1. The entry program of springboot
@SpringBootApplication
public class StartupApplication {
public static void main(String[] args) {
SpringApplication.run(StartupApplication.class, args);
}
}
When the program starts to execute, it will call the construction method of SpringApplication to set some initial parameters
//创建一个新的实例，这个应用程序的上下文将要从指定的来源加载Bean
public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) {
//资源初始化资源加载器，默认为null
this.resourceLoader = resourceLoader;
//断言主要加载资源类不能为 null，否则报错
Assert.notNull(primarySources, "PrimarySources must not be null");
//初始化主要加载资源类集合并去重
this.primarySources = new LinkedHashSet<>(Arrays.asList(primarySources));
//推断当前 WEB 应用类型，一共有三种：NONE,SERVLET,REACTIVE
this.webApplicationType = WebApplicationType.deduceFromClasspath();
//设置应用上线文初始化器,从"META-INF/spring.factories"读取ApplicationContextInitializer类的实例名称集合并去重，并进行set去重。（一共7个）
setInitializers((Collection) getSpringFactoriesInstances(ApplicationContextInitializer.class));
//设置监听器,从"META-INF/spring.factories"读取ApplicationListener类的实例名称集合并去重，并进行set去重。（一共11个）
setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
//推断主入口应用类，通过当前调用栈，获取Main方法所在类，并赋值给mainApplicationClass
this.mainApplicationClass = deduceMainApplicationClass();
}
In the above construction method, there is a method to determine the application type, which is used to determine the type of the current application:
static WebApplicationType deduceFromClasspath() {
if (ClassUtils.isPresent(WEBFLUX_INDICATOR_CLASS, null) && !ClassUtils.isPresent(WEBMVC_INDICATOR_CLASS, null)
&& !ClassUtils.isPresent(JERSEY_INDICATOR_CLASS, null)) {
return WebApplicationType.REACTIVE;
}
for (String className : SERVLET_INDICATOR_CLASSES) {
if (!ClassUtils.isPresent(className, null)) {
return WebApplicationType.NONE;
}
}
return WebApplicationType.SERVLET;
}
//WebApplicationType的类型
public enum WebApplicationType {
/**
* The application should not run as a web application and should not start an
* embedded web server.
* 非web项目
*/
NONE,
/**
* The application should run as a servlet-based web application and should start an
* embedded servlet web server.
* servlet web 项目
*/
SERVLET,
/**
* The application should run as a reactive web application and should start an
* embedded reactive web server.
* 响应式 web 项目
*/
REACTIVE;
The running method of springboot startup, you can see that it is mainly the preparation of various operating environments
public ConfigurableApplicationContext run(String... args) {
//1、创建并启动计时监控类
StopWatch stopWatch = new StopWatch();
stopWatch.start();
//2、初始化应用上下文和异常报告集合
ConfigurableApplicationContext context = null;
Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();
//3、设置系统属性“java.awt.headless”的值，默认为true，用于运行headless服务器，进行简单的图像处理，多用于在缺少显示屏、键盘或者鼠标时的系统配置，很多监控工具如jconsole 需要将该值设置为true
configureHeadlessProperty();
//4、创建所有spring运行监听器并发布应用启动事件，简单说的话就是获取SpringApplicationRunListener类型的实例（EventPublishingRunListener对象），并封装进SpringApplicationRunListeners对象，然后返回这个SpringApplicationRunListeners对象。说的再简单点，getRunListeners就是准备好了运行时监听器EventPublishingRunListener。
SpringApplicationRunListeners listeners = getRunListeners(args);
listeners.starting();
try {
//5、初始化默认应用参数类
ApplicationArguments applicationArguments = new DefaultApplicationArguments(args);
//6、根据运行监听器和应用参数来准备spring环境
ConfigurableEnvironment environment = prepareEnvironment(listeners, applicationArguments);
//将要忽略的bean的参数打开
configureIgnoreBeanInfo(environment);
//7、创建banner打印类
Banner printedBanner = printBanner(environment);
//8、创建应用上下文，可以理解为创建一个容器
context = createApplicationContext();
//9、准备异常报告器，用来支持报告关于启动的错误
exceptionReporters = getSpringFactoriesInstances(SpringBootExceptionReporter.class,
new Class[] {
ConfigurableApplicationContext.class }, context);
//10、准备应用上下文，该步骤包含一个非常关键的操作，将启动类注入容器，为后续开启自动化提供基础
prepareContext(context, environment, listeners, applicationArguments, printedBanner);
//11、刷新应用上下文
refreshContext(context);
//12、应用上下文刷新后置处理，做一些扩展功能
afterRefresh(context, applicationArguments);
//13、停止计时监控类
stopWatch.stop();
//14、输出日志记录执行主类名、时间信息
if (this.logStartupInfo) {
new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), stopWatch);
}
//15、发布应用上下文启动监听事件
listeners.started(context);
//16、执行所有的Runner运行器
callRunners(context, applicationArguments);
}catch (Throwable ex) {
handleRunFailure(context, ex, exceptionReporters, listeners);
throw new IllegalStateException(ex);
}
try {
//17、发布应用上下文就绪事件
listeners.running(context);
}catch (Throwable ex) {
handleRunFailure(context, ex, exceptionReporters, null);
throw new IllegalStateException(ex);
}
//18、返回应用上下文
return context;
}
The following is a detailed introduction to each startup link:
1. Create and start the timing monitoring class, you can see the name of the recorded current task, the default is an empty string, and then record the start time of the current springboot application startup.
StopWatch stopWatch = new StopWatch();
stopWatch.start();
//详细源代码
public void start() throws IllegalStateException {
start("");
}
public void start(String taskName) throws IllegalStateException {
if (this.currentTaskName != null) {
throw new IllegalStateException("Can't start StopWatch: it's already running");
}
this.currentTaskName = taskName;
this.startTimeNanos = System.nanoTime();
}
2. Initialize the application context and exception report collection
ConfigurableApplicationContext context = null;
Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();
3. Set the value of the system property java.awt.headless:
/*
java.awt.headless模式是在缺少显示屏、键盘或者鼠标的系统配置
当配置了如下属性之后，应用程序可以执行如下操作：
1、创建轻量级组件
2、收集关于可用的字体、字体指标和字体设置的信息
3、设置颜色来渲染准备图片
4、创造和获取图像，为渲染准备图片
5、使用java.awt.PrintJob,java.awt.print.*和javax.print.*类里的方法进行打印
*/
private void configureHeadlessProperty() {
System.setProperty(SYSTEM_PROPERTY_JAVA_AWT_HEADLESS,
System.getProperty(SYSTEM_PROPERTY_JAVA_AWT_HEADLESS, Boolean.toString(this.headless)));
}
4. Create all spring running listeners and publish application startup events
SpringApplicationRunListeners listeners = getRunListeners(args);
listeners.starting();
//创建spring监听器
private SpringApplicationRunListeners getRunListeners(String[] args) {
Class<?>[] types = new Class<?>[] {
SpringApplication.class, String[].class };
return new SpringApplicationRunListeners(logger,
getSpringFactoriesInstances(SpringApplicationRunListener.class, types, this, args));
}
SpringApplicationRunListeners(Log log, Collection<? extends SpringApplicationRunListener> listeners) {
this.log = log;
this.listeners = new ArrayList<>(listeners);
}
//循环遍历获取监听器
void starting() {
for (SpringApplicationRunListener listener : this.listeners) {
listener.starting();
}
}
//此处的监听器可以看出是事件发布监听器，主要用来发布启动事件
@Override
public void starting() {
//这里是创建application事件‘applicationStartingEvent’
this.initialMulticaster.multicastEvent(new ApplicationStartingEvent(this.application, this.args));
}
//applicationStartingEvent是springboot框架最早执行的监听器，在该监听器执行started方法时，会继续发布事件，主要是基于spring的事件机制
@Override
public void multicastEvent(final ApplicationEvent event, @Nullable ResolvableType eventType) {
ResolvableType type = (eventType != null ? eventType : resolveDefaultEventType(event));
//获取线程池，如果为空则同步处理。这里线程池为空，还未初始化
Executor executor = getTaskExecutor();
for (ApplicationListener<?> listener : getApplicationListeners(event, type)) {
if (executor != null) {
//异步发送事件
executor.execute(() -> invokeListener(listener, event));
}
else {
//同步发送事件
invokeListener(listener, event);
}
}
}
5. Initialize the default application parameter class
ApplicationArguments applicationArguments = new DefaultApplicationArguments(args);
public DefaultApplicationArguments(String... args) {
Assert.notNull(args, "Args must not be null");
this.source = new Source(args);
this.args = args;
}
6. Prepare the spring environment according to the running listener and application parameters
ConfigurableEnvironment environment = prepareEnvironment(listeners, applicationArguments);
//详细环境的准备
private ConfigurableEnvironment prepareEnvironment(SpringApplicationRunListeners listeners,
ApplicationArguments applicationArguments) {
// 获取或者创建应用环境
ConfigurableEnvironment environment = getOrCreateEnvironment();
// 配置应用环境，配置propertySource和activeProfiles
configureEnvironment(environment, applicationArguments.getSourceArgs());
//listeners环境准备，广播ApplicationEnvironmentPreparedEvent
ConfigurationPropertySources.attach(environment);
listeners.environmentPrepared(environment);
//将环境绑定给当前应用程序
bindToSpringApplication(environment);
//对当前的环境类型进行判断，如果不一致进行转换
if (!this.isCustomEnvironment) {
environment = new EnvironmentConverter(getClassLoader()).convertEnvironmentIfNecessary(environment,
deduceEnvironmentClass());
}
//配置propertySource对它自己的递归依赖
ConfigurationPropertySources.attach(environment);
return environment;
}
// 获取或者创建应用环境，根据应用程序的类型可以分为servlet环境、标准环境(特殊的非web环境)和响应式环境
private ConfigurableEnvironment getOrCreateEnvironment() {
//存在则直接返回
if (this.environment != null) {
return this.environment;
}
//根据webApplicationType创建对应的Environment
switch (this.webApplicationType) {
case SERVLET:
return new StandardServletEnvironment();
case REACTIVE:
return new StandardReactiveWebEnvironment();
default:
return new StandardEnvironment();
}
}
//配置应用环境
protected void configureEnvironment(ConfigurableEnvironment environment, String[] args) {
if (this.addConversionService) {
ConversionService conversionService = ApplicationConversionService.getSharedInstance();
environment.setConversionService((ConfigurableConversionService) conversionService);
}
//配置property sources
configurePropertySources(environment, args);
//配置profiles
configureProfiles(environment, args);
}
7. Create a banner printing class
Banner printedBanner = printBanner(environment);
//打印类的详细操作过程
private Banner printBanner(ConfigurableEnvironment environment) {
if (this.bannerMode == Banner.Mode.OFF) {
return null;
}
ResourceLoader resourceLoader = (this.resourceLoader != null) ? this.resourceLoader
: new DefaultResourceLoader(getClassLoader());
SpringApplicationBannerPrinter bannerPrinter = new SpringApplicationBannerPrinter(resourceLoader, this.banner);
if (this.bannerMode == Mode.LOG) {
return bannerPrinter.print(environment, this.mainApplicationClass, logger);
}
return bannerPrinter.print(environment, this.mainApplicationClass, System.out);
}
8. Create application context: initialize different context application classes according to different application types
context = createApplicationContext();
protected ConfigurableApplicationContext createApplicationContext() {
Class<?> contextClass = this.applicationContextClass;
if (contextClass == null) {
try {
switch (this.webApplicationType) {
case SERVLET:
contextClass = Class.forName(DEFAULT_SERVLET_WEB_CONTEXT_CLASS);
break;
case REACTIVE:
contextClass = Class.forName(DEFAULT_REACTIVE_WEB_CONTEXT_CLASS);
break;
default:
contextClass = Class.forName(DEFAULT_CONTEXT_CLASS);
}
}
catch (ClassNotFoundException ex) {
throw new IllegalStateException(
"Unable create a default ApplicationContext, please specify an ApplicationContextClass", ex);
}
}
return (ConfigurableApplicationContext) BeanUtils.instantiateClass(contextClass);
}
9. Prepare exception reporter
exceptionReporters = getSpringFactoriesInstances(SpringBootExceptionReporter.class,
new Class[] {
ConfigurableApplicationContext.class }, context);
private <T> Collection<T> getSpringFactoriesInstances(Class<T> type, Class<?>[] parameterTypes, Object... args) {
ClassLoader classLoader = getClassLoader();
// Use names and ensure unique to protect against duplicates
Set<String> names = new LinkedHashSet<>(SpringFactoriesLoader.loadFactoryNames(type, classLoader));
List<T> instances = createSpringFactoriesInstances(type, parameterTypes, classLoader, args, names);
AnnotationAwareOrderComparator.sort(instances);
return instances;
}
10. Prepare the application context
prepareContext(context, environment, listeners, applicationArguments, printedBanner);
private void prepareContext(ConfigurableApplicationContext context, ConfigurableEnvironment environment,
SpringApplicationRunListeners listeners, ApplicationArguments applicationArguments, Banner printedBanner) {
//应用上下文的environment
context.setEnvironment(environment);
//应用上下文后处理
postProcessApplicationContext(context);
//为上下文应用所有初始化器，执行容器中的applicationContextInitializer(spring.factories的实例)，将所有的初始化对象放置到context对象中
applyInitializers(context);
//触发所有SpringApplicationRunListener监听器的ContextPrepared事件方法。添加所有的事件监听器
listeners.contextPrepared(context);
//记录启动日志
if (this.logStartupInfo) {
logStartupInfo(context.getParent() == null);
logStartupProfileInfo(context);
}
// 注册启动参数bean，将容器指定的参数封装成bean，注入容器
ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
beanFactory.registerSingleton("springApplicationArguments", applicationArguments);
//设置banner
if (printedBanner != null) {
beanFactory.registerSingleton("springBootBanner", printedBanner);
}
if (beanFactory instanceof DefaultListableBeanFactory) {
((DefaultListableBeanFactory) beanFactory)
.setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);
}
if (this.lazyInitialization) {
context.addBeanFactoryPostProcessor(new LazyInitializationBeanFactoryPostProcessor());
}
// 加载所有资源，指的是启动器指定的参数
Set<Object> sources = getAllSources();
Assert.notEmpty(sources, "Sources must not be empty");
//将bean加载到上下文中
load(context, sources.toArray(new Object[0]));
//触发所有springapplicationRunListener监听器的contextLoaded事件方法，
listeners.contextLoaded(context);
}
-------------------
//这里没有做任何的处理过程，因为beanNameGenerator和resourceLoader默认为空，可以方便后续做扩展处理
protected void postProcessApplicationContext(ConfigurableApplicationContext context) {
if (this.beanNameGenerator != null) {
context.getBeanFactory().registerSingleton(AnnotationConfigUtils.CONFIGURATION_BEAN_NAME_GENERATOR,
this.beanNameGenerator);
}
if (this.resourceLoader != null) {
if (context instanceof GenericApplicationContext) {
((GenericApplicationContext) context).setResourceLoader(this.resourceLoader);
}
if (context instanceof DefaultResourceLoader) {
((DefaultResourceLoader) context).setClassLoader(this.resourceLoader.getClassLoader());
}
}
if (this.addConversionService) {
context.getBeanFactory().setConversionService(ApplicationConversionService.getSharedInstance());
}
}
---------------------
//将启动器类加载到spring容器中，为后续的自动化配置奠定基础，之前看到的很多注解也与此相关
protected void load(ApplicationContext context, Object[] sources) {
if (logger.isDebugEnabled()) {
logger.debug("Loading source " + StringUtils.arrayToCommaDelimitedString(sources));
}
BeanDefinitionLoader loader = createBeanDefinitionLoader(getBeanDefinitionRegistry(context), sources);
if (this.beanNameGenerator != null) {
loader.setBeanNameGenerator(this.beanNameGenerator);
}
if (this.resourceLoader != null) {
loader.setResourceLoader(this.resourceLoader);
}
if (this.environment != null) {
loader.setEnvironment(this.environment);
}
loader.load();
}
---------------------
//springboot会优先选择groovy加载方式，找不到在选择java方式
private int load(Class<?> source) {
if (isGroovyPresent() && GroovyBeanDefinitionSource.class.isAssignableFrom(source)) {
// Any GroovyLoaders added in beans{} DSL can contribute beans here
GroovyBeanDefinitionSource loader = BeanUtils.instantiateClass(source, GroovyBeanDefinitionSource.class);
load(loader);
}
if (isComponent(source)) {
this.annotatedReader.register(source);
return 1;
}
return 0;
}
11. Refresh the application context
refreshContext(context);
private void refreshContext(ConfigurableApplicationContext context) {
refresh(context);
if (this.registerShutdownHook) {
try {
context.registerShutdownHook();
}
catch (AccessControlException ex) {
// Not allowed in some environments.
}
}
}
------------
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
// Prepare this context for refreshing.
//刷新上下文环境，初始化上下文环境，对系统的环境变量或者系统属性进行准备和校验
prepareRefresh();
// Tell the subclass to refresh the internal bean factory.
//初始化beanfactory，解析xml，相当于之前的xmlBeanfactory操作
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// Prepare the bean factory for use in this context.
//为上下文准备beanfactory，对beanFactory的各种功能进行填充，如@autowired，设置spel表达式解析器，设置编辑注册器，添加applicationContextAwareprocessor处理器等等
prepareBeanFactory(beanFactory);
try {
// Allows post-processing of the bean factory in context subclasses.
//提供子类覆盖的额外处理，即子类处理自定义的beanfactorypostProcess
postProcessBeanFactory(beanFactory);
// Invoke factory processors registered as beans in the context.
//激活各种beanfactory处理器
invokeBeanFactoryPostProcessors(beanFactory);
// Register bean processors that intercept bean creation.
//注册拦截bean创建的bean处理器，即注册beanPostProcessor
registerBeanPostProcessors(beanFactory);
// Initialize message source for this context.
//初始化上下文中的资源文件如国际化文件的处理
initMessageSource();
// Initialize event multicaster for this context.
//初始化上下文事件广播器
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
//给子类扩展初始化其他bean
onRefresh();
// Check for listener beans and register them.
//在所有的bean中查找listener bean,然后 注册到广播器中
registerListeners();
// Instantiate all remaining (non-lazy-init) singletons.
//初始化剩余的非懒惰的bean，即初始化非延迟加载的bean
finishBeanFactoryInitialization(beanFactory);
// Last step: publish corresponding event.
//发完成刷新过程，通知声明周期处理器刷新过程，同时发出ContextRefreshEvent通知别人
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();
}
}
}
12. Application context refresh post-processing
afterRefresh(context, applicationArguments);
//当前方法的代码是空的，可以做一些自定义的后置处理操作
protected void afterRefresh(ConfigurableApplicationContext context, ApplicationArguments args) {
}
13. Stop timing monitoring class: stop the timing listener, and count some task execution information
stopWatch.stop();
public void stop() throws IllegalStateException {
if (this.currentTaskName == null) {
throw new IllegalStateException("Can't stop StopWatch: it's not running");
}
long lastTime = System.nanoTime() - this.startTimeNanos;
this.totalTimeNanos += lastTime;
this.lastTaskInfo = new TaskInfo(this.currentTaskName, lastTime);
if (this.keepTaskList) {
this.taskList.add(this.lastTaskInfo);
}
++this.taskCount;
this.currentTaskName = null;
}
14. Output log records to execute the main class name and time information
if (this.logStartupInfo) {
new StartupInfoLogger(this.mainApplicationClass).logStarted(getApplicationLog(), stopWatch);
}
15. Publish the application context startup completion event: trigger the started event method of all SpringapplicationRunListener listeners
listeners.started(context);
void started(ConfigurableApplicationContext context) {
for (SpringApplicationRunListener listener : this.listeners) {
listener.started(context);
}
}
16. Execute all Runner executors: execute all applicationRunner and CommandLineRunner runners
callRunners(context, applicationArguments);
private void callRunners(ApplicationContext context, ApplicationArguments args) {
List<Object> runners = new ArrayList<>();
runners.addAll(context.getBeansOfType(ApplicationRunner.class).values());
runners.addAll(context.getBeansOfType(CommandLineRunner.class).values());
AnnotationAwareOrderComparator.sort(runners);
for (Object runner : new LinkedHashSet<>(runners)) {
if (runner instanceof ApplicationRunner) {
callRunner((ApplicationRunner) runner, args);
}
if (runner instanceof CommandLineRunner) {
callRunner((CommandLineRunner) runner, args);
}
}
}
17. Publish the application context ready event: trigger the running event method that all springapplicationRunnListener will raise
listeners.running(context);
void running(ConfigurableApplicationContext context) {
for (SpringApplicationRunListener listener : this.listeners) {
listener.running(context);
}
}
18. Return to the application context
return context;
Notice:
The way to obtain the factorys file in the entire springboot framework is unified as follows:
private <T> Collection<T> getSpringFactoriesInstances(Class<T> type) {
return getSpringFactoriesInstances(type, new Class<?>[] {
});
}
-------------------------------------
private <T> Collection<T> getSpringFactoriesInstances(Class<T> type, Class<?>[] parameterTypes, Object... args) {
ClassLoader classLoader = getClassLoader();
// Use names and ensure unique to protect against duplicates
Set<String> names = new LinkedHashSet<>(SpringFactoriesLoader.loadFactoryNames(type, classLoader));
List<T> instances = createSpringFactoriesInstances(type, parameterTypes, classLoader, args, names);
AnnotationAwareOrderComparator.sort(instances);
return instances;
}
-----------------------------
public static List<String> loadFactoryNames(Class<?> factoryType, @Nullable ClassLoader classLoader) {
String factoryTypeName = factoryType.getName();
return loadSpringFactories(classLoader).getOrDefault(factoryTypeName, Collections.emptyList());
}
private static Map<String, List<String>> loadSpringFactories(@Nullable ClassLoader classLoader) {
MultiValueMap<String, String> result = cache.get(classLoader);
if (result != null) {
return result;
}
try {
Enumeration<URL> urls = (classLoader != null ?
classLoader.getResources(FACTORIES_RESOURCE_LOCATION) :
ClassLoader.getSystemResources(FACTORIES_RESOURCE_LOCATION));
result = new LinkedMultiValueMap<>();
while (urls.hasMoreElements()) {
URL url = urls.nextElement();
UrlResource resource = new UrlResource(url);
Properties properties = PropertiesLoaderUtils.loadProperties(resource);
for (Map.Entry<?, ?> entry : properties.entrySet()) {
String factoryTypeName = ((String) entry.getKey()).trim();
for (String factoryImplementationName : StringUtils.commaDelimitedListToStringArray((String) entry.getValue())) {
result.add(factoryTypeName, factoryImplementationName.trim());
}
}
}
cache.put(classLoader, result);
return result;
}
catch (IOException ex) {
throw new IllegalArgumentException("Unable to load factories from location [" +
FACTORIES_RESOURCE_LOCATION + "]", ex);
}
}
-------------------------
private <T> List<T> createSpringFactoriesInstances(Class<T> type, Class<?>[] parameterTypes,
ClassLoader classLoader, Object[] args, Set<String> names) {
List<T> instances = new ArrayList<>(names.size());
for (String name : names) {
try {
//装载class文件到内存
Class<?> instanceClass = ClassUtils.forName(name, classLoader);
Assert.isAssignable(type, instanceClass);
Constructor<?> constructor = instanceClass.getDeclaredConstructor(parameterTypes);
//通过反射创建实例
T instance = (T) BeanUtils.instantiateClass(constructor, args);
instances.add(instance);
}
catch (Throwable ex) {
throw new IllegalArgumentException("Cannot instantiate " + type + " : " + name, ex);
}
}
return instances;
}
The role of the classes in the spring.factory file:
# PropertySource Loaders 属性文件加载器
org.springframework.boot.env.PropertySourceLoader=\
# properties文件加载器
org.springframework.boot.env.PropertiesPropertySourceLoader,\
# yaml文件加载器
org.springframework.boot.env.YamlPropertySourceLoader
# Run Listeners 运行时的监听器
org.springframework.boot.SpringApplicationRunListener=\
# 程序运行过程中所有监听通知都是通过此类来进行回调
org.springframework.boot.context.event.EventPublishingRunListener
# Error Reporters 错误报告器
org.springframework.boot.SpringBootExceptionReporter=\
org.springframework.boot.diagnostics.FailureAnalyzers
# Application Context Initializers
org.springframework.context.ApplicationContextInitializer=\
# 报告spring容器的一些常见的错误配置
org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer,\
# 设置spring应用上下文的ID
org.springframework.boot.context.ContextIdApplicationContextInitializer,\
# 使用环境属性context.initializer.classes指定初始化器进行初始化规则
org.springframework.boot.context.config.DelegatingApplicationContextInitializer,\
org.springframework.boot.rsocket.context.RSocketPortInfoApplicationContextInitializer,\
# 将内置servlet容器实际使用的监听端口写入到environment环境属性中
org.springframework.boot.web.context.ServerPortInfoApplicationContextInitializer
# Application Listeners
org.springframework.context.ApplicationListener=\
# 应用上下文加载完成后对缓存做清除工作，响应事件ContextRefreshEvent
org.springframework.boot.ClearCachesApplicationListener,\
# 监听双亲应用上下文的关闭事件并往自己的孩子应用上下文中传播，相关事件ParentContextAvailableEvent/ContextClosedEvent
org.springframework.boot.builder.ParentContextCloserApplicationListener,\
org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor,\
# 如果系统文件编码和环境变量中指定的不同则终止应用启动。具体的方法是比较系统属性file.encoding和环境变量spring.mandatory-file-encoding是否相等(大小写不敏感)。
org.springframework.boot.context.FileEncodingApplicationListener,\
# 根据spring.output.ansi.enabled参数配置AnsiOutput
org.springframework.boot.context.config.AnsiOutputApplicationListener,\
# EnvironmentPostProcessor，从常见的那些约定的位置读取配置文件，比如从以下目录读取#application.properties,application.yml等配置文件：
# classpath:
# file:.
# classpath:config
# file:./config/:
# 也可以配置成从其他指定的位置读取配置文件
org.springframework.boot.context.config.ConfigFileApplicationListener,\
# 监听到事件后转发给环境变量context.listener.classes指定的那些事件监听器
org.springframework.boot.context.config.DelegatingApplicationListener,\
# 一个SmartApplicationListener,对环境就绪事件ApplicationEnvironmentPreparedEvent/应用失败事件ApplicationFailedEvent做出响应，往日志DEBUG级别输出TCCL(thread context class loader)的classpath。
org.springframework.boot.context.logging.ClasspathLoggingApplicationListener,\
# 检测正在使用的日志系统，默认时logback，，此时日志系统还没有初始化
org.springframework.boot.context.logging.LoggingApplicationListener,\
# 使用一个可以和Spring Boot可执行jar包配合工作的版本替换liquibase ServiceLocator
org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener
# Environment Post Processors
org.springframework.boot.env.EnvironmentPostProcessor=\
org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor,\
org.springframework.boot.env.SpringApplicationJsonEnvironmentPostProcessor,\
org.springframework.boot.env.SystemEnvironmentPropertySourceEnvironmentPostProcessor,\
org.springframework.boot.reactor.DebugAgentEnvironmentPostProcessor
# Failure Analyzers
org.springframework.boot.diagnostics.FailureAnalyzer=\
org.springframework.boot.diagnostics.analyzer.BeanCurrentlyInCreationFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.BeanDefinitionOverrideFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.BeanNotOfRequiredTypeFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.BindFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.BindValidationFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.UnboundConfigurationPropertyFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.ConnectorStartFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.NoSuchMethodFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.NoUniqueBeanDefinitionFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.PortInUseFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.ValidationExceptionFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.InvalidConfigurationPropertyNameFailureAnalyzer,\
org.springframework.boot.diagnostics.analyzer.InvalidConfigurationPropertyValueFailureAnalyzer
# FailureAnalysisReporters
org.springframework.boot.diagnostics.FailureAnalysisReporter=\
org.springframework.boot.diagnostics.LoggingFailureAnalysisReporter
# Initializers
org.springframework.context.ApplicationContextInitializer=\
org.springframework.boot.autoconfigure.SharedMetadataReaderFactoryContextInitializer,\
org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListener
# Application Listeners
org.springframework.context.ApplicationListener=\
# 另外单独启动一个线程实例化并调用run方法，包括验证器、消息转换器等
org.springframework.boot.autoconfigure.BackgroundPreinitializer
# Auto Configuration Import Listeners
org.springframework.boot.autoconfigure.AutoConfigurationImportListener=\
org.springframework.boot.autoconfigure.condition.ConditionEvaluationReportAutoConfigurationImportListener
# Auto Configuration Import Filters
org.springframework.boot.autoconfigure.AutoConfigurationImportFilter=\
org.springframework.boot.autoconfigure.condition.OnBeanCondition,\
org.springframework.boot.autoconfigure.condition.OnClassCondition,\
org.springframework.boot.autoconfigure.condition.OnWebApplicationCondition
# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\
org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration,\
org.springframework.boot.autoconfigure.batch.BatchAutoConfiguration,\
org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration,\
org.springframework.boot.autoconfigure.cassandra.CassandraAutoConfiguration,\
org.springframework.boot.autoconfigure.cloud.CloudServiceConnectorsAutoConfiguration,\
org.springframework.boot.autoconfigure.context.ConfigurationPropertiesAutoConfiguration,\
org.springframework.boot.autoconfigure.context.MessageSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.context.PropertyPlaceholderAutoConfiguration,\
org.springframework.boot.autoconfigure.couchbase.CouchbaseAutoConfiguration,\
org.springframework.boot.autoconfigure.dao.PersistenceExceptionTranslationAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.cassandra.CassandraRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.couchbase.CouchbaseRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveElasticsearchRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.elasticsearch.ReactiveRestClientAutoConfiguration,\
org.springframework.boot.autoconfigure.data.jdbc.JdbcRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.jpa.JpaRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.ldap.LdapRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoReactiveRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.mongo.MongoRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jDataAutoConfiguration,\
org.springframework.boot.autoconfigure.data.neo4j.Neo4jRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.solr.SolrRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.data.redis.RedisRepositoriesAutoConfiguration,\
org.springframework.boot.autoconfigure.data.rest.RepositoryRestMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.data.web.SpringDataWebAutoConfiguration,\
org.springframework.boot.autoconfigure.elasticsearch.jest.JestAutoConfiguration,\
org.springframework.boot.autoconfigure.elasticsearch.rest.RestClientAutoConfiguration,\
org.springframework.boot.autoconfigure.flyway.FlywayAutoConfiguration,\
org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration,\
org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration,\
org.springframework.boot.autoconfigure.h2.H2ConsoleAutoConfiguration,\
org.springframework.boot.autoconfigure.hateoas.HypermediaAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastAutoConfiguration,\
org.springframework.boot.autoconfigure.hazelcast.HazelcastJpaDependencyAutoConfiguration,\
org.springframework.boot.autoconfigure.http.HttpMessageConvertersAutoConfiguration,\
org.springframework.boot.autoconfigure.http.codec.CodecsAutoConfiguration,\
org.springframework.boot.autoconfigure.influx.InfluxDbAutoConfiguration,\
org.springframework.boot.autoconfigure.info.ProjectInfoAutoConfiguration,\
org.springframework.boot.autoconfigure.integration.IntegrationAutoConfiguration,\
org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.JndiDataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.XADataSourceAutoConfiguration,\
org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JmsAutoConfiguration,\
org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.JndiConnectionFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.activemq.ActiveMQAutoConfiguration,\
org.springframework.boot.autoconfigure.jms.artemis.ArtemisAutoConfiguration,\
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.jersey.JerseyAutoConfiguration,\
org.springframework.boot.autoconfigure.jooq.JooqAutoConfiguration,\
org.springframework.boot.autoconfigure.jsonb.JsonbAutoConfiguration,\
org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration,\
org.springframework.boot.autoconfigure.ldap.embedded.EmbeddedLdapAutoConfiguration,\
org.springframework.boot.autoconfigure.ldap.LdapAutoConfiguration,\
org.springframework.boot.autoconfigure.liquibase.LiquibaseAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderAutoConfiguration,\
org.springframework.boot.autoconfigure.mail.MailSenderValidatorAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.embedded.EmbeddedMongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration,\
org.springframework.boot.autoconfigure.mongo.MongoReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.mustache.MustacheAutoConfiguration,\
org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration,\
org.springframework.boot.autoconfigure.quartz.QuartzAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketMessagingAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketRequesterAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketServerAutoConfiguration,\
org.springframework.boot.autoconfigure.rsocket.RSocketStrategiesAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.UserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.security.servlet.SecurityFilterAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.reactive.ReactiveUserDetailsServiceAutoConfiguration,\
org.springframework.boot.autoconfigure.security.rsocket.RSocketSecurityAutoConfiguration,\
org.springframework.boot.autoconfigure.security.saml2.Saml2RelyingPartyAutoConfiguration,\
org.springframework.boot.autoconfigure.sendgrid.SendGridAutoConfiguration,\
org.springframework.boot.autoconfigure.session.SessionAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.client.servlet.OAuth2ClientAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.client.reactive.ReactiveOAuth2ClientAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.resource.servlet.OAuth2ResourceServerAutoConfiguration,\
org.springframework.boot.autoconfigure.security.oauth2.resource.reactive.ReactiveOAuth2ResourceServerAutoConfiguration,\
org.springframework.boot.autoconfigure.solr.SolrAutoConfiguration,\
org.springframework.boot.autoconfigure.task.TaskExecutionAutoConfiguration,\
org.springframework.boot.autoconfigure.task.TaskSchedulingAutoConfiguration,\
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.TransactionAutoConfiguration,\
org.springframework.boot.autoconfigure.transaction.jta.JtaAutoConfiguration,\
org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration,\
org.springframework.boot.autoconfigure.web.client.RestTemplateAutoConfiguration,\
org.springframework.boot.autoconfigure.web.embedded.EmbeddedWebServerFactoryCustomizerAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.HttpHandlerAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.ReactiveWebServerFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.WebFluxAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.error.ErrorWebFluxAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.function.client.ClientHttpConnectorAutoConfiguration,\
org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.DispatcherServletAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.error.ErrorMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.HttpEncodingAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration,\
org.springframework.boot.autoconfigure.web.servlet.WebMvcAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.reactive.WebSocketReactiveAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketServletAutoConfiguration,\
org.springframework.boot.autoconfigure.websocket.servlet.WebSocketMessagingAutoConfiguration,\
org.springframework.boot.autoconfigure.webservices.WebServicesAutoConfiguration,\
org.springframework.boot.autoconfigure.webservices.client.WebServiceTemplateAutoConfiguration
# Failure analyzers
org.springframework.boot.diagnostics.FailureAnalyzer=\
org.springframework.boot.autoconfigure.diagnostics.analyzer.NoSuchBeanDefinitionFailureAnalyzer,\
org.springframework.boot.autoconfigure.flyway.FlywayMigrationScriptMissingFailureAnalyzer,\
org.springframework.boot.autoconfigure.jdbc.DataSourceBeanCreationFailureAnalyzer,\
org.springframework.boot.autoconfigure.jdbc.HikariDriverConfigurationFailureAnalyzer,\
org.springframework.boot.autoconfigure.session.NonUniqueSessionRepositoryFailureAnalyzer
# Template availability providers
org.springframework.boot.autoconfigure.template.TemplateAvailabilityProvider=\
org.springframework.boot.autoconfigure.freemarker.FreeMarkerTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.mustache.MustacheTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.groovy.template.GroovyTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.thymeleaf.ThymeleafTemplateAvailabilityProvider,\
org.springframework.boot.autoconfigure.web.servlet.JspTemplateAvailabilityProvider