRegistry
BeanDefinitionRegistryPostProcessor registryProcessor = (BeanDefinitionRegistryPostProcessor) postProcessor;
registryProcessor.postProcessBeanDefinitionRegistry(registry);
registryProcessors.add(registryProcessor);
}
// 否则则将其当做普通的BeanFactoryPostProcessor处理,直接加入regularPostProcessors集合,以备后续处理
else {
regularPostProcessors.add(postProcessor);
}
}
// Do not initialize FactoryBeans here: We need to leave all regular beans
// uninitialized to let the bean factory post-processors apply to them!
// Separate between BeanDefinitionRegistryPostProcessors that implement
// PriorityOrdered, Ordered, and the rest.
List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>();
// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
// 首先调用实现了PriorityOrdered(有限排序接口)的BeanDefinitionRegistryPostProcessors
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
}
}
// 排序
sortPostProcessors(currentRegistryProcessors, beanFactory);
// 加入registryProcessors集合
registryProcessors.addAll(currentRegistryProcessors);
// 调用所有实现了PriorityOrdered的的BeanDefinitionRegistryPostProcessors的postProcessBeanDefinitionRegistry方法,注册bean
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
// 清空currentRegistryProcessors,以备下次使用
currentRegistryProcessors.clear();
// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
// 其次,调用实现了Ordered(普通排序接口)的BeanDefinitionRegistryPostProcessors
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
}
}
// 排序
sortPostProcessors(currentRegistryProcessors, beanFactory);
// 加入registryProcessors集合
registryProcessors.addAll(currentRegistryProcessors);
// 调用所有实现了PriorityOrdered的的BeanDefinitionRegistryPostProcessors的postProcessBeanDefinitionRegistry方法,注册bean
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
// 清空currentRegistryProcessors,以备下次使用
currentRegistryProcessors.clear();
// Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear.
// 最后,调用其他的BeanDefinitionRegistryPostProcessors
boolean reiterate = true;
while (reiterate) {
reiterate = false;
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
if (!processedBeans.contains(ppName)) {
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
reiterate = true;
}
}
// 排序
sortPostProcessors(currentRegistryProcessors, beanFactory);
// 加入registryProcessors集合
registryProcessors.addAll(currentRegistryProcessors);
// 调用其他的BeanDefinitionRegistryPostProcessors的postProcessBeanDefinitionRegistry方法,注册bean
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
// 清空currentRegistryProcessors,以备下次使用
currentRegistryProcessors.clear();
}
// Now, invoke the postProcessBeanFactory callback of all processors handled so far.
// 调用所有BeanDefinitionRegistryPostProcessor(包括手动注册和通过配置文件注册)
// 和BeanFactoryPostProcessor(只有手动注册)的回调函数-->postProcessBeanFactory
invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
}
// 2、如果不是BeanDefinitionRegistry的实例,那么直接调用其回调函数即可-->postProcessBeanFactory
else {
// Invoke factory processors registered with the context instance.
invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);
}
// Do not initialize FactoryBeans here: We need to leave all regular beans
// uninitialized to let the bean factory post-processors apply to them!
// 3、上面的代码已经处理完了所有的BeanDefinitionRegistryPostProcessors和手动注册的BeanFactoryPostProcessor
// 接下来要处理通过配置文件注册的BeanFactoryPostProcessor
// 首先获取所有的BeanFactoryPostProcessor(注意:这里获取的集合会包含BeanDefinitionRegistryPostProcessors)
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
// Separate between BeanFactoryPostProcessors that implement PriorityOrdered, Ordered, and the rest.
// 这里,将实现了PriorityOrdered,Ordered的处理器和其他的处理器区分开来,分别进行处理
// PriorityOrdered有序处理器
List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
// Ordered有序处理器
List<String> orderedPostProcessorNames = new ArrayList<>();
// 无序处理器
List<String> nonOrderedPostProcessorNames = new ArrayList<>();
for (String ppName : postProcessorNames) {
// 判断processedBeans是否包含当前处理器(processedBeans中的处理器已经被处理过);如果包含,则不做任何处理
if (processedBeans.contains(ppName)) {
// skip - already processed in first phase above
}
else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
// 加入到PriorityOrdered有序处理器集合
priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
// 加入到Ordered有序处理器集合
orderedPostProcessorNames.add(ppName);
}
else {
// 加入到无序处理器集合
nonOrderedPostProcessorNames.add(ppName);
}
}
// First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.
// 首先调用实现了PriorityOrdered接口的处理器
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);
// Next, invoke the BeanFactoryPostProcessors that implement Ordered.
// 其次,调用实现了Ordered接口的处理器
List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>();
for (String postProcessorName : orderedPostProcessorNames) {
orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
sortPostProcessors(orderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);
// Finally, invoke all other BeanFactoryPostProcessors.
// 最后,调用无序处理器
List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>();
for (String postProcessorName : nonOrderedPostProcessorNames) {
nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);
// Clear cached merged bean definitions since the post-processors might have
// modified the original metadata, e.g. replacing placeholders in values...
// 清理元数据
beanFactory.clearMetadataCache();
}
public static void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);
// Register BeanPostProcessorChecker that logs an info message when
// a bean is created during beanPostProcessor instantiation, i.e. when
// a bean is not eligible for getting processed by all BeanPostProcessors.
// 注册一个BeanPostProcessorChecker,它是BeanPostProcessor的子类
// 用于在BeanPostProcessor实例化期间创建bean时记录信息消息，即当bean不符合由所有BeanPostProcessors处理的资格时。
int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));
// Separate between BeanPostProcessors that implement PriorityOrdered, Ordered, and the rest.
// 对实现了PriorityOrdered接口,Ordered接口,内部BeanPostProcessor和其他的BeanPostProcessor分类处理
List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
List<BeanPostProcessor> internalPostProcessors = new ArrayList<>();
List<String> orderedPostProcessorNames = new ArrayList<>();
List<String> nonOrderedPostProcessorNames = new ArrayList<>();
for (String ppName : postProcessorNames) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
priorityOrderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessorNames.add(ppName);
}
else {
nonOrderedPostProcessorNames.add(ppName);
}
}
// First, register the BeanPostProcessors that implement PriorityOrdered.
// 首先注册实现了PriorityOrdered(有限排序接口)BeanPostProcessor
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);
// Next, register the BeanPostProcessors that implement Ordered.
// 其次,注册实现了Ordered(排序接口的)BeanPostProcessor
List<BeanPostProcessor> orderedPostProcessors = new ArrayList<>();
for (String ppName : orderedPostProcessorNames) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
orderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
sortPostProcessors(orderedPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, orderedPostProcessors);
// Now, register all regular BeanPostProcessors.
// 然后,注册无序的BeanPostProcessors
List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>();
for (String ppName : nonOrderedPostProcessorNames) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
nonOrderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);
// Finally, re-register all internal BeanPostProcessors.
// 最后,注册内部BeanPostProcessors
sortPostProcessors(internalPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, internalPostProcessors);
// Re-register post-processor for detecting inner beans as ApplicationListeners,
// moving it to the end of the processor chain (for picking up proxies etc).
// 注册一个ApplicationListenerDetector用来侦测ApplicationListener类型的bean
// 并将它们加入到容器的applicationEventMulticaster或applicationListeners集合中
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}
6、注册BeanPostProcessors
protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {
PostProcessorRegistrationDelegate.registerBeanPostProcessors(beanFactory, this);
}
public static void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);
// Register BeanPostProcessorChecker that logs an info message when
// a bean is created during beanPostProcessor instantiation, i.e. when
// a bean is not eligible for getting processed by all BeanPostProcessors.
// 1、注册一个BeanPostProcessorChecker,它是BeanPostProcessor的子类
// 用于在BeanPostProcessor实例化期间创建bean时记录信息消息，即当bean不符合由所有BeanPostProcessors处理的资格时。
int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));
// Separate between BeanPostProcessors that implement PriorityOrdered, Ordered, and the rest.
// 2、对实现了PriorityOrdered接口,Ordered接口,内部BeanPostProcessor和其他的BeanPostProcessor分类处理
List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
List<BeanPostProcessor> internalPostProcessors = new ArrayList<>();
List<String> orderedPostProcessorNames = new ArrayList<>();
List<String> nonOrderedPostProcessorNames = new ArrayList<>();
for (String ppName : postProcessorNames) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
priorityOrderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessorNames.add(ppName);
}
else {
nonOrderedPostProcessorNames.add(ppName);
}
}
// 3、注册BeanPostProcessors
// First, register the BeanPostProcessors that implement PriorityOrdered.
// 首先注册实现了PriorityOrdered(有限排序接口)BeanPostProcessor
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);
// Next, register the BeanPostProcessors that implement Ordered.
// 其次,注册实现了Ordered(排序接口的)BeanPostProcessor
List<BeanPostProcessor> orderedPostProcessors = new ArrayList<>();
for (String ppName : orderedPostProcessorNames) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
orderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
sortPostProcessors(orderedPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, orderedPostProcessors);
// Now, register all regular BeanPostProcessors.
// 然后,注册无序的BeanPostProcessors
List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>();
for (String ppName : nonOrderedPostProcessorNames) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
nonOrderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);
// Finally, re-register all internal BeanPostProcessors.
// 最后,注册内部BeanPostProcessors
sortPostProcessors(internalPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, internalPostProcessors);
// Re-register post-processor for detecting inner beans as ApplicationListeners,
// moving it to the end of the processor chain (for picking up proxies etc).
// 注册一个ApplicationListenerDetector用来侦测ApplicationListener类型的bean
// 并将它们加入到容器的applicationEventMulticaster或applicationListeners集合中
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}
7、初始化Message资源
该方法不是很重要，留在以后分析吧。。。
8、初始事件广播器
protected void initApplicationEventMulticaster() {
ConfigurableListableBeanFactory beanFactory = getBeanFactory();
// 1、默认使用内置的事件广播器,如果有的话.
// 我们可以在配置文件中配置Spring事件广播器或者自定义事件广播器
// 例如: <bean id="applicationEventMulticaster" class="org.springframework.context.event.SimpleApplicationEventMulticaster"></bean>
if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
this.applicationEventMulticaster = beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
}
// 2、否则,新建一个事件广播器,SimpleApplicationEventMulticaster是spring的默认事件广播器
else {
this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
}
}
9、onRefresh-->留给子类初始化其他Bean
该方法是个空的模板方法
10、注册事件监听器
protected void registerListeners() {
// Register statically specified listeners first.
// 首先,注册指定的静态事件监听器,在spring boot中有应用
for (ApplicationListener<?> listener : getApplicationListeners()) {
getApplicationEventMulticaster().addApplicationListener(listener);
}
// Do not initialize FactoryBeans here: We need to leave all regular beans
// uninitialized to let post-processors apply to them!
// 其次,注册普通的事件监听器
String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);
for (String listenerBeanName : listenerBeanNames) {
getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);
}
// Publish early application events now that we finally have a multicaster...
// 如果有早期事件的话,在这里进行事件广播
// 因为前期SimpleApplicationEventMulticaster尚未注册，无法发布事件，
// 因此早期的事件会先存放在earlyApplicationEvents集合中，这里把它们取出来进行发布
// 所以早期事件的发布时间节点是早于其他事件的
Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;
// 早期事件广播器是一个Set<ApplicationEvent>集合,保存了无法发布的早期事件,当SimpleApplicationEventMulticaster
// 创建完之后随即进行发布,同事也要将其保存的事件释放
this.earlyApplicationEvents = null;
if (earlyEventsToProcess != null) {
for (ApplicationEvent earlyEvent : earlyEventsToProcess) {
getApplicationEventMulticaster().multicastEvent(earlyEvent);
}
}
}
11、初始化其他的单例Bean(非延迟加载的)
protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {
// Initialize conversion service for this context.
// 判断有无ConversionService(bean属性类型转换服务接口),并初始化
if (beanFactory.containsBean(CONVERSION_SERVICE_BEAN_NAME)
&& beanFactory.isTypeMatch(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class)) {
beanFactory.setConversionService(beanFactory.getBean(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class));
}
//
// Register a default embedded value resolver if no bean post-processor
// (such as a PropertyPlaceholderConfigurer bean) registered any before:
// at this point, primarily for resolution in annotation attribute values.
// 如果beanFactory中不包含EmbeddedValueResolver,则向其中添加一个EmbeddedValueResolver
// EmbeddedValueResolver-->解析bean中的占位符和表达式
if (!beanFactory.hasEmbeddedValueResolver()) {
beanFactory.addEmbeddedValueResolver(strVal -> getEnvironment().resolvePlaceholders(strVal));
}
// Initialize LoadTimeWeaverAware beans early to allow for registering their transformers early.
// 初始化LoadTimeWeaverAware类型的bean
// LoadTimeWeaverAware-->加载Spring Bean时织入第三方模块,如AspectJ
String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false);
for (String weaverAwareName : weaverAwareNames) {
getBean(weaverAwareName);
}
// Stop using the temporary ClassLoader for type matching.
// 释放临时类加载器
beanFactory.setTempClassLoader(null);
// Allow for caching all bean definition metadata, not expecting further changes.
// 冻结缓存的BeanDefinition元数据
beanFactory.freezeConfiguration();
// Instantiate all remaining (non-lazy-init) singletons.
// 初始化其他的非延迟加载的单例bean
beanFactory.preInstantiateSingletons();
}
12、完成刷新过程,通知生命周期处理器lifecycleProcessor刷新过程,同时发出ContextRefreshEvent通知
protected void finishRefresh() {
// Clear context-level resource caches (such as ASM metadata from scanning).
// 清空资源缓存
clearResourceCaches();
// Initialize lifecycle processor for this context.
// 初始化生命周期处理器
initLifecycleProcessor();
// Propagate refresh to lifecycle processor first.
// 调用生命周期处理器的onRefresh方法
getLifecycleProcessor().onRefresh();
// Publish the final event.
// 推送容器刷新事件
publishEvent(new ContextRefreshedEvent(this));
// Participate in LiveBeansView MBean, if active.
// MBean...没弄明白
LiveBeansView.registerApplicationContext(this);
}
