spring 关键方法

org.springframework.context.support.AbstractApplicationContext#refresh

这个方法 是 线程安全的

synchronized (this.startupShutdownMonitor) { }

第一步，资源相关，初始化 属性资源 并验证

org.springframework.context.support.AbstractApplicationContext#prepareRefresh

initPropertySources(); 该方法提供给子类实现，实现该方法的子类有：

// org.springframework.web.context.support.AbstractRefreshableWebApplicationContext#initPropertySources
protected void initPropertySources() {ConfigurableEnvironment env = getEnvironment();if (env instanceof ConfigurableWebEnvironment) {((ConfigurableWebEnvironment) env).initPropertySources(this.servletContext, this.servletConfig);}}public static void initServletPropertySources(MutablePropertySources sources,@Nullable ServletContext servletContext, @Nullable ServletConfig servletConfig) {Assert.notNull(sources, "'propertySources' must not be null");String name = StandardServletEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME;if (servletContext != null && sources.get(name) instanceof StubPropertySource) {sources.replace(name, new ServletContextPropertySource(name, servletContext));}name = StandardServletEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME;if (servletConfig != null && sources.get(name) instanceof StubPropertySource) {sources.replace(name, new ServletConfigPropertySource(name, servletConfig));}}

// org.springframework.web.context.support.GenericWebApplicationContext#initPropertySources
protected void initPropertySources() {ConfigurableEnvironment env = getEnvironment();if (env instanceof ConfigurableWebEnvironment) {((ConfigurableWebEnvironment) env).initPropertySources(this.servletContext, null);}}public static void initServletPropertySources(MutablePropertySources sources,@Nullable ServletContext servletContext, @Nullable ServletConfig servletConfig) {Assert.notNull(sources, "'propertySources' must not be null");String name = StandardServletEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME;if (servletContext != null && sources.get(name) instanceof StubPropertySource) {sources.replace(name, new ServletContextPropertySource(name, servletContext));}name = StandardServletEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME;if (servletConfig != null && sources.get(name) instanceof StubPropertySource) {sources.replace(name, new ServletConfigPropertySource(name, servletConfig));}}

// org.springframework.web.context.support.StaticWebApplicationContext#initPropertySources
protected void initPropertySources() {WebApplicationContextUtils.initServletPropertySources(getEnvironment().getPropertySources(),this.servletContext, this.servletConfig);}public static void initServletPropertySources(MutablePropertySources sources,@Nullable ServletContext servletContext, @Nullable ServletConfig servletConfig) {Assert.notNull(sources, "'propertySources' must not be null");String name = StandardServletEnvironment.SERVLET_CONTEXT_PROPERTY_SOURCE_NAME;if (servletContext != null && sources.get(name) instanceof StubPropertySource) {sources.replace(name, new ServletContextPropertySource(name, servletContext));}name = StandardServletEnvironment.SERVLET_CONFIG_PROPERTY_SOURCE_NAME;if (servletConfig != null && sources.get(name) instanceof StubPropertySource) {sources.replace(name, new ServletConfigPropertySource(name, servletConfig));}}

getEnvironment().validateRequiredProperties(); 验证属性值

// 获取 applicationListeners

// 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);}

第二步：

// Tell the subclass to refresh the internal bean factory.
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

org.springframework.context.support.AbstractApplicationContext#refreshBeanFactory 是一个抽象方法，有两个实现：

第一个实现：

org.springframework.context.support.AbstractRefreshableApplicationContext#refreshBeanFactory

首先 DefaultListableBeanFactory beanFactory = new DefaultListableBeanFactory(getInternalParentBeanFactory());

配置 是否可以 覆盖bean 和 循环依赖

protected void customizeBeanFactory(DefaultListableBeanFactory beanFactory) {if (this.allowBeanDefinitionOverriding != null) {beanFactory.setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);}if (this.allowCircularReferences != null) {beanFactory.setAllowCircularReferences(this.allowCircularReferences);}}

org.springframework.context.support.AbstractRefreshableApplicationContext#loadBeanDefinitions 调用 该方法加载bean信息，该方法由子类实现：

org.springframework.context.support.AbstractXmlApplicationContext#loadBeanDefinitions(org.springframework.beans.factory.support.DefaultListableBeanFactory)

org.springframework.web.context.support.AnnotationConfigWebApplicationContext#loadBeanDefinitions

org.springframework.web.context.support.GroovyWebApplicationContext#loadBeanDefinitions(org.springframework.beans.factory.support.DefaultListableBeanFactory)

org.springframework.web.context.support.XmlWebApplicationContext#loadBeanDefinitions(org.springframework.beans.factory.support.DefaultListableBeanFactory)

第二个实现：

org.springframework.context.support.GenericApplicationContext#refreshBeanFactory

protected final void refreshBeanFactory() throws IllegalStateException {if (!this.refreshed.compareAndSet(false, true)) {throw new IllegalStateException("GenericApplicationContext does not support multiple refresh attempts: just call 'refresh' once");}this.beanFactory.setSerializationId(getId());}

因为 spring boot 启动 servlet模式使用的是 org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext 继承自 org.springframework.web.context.support.GenericWebApplicationContext，因此 这里实际基本等于啥都没做。而 beanfactory 在实例化 时构造。

public GenericApplicationContext() {this.beanFactory = new DefaultListableBeanFactory();}

第三步：

prepareBeanFactory(beanFactory);

设置 类加载器

beanFactory.setBeanClassLoader(getClassLoader());

设置Bean表达式解析器，以便解析Bean定义中的SpEL表达式

beanFactory.setBeanExpressionResolver(newStandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));

 注册资源编辑器注册器，用于自定义属性编辑器支持

beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));

// 添加ApplicationContextAwareProcessor，使得Bean能感知到ApplicationContext，加入private final List<BeanPostProcessor> beanPostProcessors = new CopyOnWriteArrayList<>();

beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));

// 配置BeanFactory忽略特定接口的依赖注入，这些接口的实现通常由框架直接提供服务,加入private final Set<Class<?>> ignoredDependencyInterfaces = new HashSet<>();

beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);

// 注册可解析依赖：BeanFactory、ResourceLoader、ApplicationEventPublisher和ApplicationContext本身

beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
beanFactory.registerResolvableDependency(ResourceLoader.class, this);
beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
beanFactory.registerResolvableDependency(ApplicationContext.class, this);

    // 添加早期后处理器，用于检测内部Bean作为ApplicationListener

beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));

    // 如果存在LoadTimeWeaver，准备进行类加载期织入的配置

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()));
}

    // 注册默认的环境相关Bean，如Environment、系统属性和系统环境变量

f (!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());
}

第四步：

postProcessBeanFactory(beanFactory);

这个方法的实现比较多，有8个

// 	org.springframework.web.context.support.AbstractRefreshableWebApplicationContext#postProcessBeanFactory
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {beanFactory.addBeanPostProcessor(new ServletContextAwareProcessor(this.servletContext, this.servletConfig));beanFactory.ignoreDependencyInterface(ServletContextAware.class);beanFactory.ignoreDependencyInterface(ServletConfigAware.class);WebApplicationContextUtils.registerWebApplicationScopes(beanFactory, this.servletContext);WebApplicationContextUtils.registerEnvironmentBeans(beanFactory, this.servletContext, this.servletConfig);}

// org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext#postProcessBeanFactory
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {super.postProcessBeanFactory(beanFactory);if (!ObjectUtils.isEmpty(this.basePackages)) {this.scanner.scan(this.basePackages);}if (!this.annotatedClasses.isEmpty()) {this.reader.register(ClassUtils.toClassArray(this.annotatedClasses));}}

// org.springframework.boot.web.servlet.context.AnnotationConfigServletWebApplicationContext#postProcessBeanFactory
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {super.postProcessBeanFactory(beanFactory);if (!ObjectUtils.isEmpty(this.basePackages)) {this.scanner.scan(this.basePackages);}if (!this.annotatedClasses.isEmpty()) {this.reader.register(ClassUtils.toClassArray(this.annotatedClasses));}}

// org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext#postProcessBeanFactory
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {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));}}

// org.springframework.web.context.support.GenericWebApplicationContext#postProcessBeanFactory
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {if (this.servletContext != null) {beanFactory.addBeanPostProcessor(new ServletContextAwareProcessor(this.servletContext));beanFactory.ignoreDependencyInterface(ServletContextAware.class);}WebApplicationContextUtils.registerWebApplicationScopes(beanFactory, this.servletContext);WebApplicationContextUtils.registerEnvironmentBeans(beanFactory, this.servletContext);}

// org.springframework.jca.context.ResourceAdapterApplicationContext#postProcessBeanFactory
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {beanFactory.addBeanPostProcessor(new BootstrapContextAwareProcessor(this.bootstrapContext));beanFactory.ignoreDependencyInterface(BootstrapContextAware.class);beanFactory.registerResolvableDependency(BootstrapContext.class, this.bootstrapContext);BootstrapContext var10002 = this.bootstrapContext;beanFactory.registerResolvableDependency(WorkManager.class, var10002::getWorkManager);}
}

//org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext#postProcessBeanFactory
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {beanFactory.addBeanPostProcessor(new WebApplicationContextServletContextAwareProcessor(this));beanFactory.ignoreDependencyInterface(ServletContextAware.class);registerWebApplicationScopes();}

//org.springframework.web.context.support.StaticWebApplicationContext#postProcessBeanFactory
protected void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) {beanFactory.addBeanPostProcessor(new ServletContextAwareProcessor(this.servletContext, this.servletConfig));beanFactory.ignoreDependencyInterface(ServletContextAware.class);beanFactory.ignoreDependencyInterface(ServletConfigAware.class);WebApplicationContextUtils.registerWebApplicationScopes(beanFactory, this.servletContext);WebApplicationContextUtils.registerEnvironmentBeans(beanFactory, this.servletContext, this.servletConfig);}

第五步：

invokeBeanFactoryPostProcessors(beanFactory);

protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());// Detect a LoadTimeWeaver and prepare for weaving, if found in the meantime// (e.g. through an @Bean method registered by ConfigurationClassPostProcessor)if (beanFactory.getTempClassLoader() == null && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));}}

.获取所有的BeanFactoryPostProcessor

public List<BeanFactoryPostProcessor> getBeanFactoryPostProcessors() {return this.beanFactoryPostProcessors;}

. PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());

这里也比较复杂，该函数用于在Spring应用程序上下文中调用BeanFactoryPostProcessor和BeanDefinitionRegistryPostProcessor的实例。这些处理器可以在Spring容器实例化任何bean之前修改bean的定义或bean工厂的配置。

第一部分：调用 BeanDefinitionRegistryPostProcessor

行 org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor#postProcessBeanDefinitionRegistry

从bean工厂中读取所有的 BeanDefinitionRegistryPostProcessor

优先排序 并调用 实现了 org.springframework.core.PriorityOrdered 接口的。

然后排序 并调用 实现了 org.springframework.core.Ordered 接口的

最后调用剩下的

调用 所有的 org.springframework.beans.factory.config.BeanFactoryPostProcessor#postProcessBeanFactory

第二部分：调用 BeanFactoryPostProcessor

也是按照PriorityOrdered/Ordered 顺序调用

第六步：registerBeanPostProcessors(beanFactory);

这一步看着停复杂，实际就做一件事，读取所有的 BeanPostProcessor，按照优先级排序后

写入 org.springframework.beans.factory.support.AbstractBeanFactory#beanPostProcessors

第七/八步：

initMessageSource();

initApplicationEventMulticaster();

第九步：

onRefresh();

实现类也挺多

org.springframework.web.context.support.AbstractRefreshableWebApplicationContext#onRefreshprotected void onRefresh() {
this.themeSource = UiApplicationContextUtils.initThemeSource(this);
}org.springframework.web.context.support.GenericWebApplicationContext#onRefreshprotected void onRefresh() {
this.themeSource = UiApplicationContextUtils.initThemeSource(this);
}org.springframework.boot.web.reactive.context.ReactiveWebServerApplicationContext#onRefreshprotected void onRefresh() {
super.onRefresh();
try {
createWebServer();
}
catch (Throwable ex) {
throw new ApplicationContextException("Unable to start reactive web server", ex);
}
}org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext#onRefreshprotected void onRefresh() {
super.onRefresh();
try {
createWebServer();
}
catch (Throwable ex) {
throw new ApplicationContextException("Unable to start web server", ex);
}
}org.springframework.web.context.support.StaticWebApplicationContext#onRefreshprotected void onRefresh() {
this.themeSource = UiApplicationContextUtils.initThemeSource(this);
}

第十步：

registerListeners();

注册 ApplicationListener

第十一步：

finishBeanFactoryInitialization(beanFactory);

完成bean的实例化

第十二步：

/**
 * 完成此上下文的刷新操作，包括调用生命周期处理器的onRefresh()方法，
 * 发布ContextRefreshedEvent事件，以及参与LiveBeansView MBean（如激活）。
 */
protected void finishRefresh() {
    // 清除上下文级别的资源缓存（例如扫描期间获取的ASM元数据）。
    clearResourceCaches();

    // 初始化此上下文的生命周期处理器。
    initLifecycleProcessor();

    // 首先将刷新操作传播给生命周期处理器。
    getLifecycleProcessor().onRefresh();

    // 发布最终的刷新事件。
    publishEvent(new ContextRefreshedEvent(this));

    // 如LiveBeansView MBean处于活动状态，注册此应用上下文以参与其中。
    LiveBeansView.registerApplicationContext(this);
}

 

finally:

protected void resetCommonCaches() {
ReflectionUtils.clearCache();
AnnotationUtils.clearCache();
ResolvableType.clearCache();
CachedIntrospectionResults.clearClassLoader(getClassLoader());
}