Spring初始化源码分析
接下来我们详细分析下refresh方法的作用。
一、refresh方法
代码语言：javascript复制 @Override
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// 1.context 为刷新做准备
// Prepare this context for refreshing.
prepareRefresh();
// Tell the subclass to refresh the internal bean factory.
// 2.让子类实现刷新内部持有BeanFactory
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// Prepare the bean factory for use in this context.
// 3.对beanFactory做一些准备工作：注册一些context回调、bean等
prepareBeanFactory(beanFactory);
try {
// Allows post-processing of the bean factory in context subclasses.
// 4.调用留给子类来提供实现逻辑的 对BeanFactory进行处理的钩子方法
postProcessBeanFactory(beanFactory);
// Invoke factory processors registered as beans in the context.
// 5.执行context中注册的 BeanFactoryPostProcessor bean
invokeBeanFactoryPostProcessors(beanFactory);
// Register bean processors that intercept bean creation.
// 6.注册BeanPostProcessor: 获得用户注册的BeanPostProcessor实例，注册到BeanFactory上
registerBeanPostProcessors(beanFactory);
// Initialize message source for this context.
// 7.初始化国际化资源
initMessageSource();
// Initialize event multicaster for this context.
// 8.初始化Application event 广播器
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
// 9.执行 有子类来提供实现逻辑的钩子方法 onRefresh
onRefresh();
// Check for listener beans and register them.
// 10.注册ApplicationListener: 获得用户注册的ApplicationListener Bean实例，注册到广播器上
registerListeners();
// Instantiate all remaining (non-lazy-init) singletons.
// 11、完成剩余的单例Bean的实例化
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.
// 12 发布对应的事件
finishRefresh();
}
catch (BeansException ex) {
if (logger.isWarnEnabled()) {
logger.warn("Exception encountered during context initialization - "
"cancelling refresh attempt: " ex);
}
// Destroy already created singletons to avoid dangling resources.
destroyBeans();
// Reset 'active' flag.
cancelRefresh(ex);
// Propagate exception to caller.
throw ex;
}
finally {
// Reset common introspection caches in Spring's core, since we
// might not ever need metadata for singleton beans anymore...
resetCommonCaches();
}
}
}二、prepareRefresh
完成一些刷新前的准备工作.
代码语言：javascript复制 protected void prepareRefresh() {
// Switch to active.
this.startupDate = System.currentTimeMillis();
// 设置相关的状态
this.closed.set(false);
this.active.set(true);
if (logger.isDebugEnabled()) {
if (logger.isTraceEnabled()) {
logger.trace("Refreshing " this);
}
else {
logger.debug("Refreshing " getDisplayName());
}
}
// Initialize any placeholder property sources in the context environment.
initPropertySources();
// Validate that all properties marked as required are resolvable:
// see ConfigurablePropertyResolver#setRequiredProperties
getEnvironment().validateRequiredProperties();
// Store pre-refresh ApplicationListeners...
if (this.earlyApplicationListeners == null) {
this.earlyApplicationListeners = new LinkedHashSet<>(this.applicationListeners);
}
else {
// Reset local application listeners to pre-refresh state.
this.applicationListeners.clear();
this.applicationListeners.addAll(this.earlyApplicationListeners);
}
// Allow for the collection of early ApplicationEvents,
// to be published once the multicaster is available...
this.earlyApplicationEvents = new LinkedHashSet<>();
}三、obtainFreshBeanFactory
在obtainFreshBeanFactory方法会完成BeanFactory对象的创建。
代码语言：javascript复制 protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
// 刷新容器
refreshBeanFactory();
return getBeanFactory();
}如果是基于XML的方式使用会在refreshBeanFactory中完成配置文件的加载解析操作
代码语言：javascript复制 @Override
protected final void refreshBeanFactory() throws BeansException {
if (hasBeanFactory()) {
// 销毁前面的 BeanFactory
destroyBeans();
closeBeanFactory();
}
try {
// 创建 BeanFactory 对象
DefaultListableBeanFactory beanFactory = createBeanFactory();
beanFactory.setSerializationId(getId());
customizeBeanFactory(beanFactory);
loadBeanDefinitions(beanFactory); // 加载解析配置文件
this.beanFactory = beanFactory;
}
catch (IOException ex) {
throw new ApplicationContextException("I/O error parsing bean definition source for " getDisplayName(), ex);
}
}四、prepareBeanFactory
上面的obtainFreshBeanFactory中完成了BeanFactory的创建和相关BeanDefinition对象的组装，然后在接下来的prepareBeanFactory中会完成相关的准备工作。
代码语言：javascript复制 protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
// Tell the internal bean factory to use the context's class loader etc.
// 设置beanFactory的classloader为当前context的classloader
beanFactory.setBeanClassLoader(getClassLoader());
// 设置beanfactory的表达式语言处理器
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类
beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));
// Configure the bean factory with context callbacks.
// 添加beanPostProcessor,ApplicationContextAwareProcessor此类用来完成某些Aware对象的注入
beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
// 设置要忽略自动装配的接口，很多同学理解不了为什么此处要对这些接口进行忽略，原因非常简单，这些接口的实现是由容器通过set方法进行注入的，
// 所以在使用autowire进行注入的时候需要将这些接口进行忽略
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,当在进行ioc初始化的如果有多个实现，那么就使用指定的对象进行注入
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.
// 注册BPP
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));
// Detect a LoadTimeWeaver and prepare for weaving, if found.
// 增加对AspectJ的支持，在java中织入分为三种方式，分为编译器织入，类加载器织入，运行期织入，编译器织入是指在java编译器，采用特殊的编译器，将切面织入到java类中，
// 而类加载期织入则指通过特殊的类加载器，在类字节码加载到JVM时，织入切面，运行期织入则是采用cglib和jdk进行切面的织入
// aspectj提供了两种织入方式，第一种是通过特殊编译器，在编译器，将aspectj语言编写的切面类织入到java类中，第二种是类加载期织入，就是下面的load time weaving，此处后续讲
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到一级缓存中
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());
}
}五、postProcessBeanFactory
该方法是一个空方法，交给子类自己处理的方法
六、invokeBeanFactoryPostProcessors
invokeBeanFactoryPostProcessors是BeanFactory的后置处理方法。核心是会完成注册的BeanFactoryPostProcessor接口和BeanDefinitionRegistryPostProcessor的相关逻辑。invokeBeanFactoryPostProcessors是其核心的方法。
代码语言：javascript复制 public static void invokeBeanFactoryPostProcessors(
ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {
// Invoke BeanDefinitionRegistryPostProcessors first, if any.
// 无论是什么情况，优先执行BeanDefinitionRegistryPostProcessors
// 将已经执行过的BFPP存储在processedBeans中，防止重复执行
Set<String> processedBeans = new HashSet<>();
// 判断beanfactory是否是BeanDefinitionRegistry类型，此处是DefaultListableBeanFactory,实现了BeanDefinitionRegistry接口，所以为true
if (beanFactory instanceof BeanDefinitionRegistry) {
// 类型转换
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
// 此处希望大家做一个区分，两个接口是不同的，BeanDefinitionRegistryPostProcessor是BeanFactoryPostProcessor的子集
// BeanFactoryPostProcessor主要针对的操作对象是BeanFactory，而BeanDefinitionRegistryPostProcessor主要针对的操作对象是BeanDefinition
// 存放BeanFactoryPostProcessor的集合
List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();
// 存放BeanDefinitionRegistryPostProcessor的集合
List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();
// 首先处理入参中的beanFactoryPostProcessors,遍历所有的beanFactoryPostProcessors，将BeanDefinitionRegistryPostProcessor
// 和BeanFactoryPostProcessor区分开
for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
// 如果是BeanDefinitionRegistryPostProcessor
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
BeanDefinitionRegistryPostProcessor registryProcessor =
(BeanDefinitionRegistryPostProcessor) postProcessor;
// 直接执行BeanDefinitionRegistryPostProcessor接口中的postProcessBeanDefinitionRegistry方法
registryProcessor.postProcessBeanDefinitionRegistry(registry);
// 添加到registryProcessors，用于后续执行postProcessBeanFactory方法
registryProcessors.add(registryProcessor);
} else {
// 否则，只是普通的BeanFactoryPostProcessor，添加到regularPostProcessors，用于后续执行postProcessBeanFactory方法
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.
// 用于保存本次要执行的BeanDefinitionRegistryPostProcessor
List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>();
// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
// 调用所有实现PriorityOrdered接口的BeanDefinitionRegistryPostProcessor实现类
// 找到所有实现BeanDefinitionRegistryPostProcessor接口bean的beanName
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
// 遍历处理所有符合规则的postProcessorNames
for (String ppName : postProcessorNames) {
// 检测是否实现了PriorityOrdered接口
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
// 获取名字对应的bean实例，添加到currentRegistryProcessors中
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
// 将要被执行的BFPP名称添加到processedBeans，避免后续重复执行
processedBeans.add(ppName);
}
}
// 按照优先级进行排序操作
sortPostProcessors(currentRegistryProcessors, beanFactory);
// 添加到registryProcessors中，用于最后执行postProcessBeanFactory方法
registryProcessors.addAll(currentRegistryProcessors);
// 遍历currentRegistryProcessors，执行postProcessBeanDefinitionRegistry方法
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
// 执行完毕之后，清空currentRegistryProcessors
currentRegistryProcessors.clear();
// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
// 调用所有实现Ordered接口的BeanDefinitionRegistryPostProcessor实现类
// 找到所有实现BeanDefinitionRegistryPostProcessor接口bean的beanName，
// 此处需要重复查找的原因在于上面的执行过程中可能会新增其他的BeanDefinitionRegistryPostProcessor
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
// 检测是否实现了Ordered接口，并且还未执行过
if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {
// 获取名字对应的bean实例，添加到currentRegistryProcessors中
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
// 将要被执行的BFPP名称添加到processedBeans，避免后续重复执行
processedBeans.add(ppName);
}
}
// 按照优先级进行排序操作
sortPostProcessors(currentRegistryProcessors, beanFactory);
// 添加到registryProcessors中，用于最后执行postProcessBeanFactory方法
registryProcessors.addAll(currentRegistryProcessors);
// 遍历currentRegistryProcessors，执行postProcessBeanDefinitionRegistry方法
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
// 执行完毕之后，清空currentRegistryProcessors
currentRegistryProcessors.clear();
// Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear.
// 最后，调用所有剩下的BeanDefinitionRegistryPostProcessors
boolean reiterate = true;
while (reiterate) {
reiterate = false;
// 找出所有实现BeanDefinitionRegistryPostProcessor接口的类
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
// 遍历执行
for (String ppName : postProcessorNames) {
// 跳过已经执行过的BeanDefinitionRegistryPostProcessor
if (!processedBeans.contains(ppName)) {
// 获取名字对应的bean实例，添加到currentRegistryProcessors中
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
// 将要被执行的BFPP名称添加到processedBeans，避免后续重复执行
processedBeans.add(ppName);
reiterate = true;
}
}
// 按照优先级进行排序操作
sortPostProcessors(currentRegistryProcessors, beanFactory);
// 添加到registryProcessors中，用于最后执行postProcessBeanFactory方法
registryProcessors.addAll(currentRegistryProcessors);
// 遍历currentRegistryProcessors，执行postProcessBeanDefinitionRegistry方法
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
// 执行完毕之后，清空currentRegistryProcessors
currentRegistryProcessors.clear();
}
// Now, invoke the postProcessBeanFactory callback of all processors handled so far.
// 调用所有BeanDefinitionRegistryPostProcessor的postProcessBeanFactory方法
invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
// 最后，调用入参beanFactoryPostProcessors中的普通BeanFactoryPostProcessor的postProcessBeanFactory方法
invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
} else {
// Invoke factory processors registered with the context instance.
// 如果beanFactory不归属于BeanDefinitionRegistry类型，那么直接执行postProcessBeanFactory方法
invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);
}
// 到这里为止，入参beanFactoryPostProcessors和容器中的所有BeanDefinitionRegistryPostProcessor已经全部处理完毕，下面开始处理容器中
// 所有的BeanFactoryPostProcessor
// 可能会包含一些实现类，只实现了BeanFactoryPostProcessor，并没有实现BeanDefinitionRegistryPostProcessor接口
// Do not initialize FactoryBeans here: We need to leave all regular beans
// uninitialized to let the bean factory post-processors apply to them!
// 找到所有实现BeanFactoryPostProcessor接口的类
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
// Separate between BeanFactoryPostProcessors that implement PriorityOrdered,
// Ordered, and the rest.
// 用于存放实现了PriorityOrdered接口的BeanFactoryPostProcessor
List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
// 用于存放实现了Ordered接口的BeanFactoryPostProcessor的beanName
// List<String> orderedPostProcessorNames = new ArrayList<>();
List<BeanFactoryPostProcessor> orderedPostProcessor = new ArrayList<>();
// 用于存放普通BeanFactoryPostProcessor的beanName
// List<String> nonOrderedPostProcessorNames = new ArrayList<>();
List<BeanFactoryPostProcessor> nonOrderedPostProcessorNames = new ArrayList<>();
// 遍历postProcessorNames,将BeanFactoryPostProcessor按实现PriorityOrdered、实现Ordered接口、普通三种区分开
for (String ppName : postProcessorNames) {
// 跳过已经执行过的BeanFactoryPostProcessor
if (processedBeans.contains(ppName)) {
// skip - already processed in first phase above
}
// 添加实现了PriorityOrdered接口的BeanFactoryPostProcessor到priorityOrderedPostProcessors
else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
}
// 添加实现了Ordered接口的BeanFactoryPostProcessor的beanName到orderedPostProcessorNames
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
// orderedPostProcessorNames.add(ppName);
orderedPostProcessor.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
} else {
// 添加剩下的普通BeanFactoryPostProcessor的beanName到nonOrderedPostProcessorNames
// nonOrderedPostProcessorNames.add(ppName);
nonOrderedPostProcessorNames.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
}
}
// First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.
// 对实现了PriorityOrdered接口的BeanFactoryPostProcessor进行排序
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
// 遍历实现了PriorityOrdered接口的BeanFactoryPostProcessor，执行postProcessBeanFactory方法
invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);
// Next, invoke the BeanFactoryPostProcessors that implement Ordered.
// 创建存放实现了Ordered接口的BeanFactoryPostProcessor集合
// List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size());
// 遍历存放实现了Ordered接口的BeanFactoryPostProcessor名字的集合
// for (String postProcessorName : orderedPostProcessorNames) {
// 将实现了Ordered接口的BeanFactoryPostProcessor添加到集合中
// orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
// }
// 对实现了Ordered接口的BeanFactoryPostProcessor进行排序操作
// sortPostProcessors(orderedPostProcessors, beanFactory);
sortPostProcessors(orderedPostProcessor, beanFactory);
// 遍历实现了Ordered接口的BeanFactoryPostProcessor，执行postProcessBeanFactory方法
// invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(orderedPostProcessor, beanFactory);
// Finally, invoke all other BeanFactoryPostProcessors.
// 最后，创建存放普通的BeanFactoryPostProcessor的集合
// List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());
// 遍历存放实现了普通BeanFactoryPostProcessor名字的集合
// for (String postProcessorName : nonOrderedPostProcessorNames) {
// 将普通的BeanFactoryPostProcessor添加到集合中
// nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
// }
// 遍历普通的BeanFactoryPostProcessor，执行postProcessBeanFactory方法
// invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(nonOrderedPostProcessorNames, beanFactory);
// Clear cached merged bean definitions since the post-processors might have
// modified the original metadata, e.g. replacing placeholders in values...
// 清除元数据缓存（mergeBeanDefinitions、allBeanNamesByType、singletonBeanNameByType）
// 因为后置处理器可能已经修改了原始元数据，例如，替换值中的占位符
beanFactory.clearMetadataCache();
}要搞清楚上面的代码含义首先需要搞清楚出这两者之间的关系
实现的核心流程是
在这个位置核心的代表是 ConfigurationClassPostProcessor用来处理 @Configuration注解表示的Java类，来处理其中的@Bean,@Primary等注解。
七、registerBeanPostProcessors
完成Bean对象的相关后置处理器的注册。具体的代码逻辑和上面是差不多的。
代码语言：javascript复制 /**
* 注册beanPostProcessor
* @param beanFactory
* @param applicationContext
*/
public static void registerBeanPostProcessors(
ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
// 找到所有实现了BeanPostProcessor接口的类
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.
// 记录下BeanPostProcessor的目标计数
// 此处为什么要 1呢，原因非常简单，在此方法的最后会添加一个BeanPostProcessorChecker的类
int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() 1 postProcessorNames.length;
// 添加BeanPostProcessorChecker(主要用于记录信息)到beanFactory中
beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));
// Separate between BeanPostProcessors that implement PriorityOrdered,
// Ordered, and the rest.
// 定义存放实现了PriorityOrdered接口的BeanPostProcessor集合
List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
// 定义存放spring内部的BeanPostProcessor
List<BeanPostProcessor> internalPostProcessors = new ArrayList<>();
// 定义存放实现了Ordered接口的BeanPostProcessor的name集合
List<String> orderedPostProcessorNames = new ArrayList<>();
// 定义存放普通的BeanPostProcessor的name集合
List<String> nonOrderedPostProcessorNames = new ArrayList<>();
// 遍历beanFactory中存在的BeanPostProcessor的集合postProcessorNames，
for (String ppName : postProcessorNames) {
// 如果ppName对应的BeanPostProcessor实例实现了PriorityOrdered接口，则获取到ppName对应的BeanPostProcessor的实例添加到priorityOrderedPostProcessors中
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
priorityOrderedPostProcessors.add(pp);
// 如果ppName对应的BeanPostProcessor实例也实现了MergedBeanDefinitionPostProcessor接口，那么则将ppName对应的bean实例添加到internalPostProcessors中
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
// 如果ppName对应的BeanPostProcessor实例没有实现PriorityOrdered接口，但是实现了Ordered接口，那么将ppName对应的bean实例添加到orderedPostProcessorNames中
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessorNames.add(ppName);
} else {
// 否则将ppName添加到nonOrderedPostProcessorNames中
nonOrderedPostProcessorNames.add(ppName);
}
}
// First, register the BeanPostProcessors that implement PriorityOrdered.
// 首先，对实现了PriorityOrdered接口的BeanPostProcessor实例进行排序操作
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
// 注册实现了PriorityOrdered接口的BeanPostProcessor实例添加到beanFactory中
registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);
// Next, register the BeanPostProcessors that implement Ordered.
// 注册所有实现Ordered的beanPostProcessor
List<BeanPostProcessor> orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size());
for (String ppName : orderedPostProcessorNames) {
// 根据ppName找到对应的BeanPostProcessor实例对象
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
// 将实现了Ordered接口的BeanPostProcessor添加到orderedPostProcessors集合中
orderedPostProcessors.add(pp);
// 如果ppName对应的BeanPostProcessor实例也实现了MergedBeanDefinitionPostProcessor接口，那么则将ppName对应的bean实例添加到internalPostProcessors中
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
// 对实现了Ordered接口的BeanPostProcessor进行排序操作
sortPostProcessors(orderedPostProcessors, beanFactory);
// 注册实现了Ordered接口的BeanPostProcessor实例添加到beanFactory中
registerBeanPostProcessors(beanFactory, orderedPostProcessors);
// Now, register all regular BeanPostProcessors.
// 创建存放没有实现PriorityOrdered和Ordered接口的BeanPostProcessor的集合
List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());
// 遍历集合
for (String ppName : nonOrderedPostProcessorNames) {
// 根据ppName找到对应的BeanPostProcessor实例对象
BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
// 将没有实现PriorityOrdered和Ordered接口的BeanPostProcessor添加到nonOrderedPostProcessors集合中
nonOrderedPostProcessors.add(pp);
// 如果ppName对应的BeanPostProcessor实例也实现了MergedBeanDefinitionPostProcessor接口，那么则将ppName对应的bean实例添加到internalPostProcessors中
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
// 注册没有实现PriorityOrdered和Ordered的BeanPostProcessor实例添加到beanFactory中
registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);
// Finally, re-register all internal BeanPostProcessors.
// 将所有实现了MergedBeanDefinitionPostProcessor类型的BeanPostProcessor进行排序操作
sortPostProcessors(internalPostProcessors, beanFactory);
// 注册所有实现了MergedBeanDefinitionPostProcessor类型的BeanPostProcessor到beanFactory中
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ApplicationListenerDetector到beanFactory中
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}八、initMessageSource
为上下文初始化message源，即不同语言的消息体，国际化处理.此处不过多介绍、
九、initApplicationEventMulticaster
initApplicationEventMulticaster初始化事件监听多路广播器.
代码语言：javascript复制 protected void initApplicationEventMulticaster() {
// 获取当前bean工厂,一般是DefaultListableBeanFactory
ConfigurableListableBeanFactory beanFactory = getBeanFactory();
// 判断容器中是否存在bdName为applicationEventMulticaster的bd，也就是说自定义的事件监听多路广播器，必须实现ApplicationEventMulticaster接口
if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
// 如果有，则从bean工厂得到这个bean对象
this.applicationEventMulticaster =
beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
if (logger.isTraceEnabled()) {
logger.trace("Using ApplicationEventMulticaster [" this.applicationEventMulticaster "]");
}
}
else {
// 如果没有，则默认采用SimpleApplicationEventMulticaster
this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
if (logger.isTraceEnabled()) {
logger.trace("No '" APPLICATION_EVENT_MULTICASTER_BEAN_NAME "' bean, using "
"[" this.applicationEventMulticaster.getClass().getSimpleName() "]");
}
}
}代码很简单，创建了一个SimpleApplicationEventMulticaster对象，来广播相关的消息事件。
十、onRefresh
留给子类来初始化其他的bean
十一、registerListeners
所有注册的bean中查找listener bean,注册到消息广播器中.
代码语言：javascript复制 protected void registerListeners() {
// Register statically specified listeners first.
// 遍历应用程序中存在的监听器集合，并将对应的监听器添加到监听器的多路广播器中
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!
// 从容器中获取所有实现了ApplicationListener接口的bd的bdName
// 放入ApplicationListenerBeans集合中
String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);
for (String listenerBeanName : listenerBeanNames) {
getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);
// getApplicationEventMulticaster().addApplicationListener(this.getBean(listenerBeanName,ApplicationListener.class));
}
// Publish early application events now that we finally have a multicaster...
// 此处先发布早期的监听器集合
Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;
this.earlyApplicationEvents = null;
if (!CollectionUtils.isEmpty(earlyEventsToProcess)) {
for (ApplicationEvent earlyEvent : earlyEventsToProcess) {
getApplicationEventMulticaster().multicastEvent(earlyEvent);
}
}
}十二、finishBeanFactoryInitialization
finishBeanFactoryInitialization初始化剩下的单实例（非懒加载的）.这个专门单独讲解
十三、finishRefresh
finishRefresh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通知别人.
代码语言：javascript复制 protected void finishRefresh() {
// Clear context-level resource caches (such as ASM metadata from scanning).
// 清除上下文级别的资源缓存(如扫描的ASM元数据)
// 清空在资源加载器中的所有资源缓存
clearResourceCaches();
// Initialize lifecycle processor for this context.
// 为这个上下文初始化生命周期处理器
// 初始化LifecycleProcessor.如果上下文中找到'lifecycleProcessor'的LifecycleProcessor Bean对象，
// 则使用DefaultLifecycleProcessor
initLifecycleProcessor();
// Propagate refresh to lifecycle processor first.
// 首先将刷新传播到生命周期处理器
// 上下文刷新的通知，例如自动启动的组件
getLifecycleProcessor().onRefresh();
// Publish the final event.
// 发布最终事件
// 新建ContextRefreshedEvent事件对象，将其发布到所有监听器。
publishEvent(new ContextRefreshedEvent(this));
// Participate in LiveBeansView MBean, if active.
// 参与LiveBeansView MBean，如果是活动的
// LiveBeansView:Sping用于支持JMX 服务的类
// 注册当前上下文到LiveBeansView，以支持JMX服务
LiveBeansView.registerApplicationContext(this);
}
