Spring 容器刷新流程（refresh）源码全解

🔄 Spring 容器刷新流程（refresh）源码全解

🎯 一、Spring 容器启动的整体流程概览

🔄 Spring 容器启动全景图

​​ApplicationContext 启动流程总览​​：

⏱️ 启动阶段时间线

​​容器启动关键节点时序​​：

timelinetitle Spring 容器启动时间线section 准备阶段环境准备 : 初始化属性源BeanFactory创建 : 加载Bean定义BeanFactory配置 : 配置类加载器section 后处理阶段BeanFactory后处理 : 执行BeanFactoryPostProcessorBean后处理注册 : 注册BeanPostProcessor消息源初始化 : 国际化支持section 事件阶段事件广播器 : 初始化事件多播器特殊Bean初始化 : 子类扩展点监听器注册 : 注册事件监听器section 完成阶段单例预实例化 : 初始化非懒加载单例上下文刷新完成 : 发布刷新事件生命周期启动 : 启动Lifecycle Bean

🔄 二、refresh 方法的执行阶段全解析

🚀 refresh() 方法核心框架

​​AbstractApplicationContext#refresh() 完整源码结构​​：

@Override
public void refresh() throws BeansException, IllegalStateException {synchronized (this.startupShutdownMonitor) {// 阶段1: 准备刷新上下文prepareRefresh();// 阶段2: 获取BeanFactory并加载Bean定义ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();// 阶段3: 准备BeanFactory（配置类加载器、添加BeanPostProcessor等）prepareBeanFactory(beanFactory);try {// 阶段4: 后处理BeanFactory（子类扩展点）postProcessBeanFactory(beanFactory);// 阶段5: 调用BeanFactory后处理器invokeBeanFactoryPostProcessors(beanFactory);// 阶段6: 注册Bean后处理器registerBeanPostProcessors(beanFactory);// 阶段7: 初始化消息源（国际化）initMessageSource();// 阶段8: 初始化事件广播器initApplicationEventMulticaster();// 阶段9: 初始化特殊Bean（子类扩展）onRefresh();// 阶段10: 注册事件监听器registerListeners();// 阶段11: 实例化所有非懒加载单例BeanfinishBeanFactoryInitialization(beanFactory);// 阶段12: 完成刷新，发布上下文刷新事件finishRefresh();} catch (BeansException ex) {// 阶段13: 销毁已创建的单例BeandestroyBeans();// 阶段14: 重置激活标志cancelRefresh(ex);throw ex;}}
}

🔧 阶段1：prepareRefresh() - 准备刷新

​​容器启动前的准备工作​​：

protected void prepareRefresh() {// 1. 记录启动时间戳this.startupDate = System.currentTimeMillis();this.closed.set(false);this.active.set(true);// 2. 初始化上下文环境中的占位符属性源initPropertySources();// 3. 验证必需属性getEnvironment().validateRequiredProperties();// 4. 存储早期应用事件this.earlyApplicationEvents = new LinkedHashSet<>();// 5. 日志记录启动信息if (logger.isDebugEnabled()) {logger.debug("Refreshing " + this);}
}

​​初始化属性源示例​​：

@Override
protected void initPropertySources() {// 为子类提供自定义属性源的机会ConfigurableEnvironment env = getEnvironment();if (env instanceof ConfigurableWebEnvironment) {((ConfigurableWebEnvironment) env).initPropertySources(this.servletContext, null);}
}

🏗️ 阶段2：obtainFreshBeanFactory() - 获取BeanFactory

​​BeanFactory 创建与加载流程​​：

protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {// 1. 刷新BeanFactory（抽象方法，由子类实现）refreshBeanFactory();// 2. 获取刷新后的BeanFactoryConfigurableListableBeanFactory beanFactory = getBeanFactory();if (logger.isDebugEnabled()) {logger.debug("Bean factory for " + getDisplayName() + ": " + beanFactory);}return beanFactory;
}

​​子类实现示例（GenericApplicationContext）​​：

@Override
protected final void refreshBeanFactory() throws IllegalStateException {// 1. 如果已有BeanFactory，先销毁if (hasBeanFactory()) {destroyBeans();closeBeanFactory();}try {// 2. 创建新的BeanFactoryDefaultListableBeanFactory beanFactory = createBeanFactory();beanFactory.setSerializationId(getId());// 3. 定制BeanFactory（允许覆盖）customizeBeanFactory(beanFactory);// 4. 加载Bean定义loadBeanDefinitions(beanFactory);// 5. 设置BeanFactory引用this.beanFactory = beanFactory;} catch (IOException ex) {throw new ApplicationContextException("I/O error parsing bean definition source", ex);}
}

⚙️ 阶段3：prepareBeanFactory() - 配置BeanFactory

​​BeanFactory 基础配置​​：

protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {// 1. 设置类加载器beanFactory.setBeanClassLoader(getClassLoader());beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory));beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));// 2. 添加BeanPostProcessor（ApplicationContextAwareProcessor）beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));// 3. 忽略依赖接口（这些接口由ApplicationContext自动注入）beanFactory.ignoreDependencyInterface(EnvironmentAware.class);beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);beanFactory.ignoreDependencyInterface(MessageSourceAware.class);beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);// 4. 注册可解析的依赖beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);beanFactory.registerResolvableDependency(ResourceLoader.class, this);beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);beanFactory.registerResolvableDependency(ApplicationContext.class, this);// 5. 添加ApplicationListener探测器beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));// 6. 如果存在LoadTimeWeaver，则添加对应的BeanPostProcessorif (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));}// 7. 注册环境Beanif (!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());}
}

⚙️ 三、BeanFactoryPostProcessor 与 BeanPostProcessor 初始化

🔄 BeanFactoryPostProcessor 调用流程

​​BeanFactory后处理器执行机制​​：

protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {// 1. 获取所有BeanFactoryPostProcessor并排序PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors());// 2. 清除元数据缓存（如果已设置临时类加载器）if (beanFactory.getTempClassLoader() == null) {beanFactory.clearMetadataCache();}
}

​​PostProcessorRegistrationDelegate 核心逻辑​​：

public static void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {// 1. 调用BeanDefinitionRegistryPostProcessor（优先级最高）Set<String> processedBeans = new HashSet<>();if (beanFactory instanceof BeanDefinitionRegistry) {BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();// 1.1 首先处理实现了PriorityOrdered的BeanDefinitionRegistryPostProcessorString[] postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);for (String ppName : postProcessorNames) {if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {BeanDefinitionRegistryPostProcessor pp = beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class);registryProcessors.add(pp);processedBeans.add(ppName);}}sortPostProcessors(registryProcessors, beanFactory);invokeBeanDefinitionRegistryPostProcessors(registryProcessors, registry);// 1.2 处理实现了Ordered的BeanDefinitionRegistryPostProcessorregistryProcessors.clear();for (String ppName : postProcessorNames) {if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {BeanDefinitionRegistryPostProcessor pp = beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class);registryProcessors.add(pp);processedBeans.add(ppName);}}sortPostProcessors(registryProcessors, beanFactory);invokeBeanDefinitionRegistryPostProcessors(registryProcessors, registry);// 1.3 处理常规的BeanDefinitionRegistryPostProcessorregistryProcessors.clear();for (String ppName : postProcessorNames) {if (!processedBeans.contains(ppName)) {BeanDefinitionRegistryPostProcessor pp = beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class);registryProcessors.add(pp);processedBeans.add(ppName);}}sortPostProcessors(registryProcessors, beanFactory);invokeBeanDefinitionRegistryPostProcessors(registryProcessors, registry);// 2. 调用BeanFactoryPostProcessor（按优先级顺序）invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);// 2.1 处理实现了PriorityOrdered的BeanFactoryPostProcessorString[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();for (String ppName : postProcessorNames) {if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {BeanFactoryPostProcessor pp = beanFactory.getBean(ppName, BeanFactoryPostProcessor.class);priorityOrderedPostProcessors.add(pp);processedBeans.add(ppName);}}sortPostProcessors(priorityOrderedPostProcessors, beanFactory);invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);// 2.2 处理实现了Ordered的BeanFactoryPostProcessorList<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>();for (String ppName : postProcessorNames) {if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {BeanFactoryPostProcessor pp = beanFactory.getBean(ppName, BeanFactoryPostProcessor.class);orderedPostProcessors.add(pp);processedBeans.add(ppName);}}sortPostProcessors(orderedPostProcessors, beanFactory);invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);// 2.3 处理常规的BeanFactoryPostProcessorList<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>();for (String ppName : postProcessorNames) {if (!processedBeans.contains(ppName)) {BeanFactoryPostProcessor pp = beanFactory.getBean(ppName, BeanFactoryPostProcessor.class);nonOrderedPostProcessors.add(pp);processedBeans.add(ppName);}}invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);} else {// 非BeanDefinitionRegistry的直接调用invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);}
}

🛠️ BeanPostProcessor 注册流程

​​Bean后处理器注册机制​​：

protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) {PostProcessorRegistrationDelegate.registerBeanPostProcessors(beanFactory, this);
}

​​BeanPostProcessor 注册详细流程​​：

public static void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {// 1. 获取所有BeanPostProcessor的Bean名称String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);// 2. 注册BeanPostProcessorChecker（用于日志记录）int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));// 3. 按优先级分类注册BeanPostProcessorList<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();List<BeanPostProcessor> internalPostProcessors = new ArrayList<>();List<String> orderedPostProcessorNames = new ArrayList<>();List<String> nonOrderedPostProcessorNames = new ArrayList<>();// 3.1 分类处理for (String ppName : postProcessorNames) {if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);priorityOrderedPostProcessors.add(pp);if (pp instanceof MergedBeanDefinitionPostProcessor) {internalPostProcessors.add(pp);}} else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {orderedPostProcessorNames.add(ppName);} else {nonOrderedPostProcessorNames.add(ppName);}}// 3.2 注册实现了PriorityOrdered的BeanPostProcessorsortPostProcessors(priorityOrderedPostProcessors, beanFactory);registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);// 3.3 注册实现了Ordered的BeanPostProcessorList<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);// 3.4 注册常规BeanPostProcessorList<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);// 3.5 重新注册内部BeanPostProcessor（确保在最后执行）sortPostProcessors(internalPostProcessors, beanFactory);registerBeanPostProcessors(beanFactory, internalPostProcessors);// 3.6 添加ApplicationListener探测器beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}

📢 四、事件、多播、监听器注册阶段

🔊 事件系统初始化流程

​​消息源初始化​​：

protected void initMessageSource() {ConfigurableListableBeanFactory beanFactory = getBeanFactory();// 1. 检查是否已存在MessageSource Beanif (beanFactory.containsLocalBean(MESSAGE_SOURCE_BEAN_NAME)) {this.messageSource = beanFactory.getBean(MESSAGE_SOURCE_BEAN_NAME, MessageSource.class);// 设置父MessageSource以支持嵌套解析if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource) {HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource;if (hms.getParentMessageSource() == null) {hms.setParentMessageSource(getInternalParentMessageSource());}}if (logger.isDebugEnabled()) {logger.debug("Using MessageSource [" + this.messageSource + "]");}} else {// 2. 创建默认的DelegatingMessageSourceDelegatingMessageSource dms = new DelegatingMessageSource();dms.setParentMessageSource(getInternalParentMessageSource());this.messageSource = dms;beanFactory.registerSingleton(MESSAGE_SOURCE_BEAN_NAME, this.messageSource);if (logger.isDebugEnabled()) {logger.debug("Unable to locate MessageSource with name '" + MESSAGE_SOURCE_BEAN_NAME + "': using default [" + this.messageSource + "]");}}
}

​​事件广播器初始化​​：

protected void initApplicationEventMulticaster() {ConfigurableListableBeanFactory beanFactory = getBeanFactory();// 1. 检查是否已存在ApplicationEventMulticaster Beanif (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {this.applicationEventMulticaster = beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);if (logger.isDebugEnabled()) {logger.debug("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");}} else {// 2. 创建默认的SimpleApplicationEventMulticasterthis.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);if (logger.isDebugEnabled()) {logger.debug("Unable to locate ApplicationEventMulticaster with name '" + APPLICATION_EVENT_MULTICASTER_BEAN_NAME + "': using default [" + this.applicationEventMulticaster + "]");}}
}

👂 监听器注册机制

​​事件监听器注册流程​​：

protected void registerListeners() {// 1. 注册静态指定的监听器for (ApplicationListener<?> listener : getApplicationListeners()) {getApplicationEventMulticaster().addApplicationListener(listener);}// 2. 从BeanFactory中检测并注册监听器BeanString[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);for (String listenerBeanName : listenerBeanNames) {getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);}// 3. 发布早期事件（如果有）Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;this.earlyApplicationEvents = null;if (earlyEventsToProcess != null) {for (ApplicationEvent earlyEvent : earlyEventsToProcess) {getApplicationEventMulticaster().multicastEvent(earlyEvent);}}
}

🎯 子类扩展点：onRefresh()

​​模板方法供子类扩展​​：

protected void onRefresh() throws BeansException {// 空实现，子类可以重写此方法以添加特定的初始化逻辑// 例如：初始化特定于Web的Bean、启动定时任务等
}

​​Web应用上下文中的实现示例​​：

@Override
protected void onRefresh() {// 调用父类实现super.onRefresh();try {// 初始化主题功能initThemeSource();// 初始化Servlet（如果是Web应用）initServlets();} catch (BeansException ex) {throw ex;} catch (Exception ex) {throw new ApplicationContextException("Failed to initialize context", ex);}
}

🔍 五、源码路径追踪：AbstractApplicationContext

📊 refresh() 方法执行流程图

​​完整的刷新流程可视化​​：

🔎 关键阶段源码深度分析

​​finishBeanFactoryInitialization() - 单例预实例化​​：

protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) {// 1. 初始化转换服务（用于类型转换）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));}// 2. 注册默认的字符串解析器if (!beanFactory.hasEmbeddedValueResolver()) {beanFactory.addEmbeddedValueResolver(strVal -> getEnvironment().resolvePlaceholders(strVal));}// 3. 初始化LoadTimeWeaver（AOP相关）String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false);for (String weaverAwareName : weaverAwareNames) {getBean(weaverAwareName);}// 4. 停止使用临时类加载器beanFactory.setTempClassLoader(null);// 5. 冻结所有Bean定义（不允许修改）beanFactory.freezeConfiguration();// 6. 急切地实例化所有非懒加载单例BeanbeanFactory.preInstantiateSingletons();
}

​​finishRefresh() - 完成刷新​​：

protected void finishRefresh() {// 1. 清除上下文级别的资源缓存clearResourceCaches();// 2. 初始化LifecycleProcessorinitLifecycleProcessor();// 3. 启动LifecycleProcessor（触发Lifecycle Bean的启动）getLifecycleProcessor().onRefresh();// 4. 发布ContextRefreshedEvent事件publishEvent(new ContextRefreshedEvent(this));// 5. 参与LiveBeansView（如果启用）LiveBeansView.registerApplicationContext(this);
}

🐛 六、调试日志与启动问题排查

📝 启动日志输出示例

​​完整的容器启动日志序列​​：

2024-01-15 10:30:15.123 INFO  - Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@1a2b3c4d
2024-01-15 10:30:15.124 DEBUG - Bean factory for AnnotationConfigApplicationContext: org.springframework.beans.factory.support.DefaultListableBeanFactory@5d6e7f82024-01-15 10:30:15.125 INFO  - Registering annotated classes: [com.example.AppConfig]
2024-01-15 10:30:15.126 DEBUG - Registered annotated class: com.example.AppConfig2024-01-15 10:30:15.127 INFO  - Overriding bean definition for bean 'userService' with a different definition
2024-01-15 10:30:15.128 DEBUG - Processing injected element of bean 'userService': AutowiredFieldElement for private UserRepository com.example.UserService.userRepository2024-01-15 10:30:15.129 INFO  - Creating shared instance of singleton bean 'userService'
2024-01-15 10:30:15.130 DEBUG - Creating instance of bean 'userService'
2024-01-15 10:30:15.131 DEBUG - Eagerly caching bean 'userService' to allow for resolving potential circular references2024-01-15 10:30:15.132 INFO  - Bean 'userService' of type [com.example.UserService] is not eligible for getting processed by all BeanPostProcessors
2024-01-15 10:30:15.133 DEBUG - Finished creating instance of bean 'userService'2024-01-15 10:30:15.134 INFO  - Publishing event in context: org.springframework.context.event.ContextRefreshedEvent[source=org.springframework.context.annotation.AnnotationConfigApplicationContext@1a2b3c4d]
2024-01-15 10:30:15.135 INFO  - Started ApplicationContext in 0.012 seconds (JVM running for 15.678)

🔧 调试技巧与工具

​​启动过程调试配置​​：

@Configuration
@Slf4j
public class StartupDebugConfig {/*** 启动过程监控Bean*/@Beanpublic StartupMonitor startupMonitor() {return new StartupMonitor();}/*** 自定义Bean后处理器用于调试*/@Beanpublic static BeanPostProcessor debugBeanPostProcessor() {return new DebugBeanPostProcessor();}
}/*** 启动监控器*/
@Component
@Slf4j
public class StartupMonitor implements ApplicationListener<ContextRefreshedEvent> {@Autowiredprivate ConfigurableApplicationContext context;@PostConstructpublic void init() {log.info("=== Spring容器启动监控器已初始化 ===");}@Overridepublic void onApplicationEvent(ContextRefreshedEvent event) {if (event.getApplicationContext() == context) {log.info("=== 容器启动完成，开始统计信息 ===");printBeanStatistics();printStartupTime();}}private void printBeanStatistics() {String[] beanNames = context.getBeanDefinitionNames();log.info("Bean定义总数: {}", beanNames.length);Map<String, Integer> beanTypeCount = new HashMap<>();for (String beanName : beanNames) {try {Object bean = context.getBean(beanName);String type = bean.getClass().getSimpleName();beanTypeCount.merge(type, 1, Integer::sum);} catch (Exception e) {// 忽略无法获取的Bean}}log.info("Bean类型分布: {}", beanTypeCount);}private void printStartupTime() {long startupDate = context.getStartupDate();long currentTime = System.currentTimeMillis();long duration = currentTime - startupDate;log.info("容器启动耗时: {}ms", duration);}
}/*** 调试用Bean后处理器*/
@Slf4j
public class DebugBeanPostProcessor implements BeanPostProcessor, Ordered {private final Set<String> processedBeans = ConcurrentHashMap.newKeySet();@Overridepublic int getOrder() {return Ordered.HIGHEST_PRECEDENCE;}@Overridepublic Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {if (processedBeans.add(beanName)) {log.debug("Bean初始化前: {} [{}]", beanName, bean.getClass().getSimpleName());}return bean;}@Overridepublic Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {log.debug("Bean初始化完成: {} [{}]", beanName, bean.getClass().getSimpleName());return bean;}
}

⚠️ 常见启动问题排查

​​循环依赖问题诊断​​：

@Component
public class CircularDependencyDetector {@Autowiredprivate ConfigurableListableBeanFactory beanFactory;public void detectCircularDependencies() {if (beanFactory instanceof DefaultListableBeanFactory) {DefaultListableBeanFactory dlbf = (DefaultListableBeanFactory) beanFactory;// 检查当前正在创建的BeanSet<String> beansInCreation = dlbf.getSingletonsCurrentlyInCreation();if (!beansInCreation.isEmpty()) {log.warn("当前正在创建的Bean: {}", beansInCreation);// 检查循环依赖for (String beanName : beansInCreation) {String[] dependentBeans = dlbf.getDependentBeans(beanName);String[] dependenciesForBean = dlbf.getDependenciesForBean(beanName);log.info("Bean '{}' 依赖的Bean: {}", beanName, Arrays.toString(dependenciesForBean));log.info("依赖 Bean '{}' 的Bean: {}", beanName, Arrays.toString(dependentBeans));}}}}
}

​​Bean定义冲突检测​​：

@Component
public class BeanDefinitionConflictDetector {@Autowiredprivate ConfigurableListableBeanFactory beanFactory;public void detectConflicts() {if (beanFactory instanceof DefaultListableBeanFactory) {DefaultListableBeanFactory dlbf = (DefaultListableBeanFactory) beanFactory;String[] beanNames = dlbf.getBeanDefinitionNames();Map<String, List<String>> typeToBeanNames = new HashMap<>();for (String beanName : beanNames) {BeanDefinition bd = dlbf.getBeanDefinition(beanName);String beanClassName = bd.getBeanClassName();if (beanClassName != null) {typeToBeanNames.computeIfAbsent(beanClassName, k -> new ArrayList<>()).add(beanName);}}// 报告冲突for (Map.Entry<String, List<String>> entry : typeToBeanNames.entrySet()) {if (entry.getValue().size() > 1) {log.warn("类型冲突: {} 被多个Bean定义使用: {}", entry.getKey(), entry.getValue());}}}}
}

💎 七、总结：Spring 容器的启动脉络

🎯 核心启动流程总结

​​Spring 容器刷新12个关键阶段​​：

阶段	方法	框架职责	核心动作 / 输出	业务扩展点
①	prepareRefresh()	容器预处理阶段	初始化环境属性源、校验必要配置、准备事件系统	可重写以自定义环境加载逻辑（如动态配置中心）
②	obtainFreshBeanFactory()	BeanFactory 创建	解析配置源（XML/注解），加载 BeanDefinition	自定义 BeanDefinitionReader
③	prepareBeanFactory()	BeanFactory 初始化	注册类加载器、环境 Bean、依赖注入基础设施	可注册自定义 Aware 接口或依赖注入策略
④	postProcessBeanFactory()	工厂后处理入口	留给子类定制（如 Web 容器增加 Theme、ServletContext）	常用于框架级容器扩展
⑤	invokeBeanFactoryPostProcessors()	处理 BeanDefinition	调用所有 BeanFactoryPostProcessor（含 ConfigurationClassPostProcessor）	扫描 @Configuration、@Bean、@Component 等配置
⑥	registerBeanPostProcessors()	Bean 生命周期拦截器注册	注册 BeanPostProcessor，用于 Bean 实例化前后增强	AOP、@Autowired、@Async 均依赖此机制
⑦	initMessageSource()	国际化支持	初始化 MessageSource，用于 i18n 文本解析	可替换为企业自定义多语言源
⑧	initApplicationEventMulticaster()	事件广播机制	初始化事件多播器（ApplicationEventMulticaster）	支持事件驱动架构
⑨	onRefresh()	模板方法扩展	留给子类（如 Web、Cloud）实现特定初始化	WebServer 启动点、Netty 初始化等
⑩	registerListeners()	注册事件监听器	注册所有 ApplicationListener，并广播早期事件	自定义事件系统可在此扩展
⑪	finishBeanFactoryInitialization()	Bean 实例化阶段	实例化所有非懒加载单例，触发依赖注入、初始化回调	BeanPostProcessor 开始工作
⑫	finishRefresh()	容器启动完成	发布 ContextRefreshedEvent，启动 Lifecycle Bean	Spring Boot 启动事件源（ApplicationReadyEvent）

🚀 性能优化建议

​​容器启动性能调优策略​​：

@Configuration
@Slf4j
public class StartupOptimizationConfig {/*** 1. 合理使用懒加载*/@Bean@Lazypublic HeavyResourceService heavyResourceService() {return new HeavyResourceService(); // 延迟初始化}/*** 2. 避免不必要的组件扫描*/@ComponentScan(basePackages = "com.example.core", // 精确指定包路径excludeFilters = @ComponentScan.Filter(type = FilterType.REGEX, pattern = ".*Test.*") // 排除测试类)public static class OptimizedScan {}/*** 3. 使用配置类索引加速扫描*/@Indexed@Configurationpublic static class IndexedConfig {// 编译时生成索引，加速组件扫描}/*** 4. 合理配置Bean作用域*/@Bean@Scope("prototype") // 原型作用域，避免不必要的单例初始化public StatefulService statefulService() {return new StatefulService();}
}

🔮 高级特性与最佳实践

​​容器启动事件监听​​：

@Component
@Slf4j
public class ComprehensiveStartupListener implements ApplicationContextAware, ApplicationListener<ApplicationEvent>, Ordered {private ApplicationContext applicationContext;@Overridepublic void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.applicationContext = applicationContext;log.info("ApplicationContext已设置: {}", applicationContext.getClass().getSimpleName());}@Overridepublic void onApplicationEvent(ApplicationEvent event) {// 监听各种启动事件if (event instanceof ContextRefreshedEvent) {log.info("✅ 容器刷新完成");performPostStartupActions();} else if (event instanceof ContextStartedEvent) {log.info("🚀 容器启动完成");} else if (event instanceof ContextStoppedEvent) {log.info("🛑 容器停止");} else if (event instanceof ContextClosedEvent) {log.info("🔚 容器关闭");}}private void performPostStartupActions() {// 启动后执行的任务log.info("执行启动后任务...");// 例如：初始化缓存、启动定时任务等initializeCaches();startScheduledTasks();}@Overridepublic int getOrder() {return Ordered.HIGHEST_PRECEDENCE;}
}