Spingboot启动的refreshContext(context)
...大约 16 分钟
Spingboot启动的refreshContext(context)
入口
private void refreshContext(ConfigurableApplicationContext context) {
refresh((ApplicationContext) context);
if (this.registerShutdownHook) {
try {
context.registerShutdownHook();
}
catch (AccessControlException ex) {
// Not allowed in some environments.
}
}
}
进入refresh((ApplicationContext) context);
/**
* Refresh the underlying {@link ApplicationContext}.
* @param applicationContext the application context to refresh
* @deprecated since 2.3.0 in favor of
* {@link #refresh(ConfigurableApplicationContext)}
*/
@Deprecated
protected void refresh(ApplicationContext applicationContext) {
Assert.isInstanceOf(ConfigurableApplicationContext.class, applicationContext);
refresh((ConfigurableApplicationContext) applicationContext);
}
进入refresh((ConfigurableApplicationContext) applicationContext);
/**
* Refresh the underlying {@link ApplicationContext}.
* @param applicationContext the application context to refresh
*/
protected void refresh(ConfigurableApplicationContext applicationContext) {
applicationContext.refresh();
}
// 进入来到接口层，去到 ServletWebServerApplicationContext 的实现类
@Override
public final void refresh() throws BeansException, IllegalStateException {
try {
super.refresh();
}
catch (RuntimeException ex) {
WebServer webServer = this.webServer;
if (webServer != null) {
webServer.stop();
}
throw ex;
}
}
// 调用父类的 refresh()
子类实现调用父类的 refresh()
@Override
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// 1. Prepare this context for refreshing.
prepareRefresh();
// 2. Tell the subclass to refresh the internal bean factory.
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// 3. Prepare the bean factory for use in this context.
prepareBeanFactory(beanFactory);
try {
// 4. Allows post-processing of the bean factory in context subclasses.
postProcessBeanFactory(beanFactory);
// 5. Invoke factory processors registered as beans in the context.
invokeBeanFactoryPostProcessors(beanFactory);
// 6. Register bean processors that intercept bean creation.
registerBeanPostProcessors(beanFactory);
// 7. Initialize message source for this context.
initMessageSource();
// 8. Initialize event multicaster for this context.
initApplicationEventMulticaster();
// 9. Initialize other special beans in specific context subclasses.
onRefresh();
// 10. Check for listener beans and register them.
registerListeners();
// 11. Instantiate all remaining (non-lazy-init) singletons.
finishBeanFactoryInitialization(beanFactory);
// 12. Last step: publish corresponding event.
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();
}
}
}
逐个描述refresh()12步
上面代码梳理已经找到refresh的源码位置，下面逐个描述。
第1步：prepareRefresh();
repare this context for refreshing. 准备此上下文以进行刷新
protected void prepareRefresh() {
// 清除本地元数据缓存（如果有），删除所有缓存的类元数据。
this.scanner.clearCache();
// 调用父类，写在下面
super.prepareRefresh();
}
/**
* Prepare this context for refreshing, setting its startup date and
* active flag as well as performing any initialization of property sources.
* 准备此上下文以进行刷新、设置其启动日期和活动标志以及执行所有属性源的初始化。
*/
protected void prepareRefresh() {
// Switch to active.
this.startupDate = System.currentTimeMillis();
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.
// 初始化上下文环境中的所有占位符属性源。
initPropertySources();
// Validate that all properties marked as required are resolvable:
// see ConfigurablePropertyResolver#setRequiredProperties
// 验证标记为必需的所有属性都是可解析的
getEnvironment().validateRequiredProperties();
// Store pre-refresh ApplicationListeners...
// 存储预刷新 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...
// 允许收集早期的应用程序事件，一旦多播器可用就发布
this.earlyApplicationEvents = new LinkedHashSet<>();
}
第2步：ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
Tell the subclass to refresh the internal bean factory. 告诉子类刷新内部 bean 工厂，得到Bean工厂
protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {
refreshBeanFactory();
// 返回BeanFactory
return getBeanFactory();
}
protected final void refreshBeanFactory() throws IllegalStateException {
// 如果当前值 refreshed 是预期值 false，则自动将值设置为给定的true 更新值
if (!this.refreshed.compareAndSet(false, true)) {
throw new IllegalStateException(
"GenericApplicationContext does not support multiple refresh attempts: just call 'refresh' once");
}
// getId():applicton
// 指定一个 id 用于序列化目的，如果需要，允许将此 BeanFactory 从此 id 反序列化回 BeanFactory 对象。
this.beanFactory.setSerializationId(getId());
}
@Override
public final ConfigurableListableBeanFactory getBeanFactory() {
return this.beanFactory;
}
第3步：prepareBeanFactory(beanFactory);
Prepare the bean factory for use in this context. 准备 bean 工厂以在此上下文中使用
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
// Tell the internal bean factory to use the context's class loader etc.
// 告诉内部 bean 工厂使用上下文的类加载器等
beanFactory.setBeanClassLoader(getClassLoader());
beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));
// Configure the bean factory with context callbacks.
// 使用上下文回调配置 bean 工厂
beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
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.
// BeanFactory 接口未在普通工厂中注册为可解析类型
// MessageSource registered (and found for autowiring) as a bean.
// MessageSource 作为 bean 注册（并为自动装配找到）
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.
// 将用于检测内部 bean 的早期后处理器注册为 ApplicationListener
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));
// Detect a LoadTimeWeaver and prepare for weaving, if found.
// 检测 LoadTimeWeaver 并准备编织（如果找到）
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());
}
}
第4步：postProcessBeanFactory(beanFactory);
Allows post-processing of the bean factory in context subclasses. 调用在上下文中注册为 bean 的工厂处理器 实例化并调用所有已注册的 BeanFactoryPostProcessor bean，如果给定，则尊重显式顺序 这里创建的是AnnotationConfigServletWebServerApplicationContext类的上下文，所以执行的是这个类里的postProcessBeanFactory(beanFactory)方法
BeanFactoryPostProcessor是在spring容器加载了bean的定义文件之后，在bean实例化之前执行的。 接口方法的入参是ConfigurrableListableBeanFactory，使用该参数，可以获取到相关bean的定义信息BeanFactoryPostProcessor接口，可以在spring的bean创建之前，修改bean的定义属性。 也就是说，Spring允许BeanFactoryPostProcessor在容器实例化任何其它bean之前读取配置元数据，并可以根据需要进行修改。 例如:
- 可以把bean的scope从singleton改为prototype
- 也可以把property的值给修改掉。
- 可以同时配置多个BeanFactoryPostProcessor，并通过设置'order'属性来控制各个BeanFactoryPostProcessor的执行次序。
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {
// 调用父类，注册 Servlet 上下文感知处理器
super.postProcessBeanFactory(beanFactory);
if (this.basePackages != null && this.basePackages.length > 0) {
this.scanner.scan(this.basePackages);
}
if (!this.annotatedClasses.isEmpty()) {
this.reader.register(ClassUtils.toClassArray(this.annotatedClasses));
}
}
这里注册了3个
- SharedMetadataReaderFactoryContextInitializer$CachingetadataReaderFactoryPostProcessor 在definition的propertyValues中添加 metadataReaderFactory ：org.springframework.boot.autoconfigure.internalCachingMetadataReaderFactory 后add到regularPostProcessors
- ConfiguartionWarningsApplicationContextInitializer$ConfigurationWarningsPostProcessor 根据Checks打印Warn在日志里。后add到regularPostProcessors
- ConfigFileApplicationListener$PropertySourceOrderingPostProcessor 直接add到regularPostProcessors
scanner、reader的判断条件在启动时没有走到，在当前环境下
第5步：invokeBeanFactoryPostProcessors(beanFactory);
Invoke factory processors registered as beans in the context. 调用在context中注册为 bean 的工厂处理器。就是第4步注册的BeanFactoryPostProcess
执行过程有一个方法：doProcessConfigurationClass做如下事情 SpringBoot @ComponentScan在这步处理 SpringBoot @Import在这不处理 SpringBoot @ImportResource在这步处理 SpringBoot 处理@Bean在这步中 处理接口上的默认方法 如果有superclass，处理superclass。返回循环处理
public static void invokeBeanFactoryPostProcessors(
ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {
// 如果有的话，首先调用 BeanDefinitionRegistryPostProcessors
Set<String> processedBeans = new HashSet<>();
// AnnotationConfigServletWebServiceApplicationContext继承了ServletWebServiceApplicationContext
// ServletWebServiceApplicationContext 继承了 GenericWebApplicationContext
// GenericWebApplicationContext 继承了 GenericApplicationContext
// GenericApplicationContext 实现了 BeanDefinitionRegistry ， 所以 此beanFactory instanceof BeanDefinitionRegistry 为true
if (beanFactory instanceof BeanDefinitionRegistry) {
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();
List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();
for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
BeanDefinitionRegistryPostProcessor registryProcessor =
(BeanDefinitionRegistryPostProcessor) postProcessor;
// 注册 metadataReaderFactory、
registryProcessor.postProcessBeanDefinitionRegistry(registry);
registryProcessors.add(registryProcessor);
}
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.
// 不要在此处初始化 FactoryBeans：我们需要让所有常规 bean 保持未初始化状态，以便 bean 工厂后处理器应用到它们！
// 将实现 PriorityOrdered、Ordered 和其余部分的 BeanDefinitionRegistryPostProcessor 分开。
List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>();
// First, invoke the BeanDefinitionRegistryPostProcessors that implement PriorityOrdered.
// 首先，调用实现 PriorityOrdered(优先排序) 的 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);
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
// Next, invoke the BeanDefinitionRegistryPostProcessors that implement Ordered.
// 接下来，调用实现 Ordered 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);
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
// 调用 Bean 定义注册表后处理器，下面看详情
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
// Finally, invoke all other BeanDefinitionRegistryPostProcessors until no further ones appear.
// 最后，调用所有其他 BeanDefinitionRegistryPostProcessors 直到不再出现。
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.
// 现在，调用到目前为止处理的所有处理器的 postProcessBeanFactory 回调
invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
}
else {
// Invoke factory processors registered with the context instance.
// 调用向上下文实例注册的工厂处理器。
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!
// 不要在这里初始化 FactoryBeans：我们需要让所有常规 bean
// 未初始化，以便 bean 工厂后处理器应用到它们！
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
// Separate between BeanFactoryPostProcessors that implement PriorityOrdered,
// Ordered, and the rest.
// 将实现 PriorityOrdered、Ordered 的 BeanFactoryPostProcessor 和其余部分分开。
List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
List<String> orderedPostProcessorNames = new ArrayList<>();
List<String> nonOrderedPostProcessorNames = new ArrayList<>();
for (String ppName : postProcessorNames) {
if (processedBeans.contains(ppName)) {
// skip - already processed in first phase above
// 跳过 - 已在上述第一阶段处理
}
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 PriorityOrdered 的 BeanFactoryPostProcessor。
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);
// Next, invoke the BeanFactoryPostProcessors that implement Ordered.
// 接下来，调用实现 Ordered 的 BeanFactoryPostProcessors。
List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size());
for (String postProcessorName : orderedPostProcessorNames) {
orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
sortPostProcessors(orderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);
// Finally, invoke all other BeanFactoryPostProcessors.
// 最后，调用所有其他 BeanFactoryPostProcessor。
List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());
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...
// 清除缓存的合并 bean 定义，因为后处理器可能修改了原始元数据，例如替换值中的占位符...
beanFactory.clearMetadataCache();
}
调用 Bean 定义注册表后处理器，详情经过连续下钻到这个方法 下面代码String[] candidateNames = registry.getBeanDefinitionNames();得到的结果：
/**
* 基于 Configuration 类的注册表构建和验证配置模型
*/
public void processConfigBeanDefinitions(BeanDefinitionRegistry registry) {
List<BeanDefinitionHolder> configCandidates = new ArrayList<>();
String[] candidateNames = registry.getBeanDefinitionNames();
for (String beanName : candidateNames) {
BeanDefinition beanDef = registry.getBeanDefinition(beanName);
if (beanDef.getAttribute(ConfigurationClassUtils.CONFIGURATION_CLASS_ATTRIBUTE) != null) {
if (logger.isDebugEnabled()) {
logger.debug("Bean definition has already been processed as a configuration class: " + beanDef);
}
}
else if (ConfigurationClassUtils.checkConfigurationClassCandidate(beanDef, this.metadataReaderFactory)) {
configCandidates.add(new BeanDefinitionHolder(beanDef, beanName));
}
}
// Return immediately if no @Configuration classes were found
if (configCandidates.isEmpty()) {
return;
}
// Sort by previously determined @Order value, if applicable
configCandidates.sort((bd1, bd2) -> {
int i1 = ConfigurationClassUtils.getOrder(bd1.getBeanDefinition());
int i2 = ConfigurationClassUtils.getOrder(bd2.getBeanDefinition());
return Integer.compare(i1, i2);
});
// Detect any custom bean name generation strategy supplied through the enclosing application context
SingletonBeanRegistry sbr = null;
if (registry instanceof SingletonBeanRegistry) {
sbr = (SingletonBeanRegistry) registry;
if (!this.localBeanNameGeneratorSet) {
BeanNameGenerator generator = (BeanNameGenerator) sbr.getSingleton(
AnnotationConfigUtils.CONFIGURATION_BEAN_NAME_GENERATOR);
if (generator != null) {
this.componentScanBeanNameGenerator = generator;
this.importBeanNameGenerator = generator;
}
}
}
if (this.environment == null) {
this.environment = new StandardEnvironment();
}
// Parse each @Configuration class
ConfigurationClassParser parser = new ConfigurationClassParser(
this.metadataReaderFactory, this.problemReporter, this.environment,
this.resourceLoader, this.componentScanBeanNameGenerator, registry);
Set<BeanDefinitionHolder> candidates = new LinkedHashSet<>(configCandidates);
Set<ConfigurationClass> alreadyParsed = new HashSet<>(configCandidates.size());
do {
parser.parse(candidates);
parser.validate();
Set<ConfigurationClass> configClasses = new LinkedHashSet<>(parser.getConfigurationClasses());
configClasses.removeAll(alreadyParsed);
// Read the model and create bean definitions based on its content
if (this.reader == null) {
this.reader = new ConfigurationClassBeanDefinitionReader(
registry, this.sourceExtractor, this.resourceLoader, this.environment,
this.importBeanNameGenerator, parser.getImportRegistry());
}
// 加载所有的Bean定义信息
this.reader.loadBeanDefinitions(configClasses);
alreadyParsed.addAll(configClasses);
candidates.clear();
if (registry.getBeanDefinitionCount() > candidateNames.length) {
String[] newCandidateNames = registry.getBeanDefinitionNames();
Set<String> oldCandidateNames = new HashSet<>(Arrays.asList(candidateNames));
Set<String> alreadyParsedClasses = new HashSet<>();
for (ConfigurationClass configurationClass : alreadyParsed) {
alreadyParsedClasses.add(configurationClass.getMetadata().getClassName());
}
for (String candidateName : newCandidateNames) {
if (!oldCandidateNames.contains(candidateName)) {
BeanDefinition bd = registry.getBeanDefinition(candidateName);
if (ConfigurationClassUtils.checkConfigurationClassCandidate(bd, this.metadataReaderFactory) &&
!alreadyParsedClasses.contains(bd.getBeanClassName())) {
candidates.add(new BeanDefinitionHolder(bd, candidateName));
}
}
}
candidateNames = newCandidateNames;
}
}
while (!candidates.isEmpty());
// Register the ImportRegistry as a bean in order to support ImportAware @Configuration classes
if (sbr != null && !sbr.containsSingleton(IMPORT_REGISTRY_BEAN_NAME)) {
sbr.registerSingleton(IMPORT_REGISTRY_BEAN_NAME, parser.getImportRegistry());
}
if (this.metadataReaderFactory instanceof CachingMetadataReaderFactory) {
// Clear cache in externally provided MetadataReaderFactory; this is a no-op
// for a shared cache since it'll be cleared by the ApplicationContext.
((CachingMetadataReaderFactory) this.metadataReaderFactory).clearCache();
}
}
SpringBoot使用GenericBeanDefinition类作为BeanDefinition的实现类，看下类之间关系
注册BeanDefinition
public static final String BEAN_NAME = "org.springframework.boot.autoconfigure."
+ "internalCachingMetadataReaderFactory";
registry.registerBeanDefinition(BEAN_NAME, definition)
@Override
public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)
throws BeanDefinitionStoreException {
// org.springframework.boot.autoconfigure.internalCachingMetadataReaderFactory
Assert.hasText(beanName, "Bean name must not be empty");
Assert.notNull(beanDefinition, "BeanDefinition must not be null");
if (beanDefinition instanceof AbstractBeanDefinition) {
try {
// 验证
((AbstractBeanDefinition) beanDefinition).validate();
}
catch (BeanDefinitionValidationException ex) {
throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName,
"Validation of bean definition failed", ex);
}
}
// 获取 执行定义，在创建上下文是赋值 没取到 internalCachingMetadataReaderFactory
BeanDefinition existingDefinition = this.beanDefinitionMap.get(beanName);
if (existingDefinition != null) {
if (!isAllowBeanDefinitionOverriding()) {
throw new BeanDefinitionOverrideException(beanName, beanDefinition, existingDefinition);
}
else if (existingDefinition.getRole() < beanDefinition.getRole()) {
// e.g. was ROLE_APPLICATION, now overriding with ROLE_SUPPORT or ROLE_INFRASTRUCTURE
if (logger.isInfoEnabled()) {
logger.info("Overriding user-defined bean definition for bean '" + beanName +
"' with a framework-generated bean definition: replacing [" +
existingDefinition + "] with [" + beanDefinition + "]");
}
}
else if (!beanDefinition.equals(existingDefinition)) {
if (logger.isDebugEnabled()) {
logger.debug("Overriding bean definition for bean '" + beanName +
"' with a different definition: replacing [" + existingDefinition +
"] with [" + beanDefinition + "]");
}
}
else {
if (logger.isTraceEnabled()) {
logger.trace("Overriding bean definition for bean '" + beanName +
"' with an equivalent definition: replacing [" + existingDefinition +
"] with [" + beanDefinition + "]");
}
}
this.beanDefinitionMap.put(beanName, beanDefinition);
}
else {
// 已创建的Bean不是空的
if (hasBeanCreationStarted()) {
// Cannot modify startup-time collection elements anymore (for stable iteration)
// 无法再修改启动时集合元素（用于稳定迭代）
synchronized (this.beanDefinitionMap) {
this.beanDefinitionMap.put(beanName, beanDefinition);
List<String> updatedDefinitions = new ArrayList<>(this.beanDefinitionNames.size() + 1);
updatedDefinitions.addAll(this.beanDefinitionNames);
updatedDefinitions.add(beanName);
this.beanDefinitionNames = updatedDefinitions;
//删除手动单例名称
removeManualSingletonName(beanName);
}
}
else {
// Still in startup registration phase
// 仍处于启动注册阶段
// 把 internalCachingMetadataReaderFactory 放进bean定义Map
this.beanDefinitionMap.put(beanName, beanDefinition);
// 添加名称
this.beanDefinitionNames.add(beanName);
removeManualSingletonName(beanName);
}
this.frozenBeanDefinitionNames = null;
}
if (existingDefinition != null || containsSingleton(beanName)) {
resetBeanDefinition(beanName);
}
else if (isConfigurationFrozen()) {
clearByTypeCache();
}
}
第6步：registerBeanPostProcessors(beanFactory);
Register bean processors that intercept bean creation. 注册 BeanProcessors。
这里取到9个BeanPorcessors
// 实例化并注册所有 BeanPostProcessor bean，如果给定，则尊重显式顺序。必须在应用程序 bean 的任何实例化之前调用
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.
// 当bean 不符合被所有 BeanPostProcessor 处理的条件，在 BeanPostProcessor 实例化期间创建 bean 时记录信息消息
// 即当bean 不符合被所有 BeanPostProcessor 处理的条件，注册 BeanPostProcessorChecker，，
int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));
// Separate between BeanPostProcessors that implement PriorityOrdered,
// Ordered, and the rest.
// 将实现 PriorityOrdered、Ordered 和其余部分的 BeanPostProcessor 分开
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 PriorityOrdered 的 BeanPostProcessor。
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);
// Next, register the BeanPostProcessors that implement Ordered.
// 接下来，注册实现 Ordered 的 BeanPostProcessor。
List<BeanPostProcessor> orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size());
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.
// 现在，注册所有常规的 BeanPostProcessor。
List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());
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，重新注册所有内部 BeanPostProcessor。
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).
// 重新注册用于将内部 bean 检测为 ApplicationListeners 的后处理器，
// 将其移动到处理器链的末尾（用于拾取代理等）
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}
第7步：initMessageSource();
Initialize message source for this context. 初始化此上下文的消息源 把消息源注册到beanFactory中
protected void initMessageSource() {
ConfigurableListableBeanFactory beanFactory = getBeanFactory();
if (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) {
this.messageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class);
// Make MessageSource aware of parent MessageSource.
// 使 MessageSource 了解父 MessageSource。
if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource) {
HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource;
if (hms.getParentMessageSource() == null) {
// Only set parent context as parent MessageSource if no parent MessageSource
// registered already.
// 如果没有父消息源 已经注册，则仅将父上下文设置为父消息源。
hms.setParentMessageSource(getInternalParentMessageSource());
}
}
if (logger.isTraceEnabled()) {
logger.trace("Using MessageSource [" + this.messageSource + "]");
}
}
else {
// Use empty MessageSource to be able to accept getMessage calls.
// 使用空 MessageSource 能够接受 getMessage 调用
DelegatingMessageSource dms = new DelegatingMessageSource();
dms.setParentMessageSource(getInternalParentMessageSource());
this.messageSource = dms;
beanFactory.registerSingleton(MESSAGE_SOURCE_BEAN_NAME, this.messageSource);
if (logger.isTraceEnabled()) {
logger.trace("No '" + MESSAGE_SOURCE_BEAN_NAME + "' bean, using [" + this.messageSource + "]");
}
}
}
第8步：initApplicationEventMulticaster();
Initialize event multicaster for this context. 初始化此context的事件多播器
// 工厂中 ApplicationEventMulticaster bean 的名称。 如果没有提供，则使用默认的
public static final String APPLICATION_EVENT_MULTICASTER_BEAN_NAME = "applicationEventMulticaster";
/**
* 初始化 ApplicationEventMulticaster。
* 如果上下文中没有定义，则使用 SimpleApplicationEventMulticaster。
* @see org.springframework.context.event.SimpleApplicationEventMulticaster
*/
protected void initApplicationEventMulticaster() {
ConfigurableListableBeanFactory beanFactory = getBeanFactory();
if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
this.applicationEventMulticaster =
beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
if (logger.isTraceEnabled()) {
logger.trace("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
}
}
else {
this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
// 把简单多播器注册到beanFactory中
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() + "]");
}
}
}
SimpleApplicationEventMulticaster
第9步：onRefresh();
Initialize other special beans in specific context subclasses. 翻译：初始化特定上下文子类中的其他特殊 bean。
protected void onRefresh() {
super.onRefresh();
try {
// 创建Web服务
createWebServer();
}
catch (Throwable ex) {
throw new ApplicationContextException("Unable to start web server", ex);
}
}
第10步：registerListeners();
Check for listener beans and register them. 翻译：注册检查侦听器 bean 们
protected void registerListeners() {
// Register statically specified listeners first.
// 首先注册静态指定的监听器。
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!
// 不要在这里初始化 FactoryBeans：我们需要让所有常规 bean
// 未初始化，以便让后处理器应用于它们！
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...
// 发布早期应用程序事件，因为我们终于有了一个多播器......
Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;
this.earlyApplicationEvents = null;
if (!CollectionUtils.isEmpty(earlyEventsToProcess)) {
for (ApplicationEvent earlyEvent : earlyEventsToProcess) {
getApplicationEventMulticaster().multicastEvent(earlyEvent);
}
}
}
第11步：finishBeanFactoryInitialization(beanFactory);
Instantiate all remaining (non-lazy-init) singletons. 翻译：实例化所有剩余的（非惰性初始化）单例。
protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {
// Initialize conversion service for this context.
// 为此上下文初始化转换服务。beanFactory是否包含conversionService 且 conversionService是否是ConversionService.class类型
// 我这里启动是条件为false
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.
// 如果之前没有注册过任何 bean 后处理器
//（例如 PropertyPlaceholderConfigurer bean），则注册一个默认的嵌入值解析器： 此时，主要用于解析注释属性值。
// 我这里启动是条件为false
if (!beanFactory.hasEmbeddedValueResolver()) {
beanFactory.addEmbeddedValueResolver(strVal -> getEnvironment().resolvePlaceholders(strVal));
}
// Initialize LoadTimeWeaverAware beans early to allow for registering their transformers early.
// 尽早初始化 LoadTimeWeaverAware bean，以便尽早注册它们的转换器。
String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false);
for (String weaverAwareName : weaverAwareNames) {
getBean(weaverAwareName);
}
// Stop using the temporary ClassLoader for type matching.
// 停止使用临时 ClassLoader 进行类型匹配。
beanFactory.setTempClassLoader(null);
// Allow for caching all bean definition metadata, not expecting further changes.
// 允许缓存所有 bean 定义元数据，而不是期望进一步的更改。
beanFactory.freezeConfiguration();
// Instantiate all remaining (non-lazy-init) singletons.
// 实例化所有剩余的（非惰性初始化）单例。 看下面详解
beanFactory.preInstantiateSingletons();
}
beanFactory.preInstantiateSingletons();详解，使用的DefaultListableBeanFactory的方法
@Override
public void preInstantiateSingletons() throws BeansException {
if (logger.isTraceEnabled()) {
logger.trace("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.
// 迭代一个副本以允许 init 方法依次注册新的 bean 定义。
// 虽然这可能不是常规工厂引导程序的一部分，但它确实可以正常工作。
List<String> beanNames = new ArrayList<>(this.beanDefinitionNames);
// Trigger initialization of all non-lazy singleton beans...
for (String beanName : beanNames) {
RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);
// 判断条件：不是抽象的 且 是单例的 且 不是懒加载
if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) {
// 是工厂Bean
if (isFactoryBean(beanName)) {
// 拼接&前缀
Object bean = getBean(FACTORY_BEAN_PREFIX + beanName);
if (bean instanceof FactoryBean) {
FactoryBean<?> factory = (FactoryBean<?>) bean;
boolean isEagerInit;
// 系统安全接口不是空 且 工厂bean是SmartFactoryBean类型
if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {
isEagerInit = AccessController.doPrivileged(
(PrivilegedAction<Boolean>) ((SmartFactoryBean<?>) factory)::isEagerInit,
getAccessControlContext());
}
else {
// 是SmartFactoryBean 且 是急切初始化的 则为true
isEagerInit = (factory instanceof SmartFactoryBean &&
((SmartFactoryBean<?>) factory).isEagerInit());
}
if (isEagerInit) {
// Spring DI 的一个入口
getBean(beanName);
}
}
}
else {
// Spring DI 的一个入口
getBean(beanName);
}
}
}
// Trigger post-initialization callback for all applicable beans...
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();
}
}
}
}
第12步：finishRefresh();
Last step: publish corresponding event. 最后一步：发布相应的事件
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（例如扫描中的 ASM 元数据）。
// this.resourceCaches.clear();
clearResourceCaches();
// Initialize lifecycle processor for this context.
// 为此上下文初始化生命周期处理器。
initLifecycleProcessor();
// Propagate refresh to lifecycle processor first.
// 首先将刷新传播到生命周期处理器。
getLifecycleProcessor().onRefresh();
// Publish the final event.
// 发布最终事件。
publishEvent(new ContextRefreshedEvent(this));
// Participate in LiveBeansView MBean, if active.
// 参与 LiveBeansView MBean（如果处于活动状态）。
LiveBeansView.registerApplicationContext(this);
}
第13步：resetCommonCaches();
重置 Spring 核心中的常见自省缓存，因为我们可能不再需要单例 bean 的元数据......
protected void resetCommonCaches() {
ReflectionUtils.clearCache();
AnnotationUtils.clearCache();
ResolvableType.clearCache();
CachedIntrospectionResults.clearClassLoader(getClassLoader());
}
至此，刷新上下文全部模板方法已经执行完毕~