springboot启动源码解析

@SpringBootApplication
public class StartBootTestApplication {
    public static void main(String[] args) {
        //第一个参数为Spring容器配置类，第二个参数为命令行参数
        SpringApplication.run(StartBootTestApplication.class,args);
    }
}

/**
*SpringApplication
*/
//构造器初始化
public SpringApplication(ResourceLoader resourceLoader, Class... primarySources) {
this.sources = new LinkedHashSet();
//横幅模式 OFF,CONSOLE,LOG;
this.bannerMode = Mode.CONSOLE;
this.logStartupInfo = true;
this.addCommandLineProperties = true;
this.addConversionService = true;
this.headless = true;
this.registerShutdownHook = true;
this.additionalProfiles = new HashSet();
this.isCustomEnvironment = false;
this.resourceLoader = resourceLoader;
Assert.notNull(primarySources, "PrimarySources must not be null");
this.primarySources = new LinkedHashSet(Arrays.asList(primarySources));
//应用类型NONE,SERVLET,REACTIVE;存在DispatcherHandler，不存在DispatcherServlet，ServletContainer，则为REACTIVE
//不存在javax.servlet.Servlet", "org.springframework.web.context.ConfigurableWebApplicationContext，则为NONE，则为SERVLET
this.webApplicationType = WebApplicationType.deduceFromClasspath();
//spring.factories文件中org.springframework.context.ApplicationContextInitializer=//org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer,//org.springframework.boot.context.ContextIdApplicationContextInitializer,//org.springframework.boot.context.config.DelegatingApplicationContextInitializer,//org.springframework.boot.web.context.ServerPortInfoApplicationContextInitializer
this.setInitializers(this.getSpringFactoriesInstances(ApplicationContextInitializer.class));
//org.springframework.context.ApplicationListener=//org.springframework.boot.ClearCachesApplicationListener,//org.springframework.boot.builder.ParentContextCloserApplicationListener,//org.springframework.boot.context.FileEncodingApplicationListener,//org.springframework.boot.context.config.AnsiOutputApplicationListener,//org.springframework.boot.context.config.ConfigFileApplicationListener,//org.springframework.boot.context.config.DelegatingApplicationListener,//org.springframework.boot.context.logging.ClasspathLoggingApplicationListener,//org.springframework.boot.context.logging.LoggingApplicationListener,//org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener 进行初始化
this.setListeners(this.getSpringFactoriesInstances(ApplicationListener.class));
//推论出主类main
this.mainApplicationClass = this.deduceMainApplicationClass();
}

//核心开始运行
public ConfigurableApplicationContext run(String... args) {
//秒表，用于记录启动时间，记录每个任务 的时间，
StopWatch stopWatch = new StopWatch();
stopWatch.start();
//spring应用上下文，spring容器
ConfigurableApplicationContext context = null;
//自定义SpringApplication启动错误的回调接口
Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList();
//java.awt.headless模式 默认为true开启
this.configureHeadlessProperty();
//开启监听
//org.springframework.boot.SpringApplicationRunListener=//org.springframework.boot.context.event.EventPublishingRunListener
SpringApplicationRunListeners listeners = this.getRunListeners(args);
//
listeners.starting();

Collection exceptionReporters;
try {
//参数封装，在命令行下启动应用带的参数，如--server.port
ApplicationArguments applicationArguments = new DefaultApplicationArguments(args);
//环境准备 1.加载外部化配置的资源到environment 2.触发ApplicationEnvironmentPreparedEvent事件
ConfigurableEnvironment environment = this.prepareEnvironment(listeners, applicationArguments);
//配置系统属性spring.beaninfo.ignore
this.configureIgnoreBeanInfo(environment);
//打印横幅
Banner printedBanner = this.printBanner(environment);
//创建ApplicationContext 根据webApplicationType
//SERVLET:
// contextClass = Class.forName("org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext");
//REACTIVE:
// contextClass = Class.forName("org.springframework.boot.web.reactive.context.AnnotationConfigReactiveWebServerApplicationContext");
// default:
// contextClass = Class.forName("org.springframework.context.annotation.AnnotationConfigApplicationContext");
/**
*AnnotationConfigServletWebServerApplicationContext层级关系-》ServletWebServerApplicationContext-》GenericWebApplicationContext
*-》GenericApplicationContext-》AbstractApplicationContext
*/
//部分属性：reader、scanner、beanFactory进行了实例化
context = this.createApplicationContext();
//实例化 用来支持报告关于启动的错误
//# Error Reporters
//org.springframework.boot.SpringBootExceptionReporter=//org.springframework.boot.diagnostics.FailureAnalyzers
exceptionReporters = this.getSpringFactoriesInstances(SpringBootExceptionReporter.class, new Class[]{ConfigurableApplicationContext.class}, context);
//ApplicationContext准备 加载
this.prepareContext(context, environment, listeners, applicationArguments, printedBanner);
//核心：
this.refreshContext(context);
this.afterRefresh(context, applicationArguments);
stopWatch.stop();
if (this.logStartupInfo) {
(new StartupInfoLogger(this.mainApplicationClass)).logStarted(this.getApplicationLog(), stopWatch);
}

listeners.started(context);
this.callRunners(context, applicationArguments);
} catch (Throwable var10) {
this.handleRunFailure(context, var10, exceptionReporters, listeners);
throw new IllegalStateException(var10);
}

try {
listeners.running(context);
return context;
} catch (Throwable var9) {
this.handleRunFailure(context, var9, exceptionReporters, (SpringApplicationRunListeners)null);
throw new IllegalStateException(var9);
}
}

//环境准备
private ConfigurableEnvironment prepareEnvironment(SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments) {
//创建环境 SERVLET StandardServletEnvironment； REACTIVE StandardReactiveWebEnvironment； StandardEnvironment
ConfigurableEnvironment environment = this.getOrCreateEnvironment();
this.configureEnvironment((ConfigurableEnvironment)environment, applicationArguments.getSourceArgs());
listeners.environmentPrepared((ConfigurableEnvironment)environment);
this.bindToSpringApplication((ConfigurableEnvironment)environment);
if (!this.isCustomEnvironment) {
environment = (new EnvironmentConverter(this.getClassLoader())).convertEnvironmentIfNecessary((ConfigurableEnvironment)environment, this.deduceEnvironmentClass());
}

ConfigurationPropertySources.attach((Environment)environment);
return (ConfigurableEnvironment)environment;
}

//ApplicationContext准备 加载
private void prepareContext(ConfigurableApplicationContext context, ConfigurableEnvironment environment, SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments, Banner printedBanner) {
//设置上下文的environment
context.setEnvironment(environment);
//应用上下文后处理
this.postProcessApplicationContext(context);
//在context refresh之前，对其应用ApplicationContextInitializer
this.applyInitializers(context);
//上下文准备（目前是空实现，有待扩展）
listeners.contextPrepared(context);
//打印启动日志和启动应用profile
if (this.logStartupInfo) {
this.logStartupInfo(context.getParent() == null);
this.logStartupProfileInfo(context);
}
//向beanFactory注册单例bean：命令行参数bean
ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
beanFactory.registerSingleton("springApplicationArguments", applicationArguments);
if (printedBanner != null) {
//向beanFactory注册单例bean：banner bean 
beanFactory.registerSingleton("springBootBanner", printedBanner);
}

if (beanFactory instanceof DefaultListableBeanFactory) {
((DefaultListableBeanFactory)beanFactory).setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);
}

Set<Object> sources = this.getAllSources();
Assert.notEmpty(sources, "Sources must not be empty");
//把bean加载到应用上下文中
this.load(context, sources.toArray(new Object[0]));
//向上下文中添加applicationListener,并广播ApplicationPerpareEvent事件
listeners.contextLoaded(context);
}    

/**
*AbstractApplicationContext
*/ 
//刷新
public void refresh() throws BeansException, IllegalStateException {
Object var1 = this.startupShutdownMonitor;
synchronized(this.startupShutdownMonitor) {
//1.刷新前准备 校验
this.prepareRefresh();
//2.获取DefaultListableBeanFactory实例
ConfigurableListableBeanFactory beanFactory = this.obtainFreshBeanFactory();
//3.beanFactory加载配置
this.prepareBeanFactory(beanFactory);

try {
//4.BeanFactory准备工作完成后进行的后置准备工作
//beanFactory后置处理，重写ApplicationContext的postProcessBeanFactory方法 未做处理
this.postProcessBeanFactory(beanFactory);
/********以上是BeanFactory的创建及预准备工作********/

//核心：执行BeanFactoryPostProcessor的方法：
//BeanFactoryPostProcessor:BeanFactory的后置处理器，在BeanFactory标准初始化之后执行的；
//他的重要两个接口：BeanFactoryPostProcessor、BeanDefitionRegistryPostProcessor
this.invokeBeanFactoryPostProcessors(beanFactory);
//注册BeanPostProcessor(Bean的后置处理器)
this.registerBeanPostProcessors(beanFactory);
//7 初始化MessageSource组件（做国际化功能：消息绑定，消息解析）
this.initMessageSource();
//8初始化事件派发器
this.initApplicationEventMulticaster();
//9子类重写这个方法，在容器刷新的时候可以自定义逻辑
this.onRefresh();
//10.给容器中所有项目里面的ApplicationListener注册进来
this.registerListeners();
//11.初始化所有剩下的单实例bean
this.finishBeanFactoryInitialization(beanFactory);
//12.完成beanFactory的初始化创建工作：IOC容器就创建完成
this.finishRefresh();
} catch (BeansException var9) {
if (this.logger.isWarnEnabled()) {
this.logger.warn("Exception encountered during context initialization - cancelling refresh attempt: " + var9);
}

this.destroyBeans();
this.cancelRefresh(var9);
throw var9;
} finally {
this.resetCommonCaches();
}

}
} 

/**
*AbstractApplicationContext
*/ 
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
//1 设置BeanFactory的类加载器
beanFactory.setBeanClassLoader(this.getClassLoader());
//2 设置支持表达式解析器
beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, this.getEnvironment()));
//3 添加部分BeanPostProcessor
beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
//4 设置忽略的自动装配的接口EnvironmentAware、EmbeddedValueResolverAware、xxx;
//这些接口的实现类不能通过类型来自动注入
beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
//5 注册可以解析的自动装配：我们能直接在任何组件中自动注入：
//BeanFactory/ResourceLoader、ApplicationEventPublisher、ApplicationContext
//使用：
//@Autowired
//BeanFactory beanFactory
beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
beanFactory.registerResolvableDependency(ResourceLoader.class, this);
beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
beanFactory.registerResolvableDependency(ApplicationContext.class, this);
//6 添加BeanPostProcessor后置处理器
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));
//7 添加编译时AspectJ
if (beanFactory.containsBean("loadTimeWeaver")) {
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}
//8 注册组件
if (!beanFactory.containsLocalBean("environment")) {
beanFactory.registerSingleton("environment", this.getEnvironment());
}

if (!beanFactory.containsLocalBean("systemProperties")) {
beanFactory.registerSingleton("systemProperties", this.getEnvironment().getSystemProperties());
}

if (!beanFactory.containsLocalBean("systemEnvironment")) {
beanFactory.registerSingleton("systemEnvironment", this.getEnvironment().getSystemEnvironment());
}

}

/**
*AbstractApplicationContext
*/ 
//执行BeanFactoryPostProcessor的后置处理器方法
protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, this.getBeanFactoryPostProcessors());
if (beanFactory.getTempClassLoader() == null && beanFactory.containsBean("loadTimeWeaver")) {
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}

}

/**
*PostProcessorRegistrationDelegate

*/
public static void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {
Set<String> processedBeans = new HashSet();
ArrayList regularPostProcessors;
ArrayList registryProcessors;
int var9;
ArrayList currentRegistryProcessors;
String[] postProcessorNames;
//1.判断beanFactory是否为BeanDefinitionRegistry，beanFactory为DefaultListableBeanFactory，
//而DefaultListableBeanFactory实现了BeanDefinitionRegistry接口
if (beanFactory instanceof BeanDefinitionRegistry) {
//强转成BeanDefinitionRegistry
BeanDefinitionRegistry registry = (BeanDefinitionRegistry)beanFactory;
//保存BeanFactoryPostProcessor类型的后置处理器
regularPostProcessors = new ArrayList();
//保存BeanDefinitionRegistryPostProcessor类型的后置处理器
registryProcessors = new ArrayList();
Iterator var6 = beanFactoryPostProcessors.iterator();
//循环遍历beanFactoryPostProcessors
while(var6.hasNext()) {
BeanFactoryPostProcessor postProcessor = (BeanFactoryPostProcessor)var6.next();
//判断是否BeanDefinitionRegistryPostProcessor
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
//强转BeanDefinitionRegistryPostProcessor
BeanDefinitionRegistryPostProcessor registryProcessor = (BeanDefinitionRegistryPostProcessor)postProcessor;
//调用后置方法
registryProcessor.postProcessBeanDefinitionRegistry(registry);
//添加到集合当中
registryProcessors.add(registryProcessor);
} else {
//没有实现BeanDefinitionRegistryPostProcessor接口，添加到regularPostProcessors集合中
regularPostProcessors.add(postProcessor);
}
}
//定义一个集合保存当前准备创建的BeanDefinitionRegistryPostProcessor
currentRegistryProcessors = new ArrayList();
//第一步：去容器中获取BeanDefinitionRegistryPostProcessor的bean的处理器名称
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
String[] var16 = postProcessorNames;
var9 = postProcessorNames.length;

int var10;
String ppName;
//循环遍历获取BeanDefinitionRegistryPostProcessor的类型名称
for(var10 = 0; var10 < var9; ++var10) {
ppName = var16[var10];
//判断是否实现了PriorityOrdered接口
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
//调用getBean方法获取该对象加入currentRegistryProcessors集合中
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
//同时加入processedBeans集合中
processedBeans.add(ppName);
}
}
//对currentRegistryProcessors集合中BeanDefinitionRegistryPostProcessor进行排序
sortPostProcessors(currentRegistryProcessors, beanFactory);
//保存到registryProcessors中
registryProcessors.addAll(currentRegistryProcessors);
/**
*核心：典型的BeanDefinitionRegistryPostProcessor是ConfigurationClassPostProcessor
*用于进行bean定义的加载 ->processConfigBeanDefinitions方法
*/
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
//1清除当前临时集合currentRegistryProcessors
currentRegistryProcessors.clear();
//又在容器中获取BeanDefinitionRegistryPostProcessor的bean处理器名称
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
var16 = postProcessorNames;
var9 = postProcessorNames.length;

for(var10 = 0; var10 < var9; ++var10) {
ppName = var16[var10];
//没被处理过 且实现了Ordered接口
if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {
//调用getBean方法获取该对象加入currentRegistryProcessors集合中
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
//同时加入processedBeans集合中
processedBeans.add(ppName);
}
}
//对currentRegistryProcessors集合中BeanDefinitionRegistryPostProcessor进行排序
sortPostProcessors(currentRegistryProcessors, beanFactory);
//保存到registryProcessors中
registryProcessors.addAll(currentRegistryProcessors);
//调用后置处理方法
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
//2清除当前临时集合currentRegistryProcessors
currentRegistryProcessors.clear();
boolean reiterate = true;
//调用没有实现任何优先级接口的BeanDefinitionRegistryPostProcessor
while(reiterate) {
//进入循环把reiterate更新为false
reiterate = false;
//在容器中获取BeanDefinitionRegistryPostProcessor的bean处理器名称
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
String[] var19 = postProcessorNames;
var10 = postProcessorNames.length;

for(int var26 = 0; var26 < var10; ++var26) {
String ppName = var19[var26];
//没有被处理过的
if (!processedBeans.contains(ppName)) {
//调用getBean方法获取该对象加入currentRegistryProcessors集合中
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
//同时加入processedBeans集合中
processedBeans.add(ppName);

reiterate = true;
}
}
////对currentRegistryProcessors集合中BeanDefinitionRegistryPostProcessor进行排序
sortPostProcessors(currentRegistryProcessors, beanFactory);
//保存到registryProcessors中
registryProcessors.addAll(currentRegistryProcessors);
//调用后置处理方法
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
//3清除当前临时集合currentRegistryProcessors
currentRegistryProcessors.clear();
}
//调用实现了BeanDefinitionRegistryPostProcessor接口和BeanFactoryPostProcessor接口的方法
invokeBeanFactoryPostProcessors((Collection)registryProcessors, (ConfigurableListableBeanFactory)beanFactory);
//调用实现了BeanFactoryPostProcessor接口的方法
invokeBeanFactoryPostProcessors((Collection)regularPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
} else {
//beanFactory没有实现了BeanDefinitionRegistry 直接调用beanFactoryPostProcessor接口的方法进行后置处理器
invokeBeanFactoryPostProcessors((Collection)beanFactoryPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
}
//最后 获取容器中所有的BeanFactoryPostProcessor
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
//保存实现了priorityOrdered接口
regularPostProcessors = new ArrayList();
//保存实现了Ordered接口
registryProcessors = new ArrayList();
currentRegistryProcessors = new ArrayList();
postProcessorNames = postProcessorNames;//错误代码
int var20 = postProcessorNames.length;

String ppName;
for(var9 = 0; var9 < var20; ++var9) {
ppName = postProcessorNames[var9];
//没被处理过
if (!processedBeans.contains(ppName)) {
//判断是否实现了PriorityOrdered
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
regularPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
//判断是否实现了Ordered
} else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
registryProcessors.add(ppName);
} else {
//没有任何优先级接口
currentRegistryProcessors.add(ppName);
}
}
}

sortPostProcessors(regularPostProcessors, beanFactory);
//先调用BeanFactoryPostProcessor实现了priorityOrdered接口
invokeBeanFactoryPostProcessors((Collection)regularPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList();
Iterator var21 = registryProcessors.iterator();

while(var21.hasNext()) {
String postProcessorName = (String)var21.next();
orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
//再调用BeanFactoryPostProcessor实现了Ordered接口
sortPostProcessors(orderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors((Collection)orderedPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList();
Iterator var24 = currentRegistryProcessors.iterator();

while(var24.hasNext()) {
ppName = (String)var24.next();
nonOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
}
//最后调用没有实现任何方法接口
invokeBeanFactoryPostProcessors((Collection)nonOrderedPostProcessors, (ConfigurableListableBeanFactory)beanFactory);
beanFactory.clearMetadataCache();
}

/**
*ConfigurationClassPostProcessor
*
*/    
public void processConfigBeanDefinitions(BeanDefinitionRegistry registry) {
//
List<BeanDefinitionHolder> configCandidates = new ArrayList();
//获取springIOC容器中目前所有bean定义的名称
String[] candidateNames = registry.getBeanDefinitionNames();
String[] var4 = candidateNames;
int var5 = candidateNames.length;
//循环所有的Bean定义信息
for(int var6 = 0; var6 < var5; ++var6) {
String beanName = var4[var6];
//通过bean的名称来获取bean的定义对象
BeanDefinition beanDef = registry.getBeanDefinition(beanName);
//判断是否解析过
if (!ConfigurationClassUtils.isFullConfigurationClass(beanDef) && !ConfigurationClassUtils.isLiteConfigurationClass(beanDef)) {
//判读是否是配置类
if (ConfigurationClassUtils.checkConfigurationClassCandidate(beanDef, this.metadataReaderFactory)) {
//添加到候选的配置类集合中
configCandidates.add(new BeanDefinitionHolder(beanDef, beanName));
}
} else if (this.logger.isDebugEnabled()) {
this.logger.debug("Bean definition has already been processed as a configuration class: " + beanDef);
}
}

if (!configCandidates.isEmpty()) {
//对配置类进行Order排序
configCandidates.sort((bd1, bd2) -> {
int i1 = ConfigurationClassUtils.getOrder(bd1.getBeanDefinition());
int i2 = ConfigurationClassUtils.getOrder(bd2.getBeanDefinition());
return Integer.compare(i1, i2);
});
//创建@CompentScan、@Import导入进来的bean名称的生成器
SingletonBeanRegistry sbr = null;
if (registry instanceof SingletonBeanRegistry) {
sbr = (SingletonBeanRegistry)registry;
if (!this.localBeanNameGeneratorSet) {
BeanNameGenerator generator = (BeanNameGenerator)sbr.getSingleton("org.springframework.context.annotation.internalConfigurationBeanNameGenerator");
if (generator != null) {
//设置@CompentScan导入进来的bean的名称生成器
this.componentScanBeanNameGenerator = generator;
//设置@Import导入进来的bean的名称生成器
this.importBeanNameGenerator = generator;
}
}
}

if (this.environment == null) {
this.environment = new StandardEnvironment();
}
//创建配置类解析器对象
ConfigurationClassParser parser = new ConfigurationClassParser(this.metadataReaderFactory, this.problemReporter, this.environment, this.resourceLoader, this.componentScanBeanNameGenerator, registry);
//创建集合用于保存我们的配置类BeanDefinitionHolder集合默认长度是配置类集合的长度
Set<BeanDefinitionHolder> candidates = new LinkedHashSet(configCandidates);
//创建集合用于保存已经解析的配置类，长度默认解析出来配置类的集合长度
HashSet alreadyParsed = new HashSet(configCandidates.size());

do {
//真正解析配置类
/**
*核心解析：ConfigurationClassParser->parse
*/
parser.parse(candidates);
parser.validate();
//解析出来的配置类
Set<ConfigurationClass> configClasses = new LinkedHashSet(parser.getConfigurationClasses());
configClasses.removeAll(alreadyParsed);
if (this.reader == null) {
this.reader = new ConfigurationClassBeanDefinitionReader(registry, this.sourceExtractor, this.resourceLoader, this.environment, this.importBeanNameGenerator, parser.getImportRegistry());
}
//把解析出的配置类注册到容器中
this.reader.loadBeanDefinitions(configClasses);
//加入已经解析出的集合
alreadyParsed.addAll(configClasses);
candidates.clear();
//判断我们springIOC容器中Bean的定义数量是否大于候选原始的bean定义的个数
if (registry.getBeanDefinitionCount() > candidateNames.length) {
//获取所有bean的定义
String[] newCandidateNames = registry.getBeanDefinitionNames();
//原始的老的候选的bean定义
Set<String> oldCandidateNames = new HashSet(Arrays.asList(candidateNames));
Set<String> alreadyParsedClasses = new HashSet();
Iterator var12 = alreadyParsed.iterator();

while(var12.hasNext()) {
//添加已解析的
ConfigurationClass configurationClass = (ConfigurationClass)var12.next();
alreadyParsedClasses.add(configurationClass.getMetadata().getClassName());
}

String[] var23 = newCandidateNames;
int var24 = newCandidateNames.length;

for(int var14 = 0; var14 < var24; ++var14) {
String candidateName = var23[var14];
//当前还没有被解析过
if (!oldCandidateNames.contains(candidateName)) {
BeanDefinition bd = registry.getBeanDefinition(candidateName);
//判断有没有被解析过
if (ConfigurationClassUtils.checkConfigurationClassCandidate(bd, this.metadataReaderFactory) && !alreadyParsedClasses.contains(bd.getBeanClassName())) {
candidates.add(new BeanDefinitionHolder(bd, candidateName));
}
}
}

candidateNames = newCandidateNames;
}
//存在没有解析过的，需循环解析
} while(!candidates.isEmpty());

if (sbr != null && !sbr.containsSingleton(IMPORT_REGISTRY_BEAN_NAME)) {
sbr.registerSingleton(IMPORT_REGISTRY_BEAN_NAME, parser.getImportRegistry());
}

if (this.metadataReaderFactory instanceof CachingMetadataReaderFactory) {
((CachingMetadataReaderFactory)this.metadataReaderFactory).clearCache();
}

}
}

/**
*ConfigurationClassParser
*/    
public void parse(Set<BeanDefinitionHolder> configCandidates) {
Iterator var2 = configCandidates.iterator();

while(var2.hasNext()) {
BeanDefinitionHolder holder = (BeanDefinitionHolder)var2.next();
BeanDefinition bd = holder.getBeanDefinition();

try {
//真正的解析bean定义
if (bd instanceof AnnotatedBeanDefinition) {
this.parse(((AnnotatedBeanDefinition)bd).getMetadata(), holder.getBeanName());
} else if (bd instanceof AbstractBeanDefinition && ((AbstractBeanDefinition)bd).hasBeanClass()) {
this.parse(((AbstractBeanDefinition)bd).getBeanClass(), holder.getBeanName());
} else {
this.parse(bd.getBeanClassName(), holder.getBeanName());
}
} catch (BeanDefinitionStoreException var6) {
throw var6;
} catch (Throwable var7) {
throw new BeanDefinitionStoreException("Failed to parse configuration class [" + bd.getBeanClassName() + "]", var7);
}
}
//处理延时的DeferredImportSelectors spring boot 是通过这步进行spring.factories文件中的自定装配的对象
this.deferredImportSelectorHandler.process();
}

protected final void parse(AnnotationMetadata metadata, String beanName) throws IOException {
//把我们配置类源信息和beanName包装成一个ConfigurationClass对象
this.processConfigurationClass(new ConfigurationClass(metadata, beanName));
}

protected void processConfigurationClass(ConfigurationClass configClass) throws IOException {
if (!this.conditionEvaluator.shouldSkip(configClass.getMetadata(), ConfigurationPhase.PARSE_CONFIGURATION)) {
//获取配置类对象
ConfigurationClass existingClass = (ConfigurationClass)this.configurationClasses.get(configClass);
if (existingClass != null) {
//传入的配置类是通过其他配置类的Import导入进来
if (configClass.isImported()) {
if (existingClass.isImported()) {
//合并配置
existingClass.mergeImportedBy(configClass);
}

return;
}

this.configurationClasses.remove(configClass);
this.knownSuperclasses.values().removeIf(configClass::equals);
}

ConfigurationClassParser.SourceClass sourceClass = this.asSourceClass(configClass);

do {
//解析配置类
sourceClass = this.doProcessConfigurationClass(configClass, sourceClass);
} while(sourceClass != null);

this.configurationClasses.put(configClass, configClass);
}
}

@Nullable
protected final ConfigurationClassParser.SourceClass doProcessConfigurationClass(ConfigurationClass configClass, ConfigurationClassParser.SourceClass sourceClass) throws IOException {
if (configClass.getMetadata().isAnnotated(Component.class.getName())) {
this.processMemberClasses(configClass, sourceClass);
}
//处理@PropertySources注解的
Iterator var3 = AnnotationConfigUtils.attributesForRepeatable(sourceClass.getMetadata(), PropertySources.class, PropertySource.class).iterator();

AnnotationAttributes importResource;
while(var3.hasNext()) {
importResource = (AnnotationAttributes)var3.next();
if (this.environment instanceof ConfigurableEnvironment) {
this.processPropertySource(importResource);
} else {
this.logger.info("Ignoring @PropertySource annotation on [" + sourceClass.getMetadata().getClassName() + "]. Reason: Environment must implement ConfigurableEnvironment");
}
}
//处理@ComponentScans注解的
Set<AnnotationAttributes> componentScans = AnnotationConfigUtils.attributesForRepeatable(sourceClass.getMetadata(), ComponentScans.class, ComponentScan.class);
if (!componentScans.isEmpty() && !this.conditionEvaluator.shouldSkip(sourceClass.getMetadata(), ConfigurationPhase.REGISTER_BEAN)) {
Iterator var13 = componentScans.iterator();

while(var13.hasNext()) {
AnnotationAttributes componentScan = (AnnotationAttributes)var13.next();
/**
*ComponentScanAnnotationParser->parse
*/
Set<BeanDefinitionHolder> scannedBeanDefinitions = this.componentScanParser.parse(componentScan, sourceClass.getMetadata().getClassName());
Iterator var7 = scannedBeanDefinitions.iterator();

while(var7.hasNext()) {
BeanDefinitionHolder holder = (BeanDefinitionHolder)var7.next();
BeanDefinition bdCand = holder.getBeanDefinition().getOriginatingBeanDefinition();
if (bdCand == null) {
bdCand = holder.getBeanDefinition();
}
//判断当前扫描出来的bean定义是不是配置类，是，进行递归解析
if (ConfigurationClassUtils.checkConfigurationClassCandidate(bdCand, this.metadataReaderFactory)) {
//递归解析
this.parse(bdCand.getBeanClassName(), holder.getBeanName());
}
}
}
}
//处理@Import
this.processImports(configClass, sourceClass, this.getImports(sourceClass), true);
//处理@ImportResource
importResource = AnnotationConfigUtils.attributesFor(sourceClass.getMetadata(), ImportResource.class);
if (importResource != null) {
String[] resources = importResource.getStringArray("locations");
Class<? extends BeanDefinitionReader> readerClass = importResource.getClass("reader");
String[] var19 = resources;
int var21 = resources.length;

for(int var22 = 0; var22 < var21; ++var22) {
String resource = var19[var22];
String resolvedResource = this.environment.resolveRequiredPlaceholders(resource);
configClass.addImportedResource(resolvedResource, readerClass);
}
}
//处理@Bean methods获取到我们配置类中所有标注了@Bean的方法
Set<MethodMetadata> beanMethods = this.retrieveBeanMethodMetadata(sourceClass);
Iterator var17 = beanMethods.iterator();

while(var17.hasNext()) {
MethodMetadata methodMetadata = (MethodMetadata)var17.next();
configClass.addBeanMethod(new BeanMethod(methodMetadata, configClass));
}
//处理配置类接口
this.processInterfaces(configClass, sourceClass);
//处理配置类的父类
if (sourceClass.getMetadata().hasSuperClass()) {
String superclass = sourceClass.getMetadata().getSuperClassName();
if (superclass != null && !superclass.startsWith("java") && !this.knownSuperclasses.containsKey(superclass)) {
this.knownSuperclasses.put(superclass, configClass);
return sourceClass.getSuperClass();
}
}

return null;
}

/**
*ComponentScanAnnotationParser
*/    
public Set<BeanDefinitionHolder> parse(AnnotationAttributes componentScan, final String declaringClass) {
ClassPathBeanDefinitionScanner scanner = new ClassPathBeanDefinitionScanner(this.registry, componentScan.getBoolean("useDefaultFilters"), this.environment, this.resourceLoader);
//给扫描器设置beanName的生成器对象
Class<? extends BeanNameGenerator> generatorClass = componentScan.getClass("nameGenerator");
boolean useInheritedGenerator = BeanNameGenerator.class == generatorClass;
scanner.setBeanNameGenerator(useInheritedGenerator ? this.beanNameGenerator : (BeanNameGenerator)BeanUtils.instantiateClass(generatorClass));
//设置bean的域代理模型
ScopedProxyMode scopedProxyMode = (ScopedProxyMode)componentScan.getEnum("scopedProxy");
if (scopedProxyMode != ScopedProxyMode.DEFAULT) {
scanner.setScopedProxyMode(scopedProxyMode);
} else {
Class<? extends ScopeMetadataResolver> resolverClass = componentScan.getClass("scopeResolver");
scanner.setScopeMetadataResolver((ScopeMetadataResolver)BeanUtils.instantiateClass(resolverClass));
}

scanner.setResourcePattern(componentScan.getString("resourcePattern"));
//设置ComponentScan对象的includeFilters包含的属性
AnnotationAttributes[] var15 = componentScan.getAnnotationArray("includeFilters");
int var8 = var15.length;

int var9;
AnnotationAttributes filter;
Iterator var11;
TypeFilter typeFilter;
for(var9 = 0; var9 < var8; ++var9) {
filter = var15[var9];
var11 = this.typeFiltersFor(filter).iterator();

while(var11.hasNext()) {
typeFilter = (TypeFilter)var11.next();
scanner.addIncludeFilter(typeFilter);
}
}
//设置ComponentScan对象的excludeFilters不包含的属性
var15 = componentScan.getAnnotationArray("excludeFilters");
var8 = var15.length;

for(var9 = 0; var9 < var8; ++var9) {
filter = var15[var9];
var11 = this.typeFiltersFor(filter).iterator();

while(var11.hasNext()) {
typeFilter = (TypeFilter)var11.next();
scanner.addExcludeFilter(typeFilter);
}
}
//是否懒加载
boolean lazyInit = componentScan.getBoolean("lazyInit");
if (lazyInit) {
scanner.getBeanDefinitionDefaults().setLazyInit(true);
}
//包路径
Set<String> basePackages = new LinkedHashSet();
String[] basePackagesArray = componentScan.getStringArray("basePackages");
String[] var19 = basePackagesArray;
int var21 = basePackagesArray.length;

int var22;
for(var22 = 0; var22 < var21; ++var22) {
String pkg = var19[var22];
String[] tokenized = StringUtils.tokenizeToStringArray(this.environment.resolvePlaceholders(pkg), ",; \t\n");
Collections.addAll(basePackages, tokenized);
}

Class[] var20 = componentScan.getClassArray("basePackageClasses");
var21 = var20.length;

for(var22 = 0; var22 < var21; ++var22) {
Class<?> clazz = var20[var22];
basePackages.add(ClassUtils.getPackageName(clazz));
}

if (basePackages.isEmpty()) {
basePackages.add(ClassUtils.getPackageName(declaringClass));
}

scanner.addExcludeFilter(new AbstractTypeHierarchyTraversingFilter(false, false) {
protected boolean matchClassName(String className) {
return declaringClass.equals(className);
}
});
//真正的进行扫描解析
return scanner.doScan(StringUtils.toStringArray(basePackages));
}