Spring源码：refresh方法解析
前言
在Spring中，refresh方法起着至关重要的作用，也是阅读源码的最合适的入口。它能够帮助Spring完成beanFactory的创建和记载、bean的加载、以及后置处理器的注册等功能。这个方法包括了整个Spring的执行流程和bean的完整生命周期。首先从new ClassPathXmlApplicationContext(“xxx.xml”)开始。
public ClassPathXmlApplicationContext(
String[] configLocations, boolean refresh, @Nullable ApplicationContext parent)
throws BeansException {
super(parent);
// 设置资源路径（"xxx.xml"）
setConfigLocations(configLocations);
if (refresh) {
// 直接调用refresh
refresh();
}
}
refresh方法中层次和逻辑非常清楚，而且包含了ApplicationContext的所有功能。从bean工厂的创建到bean对象的实例化和初始化再到完成Spring容器完成加载，都能在这里找到源码。
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// Prepare this context for refreshing.
// 初始化前的准备工作，主要是一些系统属性、环境变量的校验，比如Spring启动需要某些环境变量，可以在这个地方进行设置和校验
prepareRefresh();
// Tell the subclass to refresh the internal bean factory.
// 获取bean工厂，ConfigurableListableBeanFactory是默认的容器，在这一步会完成工厂的创建以及beanDefinition的读取
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// Prepare the bean factory for use in this context.
// 进入prepareBeanFactory前spring以及完成了对配置的解析，Spring的拓展从这里开始
prepareBeanFactory(beanFactory);
try {
// Allows post-processing of the bean factory in context subclasses.
// 留给子类覆盖做拓展，这里一般不做任何处理
postProcessBeanFactory(beanFactory);
// Invoke factory processors registered as beans in the context.
// 调用所有的BeanFactoryPostProcessors，将结果存入参数beanFactory中
invokeBeanFactoryPostProcessors(beanFactory);
// Register bean processors that intercept bean creation.
// 注册BeanPostProcessors，这里只是注册，真正的调用是在doGetBean中
registerBeanPostProcessors(beanFactory);
// Initialize message source for this context.
// 初始化消息原，比如国际化
initMessageSource();
// Initialize event multicaster for this context.
// 初始化消息广播器
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
// 留给子类类初始化其他的bean
onRefresh();
// Check for listener beans and register them.
// 注册监听器
registerListeners();
// Instantiate all remaining (non-lazy-init) singletons.
// 初始化剩下的单例bean，在这里才开始真正的对bean进行实例化和初始化
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.
// 完成刷新，通知生命周期处理器刷新过程。
finishRefresh();
}
}
}
1.prepareRefresh()，Spring初始化前的一些准备工作，主要是一些系统属性、环境变量的校验。设置Spring的活跃状态为以及开始时间。
2.obtainFreshBeanFactory()，初始化bean工厂，其返回的ConfigurableListableBeanFactory内部其实新建了一个DefaultListableBeanFactory(Spring默认的容器，是Spring中功能最完整、最成熟的容器)，并设置DefaultListableBeanFactory为全局变量。读取资源文件加载beanDefinition存入容器。
主要的代码是在refreshBeanFactory中，在refreshBeanFactory方法中Spring会new一个DefaultListableBeanFactory 对象，DefaultListableBeanFactory 是Spring中默认的BeanFactory，接着对这个beanFactory进行定制化处理，调用XmlBeanDefinition的loadBeanDefinitions方法从xml文件中加载所有的beanDefinition并加载到这个DefaultListableBeanFactory 中。而这个this.beanFactory = beanFactory则是将该DefaultListableBeanFactory 设置为全局变量，变成整个Spring容器默认的beanFactory。
protected final void refreshBeanFactory() throws BeansException {
// 判断是否以及存在BeanFactory，如果已经存在就销毁
if (hasBeanFactory()) {
destroyBeans();
closeBeanFactory();
}
try {
// 创建一个DefaultListableBeanFactory(Spring容器的基础，成熟、功能完善的容器)
DefaultListableBeanFactory beanFactory = createBeanFactory();
// 序列化id
beanFactory.setSerializationId(getId());
// 定制beanFactory
customizeBeanFactory(beanFactory);
loadBeanDefinitions(beanFactory);
this.beanFactory = beanFactory;
}
catch (IOException ex) {
throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex);
}
}
3.prepareBeanFactory(beanFactory)，初始化beanFactory，为beanFactory设置属性，比如添加属性编辑器、对SPEL表达式的支持、Aware回调接口的处理器、忽略的依赖和注册依赖。
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
// Tell the internal bean factory to use the context's class loader etc.
// 设置类加载器
beanFactory.setBeanClassLoader(getClassLoader());
// 设置对表达式的支持
beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
// 设置属性编辑器的支持
beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));
// Configure the bean factory with context callbacks.
// 添加回调接口的支持
beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
// 如果是EnvironmentAware、EmbeddedValueResolverAware等接口的实现类，就不进行自动装配
// 这些回调接口会通过实现类的setter将自身的一些属性注入
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.
// Spring检测到一下接口的实现类时便会将其注入
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.
// 添加监听器
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));
// Detect a LoadTimeWeaver and prepare for weaving, if found.
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.
// 设置环境变量
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(beanFactory)，留给子类覆盖做拓展，这里一般不做任何处理
5.invokeBeanFactoryPostProcessors(beanFactory)，调用所有的BeanFactoryPostProcessors，将结果存入参数beanFactory中。
public static void invokeBeanFactoryPostProcessors(
ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {
// Invoke BeanDefinitionRegistryPostProcessors first, if any.
Set<String> processedBeans = new HashSet<>();
// 传进来的beanFactory之前新建的DefaultListableBeanFactory，实现了BeanDefinitionRegistry接口，判断为true
if (beanFactory instanceof BeanDefinitionRegistry) {
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
// 存放BeanFactoryPostProcessor的容器
List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();
// 存放BeanDefinitionRegistryPostProcessor的容器
List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();
// 遍历作为参数传进来的beanFactoryPostProcessors
for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
// 优先调用BeanDefinitionRegistryPostProcessor，并区分开BeanFactoryPostProcessor和BeanDefinitionRegistryPostProcessor
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
BeanDefinitionRegistryPostProcessor registryProcessor =
(BeanDefinitionRegistryPostProcessor) postProcessor;
// 如果是BeanDefinitionRegistryPostProcessor，直接调用postProcessBeanDefinitionRegistry方法
registryProcessor.postProcessBeanDefinitionRegistry(registry);
// 存入集合
registryProcessors.add(registryProcessor);
}
else {
// 普通的BeanFactoryPostProcessor集合
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.k
// 下面是开始寻找Spring上下文中的BeanDefinitionRegistryPostProcessor
// 存放BeanDefinitionRegistryPostProcessor的集合
List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>();
// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
/**
* 首先处理的是BeanDefinitionRegistryPostProcessor
* 1.拿到所有的首先处理的是BeanDefinitionRegistryPostProcessor的beanName
* 2.如果BeanDefinitionRegistryPostProcessor实现了PriorityOrdered接口，就添加到currentRegistryProcessors集合中
* 3.调用invokeBeanDefinitionRegistryPostProcessors，将结果注册到registry(Spring默认的容器DefaultListableBeanFactory中)
* 4.清理空集合，加载调用实现 Ordered的BeanDefinitionRegistryPostProcessor
* 5.清理空集合，加载其他BeanDefinitionRegistryPostProcessor
*/
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);
// 排完序后将所有的BeanDefinitionRegistryPostProcessor注册
registryProcessors.addAll(currentRegistryProcessors);
// 调用
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
// 清除容器
currentRegistryProcessors.clear();
// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
// 调用实现 Ordered 的 BeanDefinitionRegistryPostProcessors，方法和上面差不多
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);
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
// Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear.
// 循环调用其他的BeanDefinitionRegistryPostProcessors，直到调用完毕
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;
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
}
// Now, invoke the postProcessBeanFactory callback of all processors handled so far.
invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
}
else {
// 下面处理非BeanDefinitionRegistry的处理器
// 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!
// 拿到所有的BeanFactoryPostProcessor的beanName
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
// Separate between BeanFactoryPostProcessors that implement PriorityOrdered,
// Ordered, and the rest.
// 将实现了Ordered、PriorityOrdered接口的、其他的BeanFactoryPostProcessors放在不同容器
List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
List<String> orderedPostProcessorNames = new ArrayList<>();
List<String> nonOrderedPostProcessorNames = new ArrayList<>();
// 遍历beanName，区分不同的BeanFactoryPostProcessors，放在不同的容器
for (String ppName : postProcessorNames) {
if (processedBeans.contains(ppName)) {
// skip - already processed in first phase above
}
else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessorNames.add(ppName);
}
else {
nonOrderedPostProcessorNames.add(ppName);
}
}
// First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.
// 首先调用实现了PriorityOrdered接口的BeanFactoryPostProcessors
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);
// Next, invoke the BeanFactoryPostProcessors that implement Ordered.
// 接着调用实现了BeanFactoryPostProcessors
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.
// 最后再调用其他的处理器
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...
// 清除缓存
beanFactory.clearMetadataCache();
}
在这个方法中主要做三件事：
(1)加载入参的beanFactoryPostProcessors
优先加载BeanDefinitionRegistryPostProcessor类型的，并且会直接调用一次registryProcessor.postProcessBeanDefinitionRegistry(registry)方法，然后分别将BeanDefinitionRegistryPostProcessor类型的和BeanFactoryPostProcessor放入不同类型的容器中。
(2)加载上下文的BeanDefinitionRegistryPostProcessor。
* 1.拿到所有的首先处理的是BeanDefinitionRegistryPostProcessor的beanName
* 2.如果BeanDefinitionRegistryPostProcessor实现了PriorityOrdered接口，就添加到currentRegistryProcessors集合中
* 3.调用invokeBeanDefinitionRegistryPostProcessors，将结果注册到registry(Spring默认的容器DefaultListableBeanFactory中)
* 4.清理空集合，加载调用实现 Ordered的BeanDefinitionRegistryPostProcessor
* 5.清理空集合，加载其他BeanDefinitionRegistryPostProcessor
(3)加载上下文的BeanFactoryPostProcessor
和第二步顺序一样也是按照PriorityOrdered、Ordered、和其他的BeanFactoryPostProcessor的顺序加载。
6.registerBeanPostProcessors(beanFactory)，注册BeanPostProcessors，和调用BeanFactoryPostProcessor的步骤差差不多。不过invokeBeanFactoryPostProcessors会调用后置处理器的方法，而这个仅仅是注册而已，不会调用其中的方法。
final class PostProcessorRegistrationDelegate {
public static void invokeBeanFactoryPostProcessors(
ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {
// Invoke BeanDefinitionRegistryPostProcessors first, if any.
Set<String> processedBeans = new HashSet<>();
// 传进来的beanFactory之前新建的DefaultListableBeanFactory，实现了BeanDefinitionRegistry接口，判断为true
if (beanFactory instanceof BeanDefinitionRegistry) {
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
// 存放BeanFactoryPostProcessor的容器
List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();
// 存放BeanDefinitionRegistryPostProcessor的容器
List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();
// 遍历作为参数传进来的beanFactoryPostProcessors
for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
// 优先调用BeanDefinitionRegistryPostProcessor，并区分开BeanFactoryPostProcessor和BeanDefinitionRegistryPostProcessor
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
BeanDefinitionRegistryPostProcessor registryProcessor =
(BeanDefinitionRegistryPostProcessor) postProcessor;
// 如果是BeanDefinitionRegistryPostProcessor，直接调用postProcessBeanDefinitionRegistry方法
registryProcessor.postProcessBeanDefinitionRegistry(registry);
// 存入集合
registryProcessors.add(registryProcessor);
}
else {
// 普通的BeanFactoryPostProcessor集合
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.k
// 下面是开始寻找Spring上下文中的BeanDefinitionRegistryPostProcessor
// 存放BeanDefinitionRegistryPostProcessor的集合
List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>();
// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
/**
* 首先处理的是BeanDefinitionRegistryPostProcessor
* 1.拿到所有的首先处理的是BeanDefinitionRegistryPostProcessor的beanName
* 2.如果BeanDefinitionRegistryPostProcessor实现了PriorityOrdered接口，就添加到currentRegistryProcessors集合中
* 3.调用invokeBeanDefinitionRegistryPostProcessors，将结果注册到registry(Spring默认的容器DefaultListableBeanFactory中)
* 4.清理空集合，加载调用实现 Ordered的BeanDefinitionRegistryPostProcessor
* 5.清理空集合，加载其他BeanDefinitionRegistryPostProcessor
*/
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);
// 排完序后将所有的BeanDefinitionRegistryPostProcessor注册
registryProcessors.addAll(currentRegistryProcessors);
// 调用
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
// 清除容器
currentRegistryProcessors.clear();
// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
// 调用实现 Ordered 的 BeanDefinitionRegistryPostProcessors，方法和上面差不多
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);
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
// Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear.
// 循环调用其他的BeanDefinitionRegistryPostProcessors，直到调用完毕
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;
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
}
// Now, invoke the postProcessBeanFactory callback of all processors handled so far.
invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
}
else {
// 下面处理非BeanDefinitionRegistry的处理器
// 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!
// 拿到所有的BeanFactoryPostProcessor的beanName
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
// Separate between BeanFactoryPostProcessors that implement PriorityOrdered,
// Ordered, and the rest.
// 将实现了Ordered、PriorityOrdered接口的、其他的BeanFactoryPostProcessors放在不同容器
List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
List<String> orderedPostProcessorNames = new ArrayList<>();
List<String> nonOrderedPostProcessorNames = new ArrayList<>();
// 遍历beanName，区分不同的BeanFactoryPostProcessors，放在不同的容器
for (String ppName : postProcessorNames) {
if (processedBeans.contains(ppName)) {
// skip - already processed in first phase above
}
else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessorNames.add(ppName);
}
else {
nonOrderedPostProcessorNames.add(ppName);
}
}
// First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.
// 首先调用实现了PriorityOrdered接口的BeanFactoryPostProcessors
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);
// Next, invoke the BeanFactoryPostProcessors that implement Ordered.
// 接着调用实现了BeanFactoryPostProcessors
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.
// 最后再调用其他的处理器
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...
// 清楚缓存
beanFactory.clearMetadataCache();
}
public static void registerBeanPostProcessors(
ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
// 获取所有postProcessor的名称
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 BeanPostProcessorChecker，它会在 BeanPostProcessor 实例化期间创建 bean 时记录一条信息消息，即当 bean 不符合所有 BeanPostProcessor 处理的条件时。
int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));
// Separate between BeanPostProcessors that implement PriorityOrdered,
// Ordered, and the rest.
// 创建不同的集合来区分实现了PriorityOrdered、Ordered和其他BeanPostProcessors
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);
// 注册MergedBeanDefinitionPostProcessor类型的
if (pp instanceof MergedBeanDefinitionPostProcessor) {
internalPostProcessors.add(pp);
}
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
// 实现了Ordered接口
orderedPostProcessorNames.add(ppName);
}
else {
// 普通的BeanPostProcessor
nonOrderedPostProcessorNames.add(ppName);
}
}
// First, register the BeanPostProcessors that implement PriorityOrdered.
// 注册实现了PriorityOrdered接口的BeanPostProcessors
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);
// Next, register the BeanPostProcessors that implement Ordered.
// 注册实现了Ordered接口的BeanPostProcessors
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.
// 注册普通的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.
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).
// 添加应用监听器
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}
7.initMessageSource()，初始化Message源，对不同语言的消息体进行国际化处理。
8.initApplicationEventMulticaster()，初始化消息广播器
9.onRefresh()，留给子类初始化其他的bean
10.registerListeners()，注册监听器
11.finishBeanFactoryInitialization(beanFactory)，这个方法也是重点，Spring就是在这里完成非懒加载的单例bean的加载的。其中bean的加载和初始化就是在preInstantiateSingletons中，如果getBean的结果为null，Spring就会通过beanName在工厂中拿到对应的beaDefinition，开始加载bean。
public void preInstantiateSingletons() throws BeansException {
if (logger.isDebugEnabled()) {
logger.debug("Pre-instantiating singletons in " + this);
}
// Iterate over a copy to allow for init methods which in turn register new bean definitions.
// While this may not be part of the regular factory bootstrap, it does otherwise work fine.
// 获取所有的beanName
List<String> beanNames = new ArrayList<>(this.beanDefinitionNames);
// Trigger initialization of all non-lazy singleton beans...
// 遍历BeanName
for (String beanName : beanNames) {
RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);
// 如果BeanDefinition符合单例、非懒加载、非抽象的类，就开始加载bean
if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) {
if (isFactoryBean(beanName)) {
// 获取bean
Object bean = getBean(FACTORY_BEAN_PREFIX + beanName);
// FactoryBean是特殊的bean，需要特殊处理。FactoryBean是通过getObject方法获取真正的对象
if (bean instanceof FactoryBean) {
FactoryBean<?> factory = (FactoryBean<?>) bean;
boolean isEagerInit;
if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {
isEagerInit = AccessController.doPrivileged(
(PrivilegedAction<Boolean>) ((SmartFactoryBean<?>) factory)::isEagerInit,
getAccessControlContext());
}
else {
isEagerInit = (factory instanceof SmartFactoryBean &&
((SmartFactoryBean<?>) factory).isEagerInit());
}
if (isEagerInit) {
getBean(beanName);
}
}
}
else {
// 获取bean
getBean(beanName);
}
}
}
// Trigger post-initialization callback for all applicable beans...
// 触发所有bean的回调
for (String beanName : beanNames) {
Object singletonInstance = getSingleton(beanName);
if (singletonInstance instanceof SmartInitializingSingleton) {
SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton) singletonInstance;
if (System.getSecurityManager() != null) {
AccessController.doPrivileged((PrivilegedAction<Object>) () -> {
smartSingleton.afterSingletonsInstantiated();
return null;
}, getAccessControlContext());
}
else {
smartSingleton.afterSingletonsInstantiated();
}
}
}
}
12finishRefresh()，完成refresh方法，通知生命周期处理器刷新过程，并发出广播通知别人。