SpringBoot 源码解析 （二）----- Spring Boot精髓：启动流程源码分析

@SpringBootApplication
public class HelloWorldMainApplication { public static void main(String[] args) {
SpringApplication.run(HelloWorldMainApplication.class, args);
}}

// 调用静态类，参数对应的就是HelloWorldMainApplication.class以及main方法中的args
public static ConfigurableApplicationContext run(Class<?> primarySource,String... args) {
return run(new Class<?>[] { primarySource }, args);
}
public static ConfigurableApplicationContext run(Object[] sources, String[] args) {
return (new SpringApplication(sources)).run(args);
}

public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) {
this.resourceLoader = resourceLoader;
Assert.notNull(primarySources, "PrimarySources must not be null");
//把HelloWorldMainApplication.class设置为属性存储起来
this.primarySources = new LinkedHashSet<>(Arrays.asList(primarySources));
//设置应用类型是Standard还是Web
this.webApplicationType = deduceWebApplicationType();
//设置初始化器(Initializer),最后会调用这些初始化器
setInitializers((Collection) getSpringFactoriesInstances( ApplicationContextInitializer.class));
//设置监听器(Listener)
setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
this.mainApplicationClass = deduceMainApplicationClass();
}

private WebApplicationType deduceWebApplicationType() {
if (ClassUtils.isPresent(REACTIVE_WEB_ENVIRONMENT_CLASS, null)
&& !ClassUtils.isPresent(MVC_WEB_ENVIRONMENT_CLASS, null)) {
return WebApplicationType.REACTIVE;
}
for (String className : WEB_ENVIRONMENT_CLASSES) {
if (!ClassUtils.isPresent(className, null)) {
return WebApplicationType.NONE;
}
}
return WebApplicationType.SERVLET;
}// 相关常量
private static final String REACTIVE_WEB_ENVIRONMENT_CLASS = "org.springframework."
+ "web.reactive.DispatcherHandler";
private static final String MVC_WEB_ENVIRONMENT_CLASS = "org.springframework."
+ "web.servlet.DispatcherServlet";
private static final String[] WEB_ENVIRONMENT_CLASSES = { "javax.servlet.Servlet",
"org.springframework.web.context.ConfigurableWebApplicationContext" };

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>5.0.5.RELEASE</version>
<scope>compile</scope>
</dependency>

public enum WebApplicationType {
NONE,
SERVLET,
REACTIVE; private WebApplicationType() {
}
}

//设置初始化器(Initializer),最后会调用这些初始化器
setInitializers((Collection) getSpringFactoriesInstances( ApplicationContextInitializer.class));

private <T> Collection<T> getSpringFactoriesInstances(Class<T> type) {
return getSpringFactoriesInstances(type, new Class<?>[] {});
}// 这里的入参type就是ApplicationContextInitializer.class
private <T> Collection<T> getSpringFactoriesInstances(Class<T> type,
Class<?>[] parameterTypes, Object... args) {
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
// 使用Set保存names来避免重复元素
Set<String> names = new LinkedHashSet<>(
SpringFactoriesLoader.loadFactoryNames(type, classLoader));
// 根据names来进行实例化
List<T> instances = createSpringFactoriesInstances(type, parameterTypes,
classLoader, args, names);
// 对实例进行排序
AnnotationAwareOrderComparator.sort(instances);
return instances;
}

// 入参就是ApplicationContextInitializer.class
public static List<String> loadFactoryNames(Class<?> factoryClass, ClassLoader classLoader) {
String factoryClassName = factoryClass.getName(); try {
//从类路径的META-INF/spring.factories中加载所有默认的自动配置类
Enumeration<URL> urls = classLoader != null?classLoader.getResources("META-INF/spring.factories"):ClassLoader.getSystemResources("META-INF/spring.factories");
ArrayList result = new ArrayList(); while(urls.hasMoreElements()) {
URL url = (URL)urls.nextElement();
Properties properties = PropertiesLoaderUtils.loadProperties(new UrlResource(url));
//获取ApplicationContextInitializer.class的所有值
String factoryClassNames = properties.getProperty(factoryClassName);
result.addAll(Arrays.asList(StringUtils.commaDelimitedListToStringArray(factoryClassNames)));
} return result;
} catch (IOException var8) {
throw new IllegalArgumentException("Unable to load [" + factoryClass.getName() + "] factories from location [" + "META-INF/spring.factories" + "]", var8);
}
}

org.springframework.context.ApplicationContextInitializer=\
org.springframework.boot.autoconfigure.SharedMetadataReaderFactoryContextInitializer,\
org.springframework.boot.autoconfigure.logging.AutoConfigurationReportLoggingInitializer

// parameterTypes: 上一步得到的names集合
private <T> List<T> createSpringFactoriesInstances(Class<T> type,
Class<?>[] parameterTypes, ClassLoader classLoader, Object[] args,
Set<String> names) {
List<T> instances = new ArrayList<T>(names.size());
for (String name : names) {
try {
Class<?> instanceClass = ClassUtils.forName(name, classLoader);
//确认被加载类是ApplicationContextInitializer的子类
Assert.isAssignable(type, instanceClass);
Constructor<?> constructor = instanceClass.getDeclaredConstructor(parameterTypes);
//反射实例化对象
T instance = (T) BeanUtils.instantiateClass(constructor, args);
//加入List集合中
instances.add(instance);
}
catch (Throwable ex) {
throw new IllegalArgumentException(
"Cannot instantiate " + type + " : " + name, ex);
}
}
return instances;
}

public interface ApplicationContextInitializer<C extends ConfigurableApplicationContext> { void initialize(C applicationContext);}

setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));

// 这里的入参type是：org.springframework.context.ApplicationListener.class
private <T> Collection<? extends T> getSpringFactoriesInstances(Class<T> type) {
return getSpringFactoriesInstances(type, new Class<?>[] {});
}private <T> Collection<? extends T> getSpringFactoriesInstances(Class<T> type,
Class<?>[] parameterTypes, Object... args) {
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
// Use names and ensure unique to protect against duplicates
Set<String> names = new LinkedHashSet<String>(
SpringFactoriesLoader.loadFactoryNames(type, classLoader));
List<T> instances = createSpringFactoriesInstances(type, parameterTypes,
classLoader, args, names);
AnnotationAwareOrderComparator.sort(instances);
return instances;
}

org.springframework.context.ApplicationListener=\
org.springframework.boot.autoconfigure.BackgroundPreinitializerorg.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

public ConfigurableApplicationContext run(String... args) {
// 计时工具
StopWatch stopWatch = new StopWatch();
stopWatch.start(); ConfigurableApplicationContext context = null;
Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>(); configureHeadlessProperty(); // 第一步：获取并启动监听器
SpringApplicationRunListeners listeners = getRunListeners(args);
listeners.starting(); try {
ApplicationArguments applicationArguments = new DefaultApplicationArguments(args); // 第二步：根据SpringApplicationRunListeners以及参数来准备环境
ConfigurableEnvironment environment = prepareEnvironment(listeners,applicationArguments);
configureIgnoreBeanInfo(environment); // 准备Banner打印器 - 就是启动Spring Boot的时候打印在console上的ASCII艺术字体
Banner printedBanner = printBanner(environment); // 第三步：创建Spring容器
context = createApplicationContext(); exceptionReporters = getSpringFactoriesInstances(
SpringBootExceptionReporter.class,
new Class[] { ConfigurableApplicationContext.class }, context); // 第四步：Spring容器前置处理
prepareContext(context, environment, listeners, applicationArguments,printedBanner); // 第五步：刷新容器
refreshContext(context);
// 第六步：Spring容器后置处理
afterRefresh(context, applicationArguments); // 第七步：发出结束执行的事件
listeners.started(context);
// 第八步：执行Runners
this.callRunners(context, applicationArguments);
stopWatch.stop();
// 返回容器
return context;
}
catch (Throwable ex) {
handleRunFailure(context, listeners, exceptionReporters, ex);
throw new IllegalStateException(ex);
}
}

private SpringApplicationRunListeners getRunListeners(String[] args) {
Class<?>[] types = new Class<?>[] { SpringApplication.class, String[].class };
return new SpringApplicationRunListeners(logger, getSpringFactoriesInstances(SpringApplicationRunListener.class, types, this, args));
}

org.springframework.boot.SpringApplicationRunListener=\
org.springframework.boot.context.event.EventPublishingRunListener

public class EventPublishingRunListener implements SpringApplicationRunListener, Ordered {
private final SpringApplication application;
private final String[] args;
//广播器
private final SimpleApplicationEventMulticaster initialMulticaster;

public EventPublishingRunListener(SpringApplication application, String[] args) {
this.application = application;
this.args = args;
this.initialMulticaster = new SimpleApplicationEventMulticaster();
Iterator var3 = application.getListeners().iterator();

while(var3.hasNext()) {
ApplicationListener<?> listener = (ApplicationListener)var3.next();
//将上面设置到SpringApplication的十一个监听器全部添加到SimpleApplicationEventMulticaster这个广播器中
this.initialMulticaster.addApplicationListener(listener);
} }
//略...
}

public abstract class AbstractApplicationEventMulticaster implements ApplicationEventMulticaster, BeanClassLoaderAware, BeanFactoryAware {
//广播器的父类中存放保存监听器的内部内
private final AbstractApplicationEventMulticaster.ListenerRetriever defaultRetriever = new AbstractApplicationEventMulticaster.ListenerRetriever(false); @Override
public void addApplicationListener(ApplicationListener<?> listener) {
synchronized (this.retrievalMutex) {
Object singletonTarget = AopProxyUtils.getSingletonTarget(listener);
if (singletonTarget instanceof ApplicationListener) {
this.defaultRetriever.applicationListeners.remove(singletonTarget);
}
//内部类对象
this.defaultRetriever.applicationListeners.add(listener);
this.retrieverCache.clear();
}
} private class ListenerRetriever {
//保存所有的监听器
public final Set<ApplicationListener<?>> applicationListeners = new LinkedHashSet();
public final Set<String> applicationListenerBeans = new LinkedHashSet();
private final boolean preFiltered; public ListenerRetriever(boolean preFiltered) {
this.preFiltered = preFiltered;
} public Collection<ApplicationListener<?>> getApplicationListeners() {
LinkedList<ApplicationListener<?>> allListeners = new LinkedList();
Iterator var2 = this.applicationListeners.iterator(); while(var2.hasNext()) {
ApplicationListener<?> listener = (ApplicationListener)var2.next();
allListeners.add(listener);
} if (!this.applicationListenerBeans.isEmpty()) {
BeanFactory beanFactory = AbstractApplicationEventMulticaster.this.getBeanFactory();
Iterator var8 = this.applicationListenerBeans.iterator(); while(var8.hasNext()) {
String listenerBeanName = (String)var8.next(); try {
ApplicationListener<?> listenerx = (ApplicationListener)beanFactory.getBean(listenerBeanName, ApplicationListener.class);
if (this.preFiltered || !allListeners.contains(listenerx)) {
allListeners.add(listenerx);
}
} catch (NoSuchBeanDefinitionException var6) {
;
}
}
} AnnotationAwareOrderComparator.sort(allListeners);
return allListeners;
}
}
//略...
}

public class EventPublishingRunListener implements SpringApplicationRunListener, Ordered {
private final SpringApplication application;
private final String[] args;
private final SimpleApplicationEventMulticaster initialMulticaster;

package org.springframework.boot;
public interface SpringApplicationRunListener { // 在run()方法开始执行时，该方法就立即被调用，可用于在初始化最早期时做一些工作
void starting();
// 当environment构建完成，ApplicationContext创建之前，该方法被调用
void environmentPrepared(ConfigurableEnvironment environment);
// 当ApplicationContext构建完成时，该方法被调用
void contextPrepared(ConfigurableApplicationContext context);
// 在ApplicationContext完成加载，但没有被刷新前，该方法被调用
void contextLoaded(ConfigurableApplicationContext context);
// 在ApplicationContext刷新并启动后，CommandLineRunners和ApplicationRunner未被调用前，该方法被调用
void started(ConfigurableApplicationContext context);
// 在run()方法执行完成前该方法被调用
void running(ConfigurableApplicationContext context);
// 当应用运行出错时该方法被调用
void failed(ConfigurableApplicationContext context, Throwable exception);
}

@Override
public void starting() {
//关键代码，先创建application启动事件`ApplicationStartingEvent`
this.initialMulticaster.multicastEvent(new ApplicationStartingEvent(this.application, this.args));
}

@Override
public void multicastEvent(final ApplicationEvent event, @Nullable ResolvableType eventType) {
ResolvableType type = (eventType != null ? eventType : resolveDefaultEventType(event));
//通过事件类型ApplicationStartingEvent获取对应的监听器
for (final ApplicationListener<?> listener : getApplicationListeners(event, type)) {
//获取线程池，如果为空则同步处理。这里线程池为空，还未没初始化。
Executor executor = getTaskExecutor();
if (executor != null) {
//异步发送事件
executor.execute(() -> invokeListener(listener, event));
}
else {
//同步发送事件
invokeListener(listener, event);
}
}
}

@Override
public void onApplicationEvent(ApplicationEvent event) {
//在springboot启动的时候
if (event instanceof ApplicationStartedEvent) {
onApplicationStartedEvent((ApplicationStartedEvent) event);
}
//springboot的Environment环境准备完成的时候
else if (event instanceof ApplicationEnvironmentPreparedEvent) {
onApplicationEnvironmentPreparedEvent(
(ApplicationEnvironmentPreparedEvent) event);
}
//在springboot容器的环境设置完成以后
else if (event instanceof ApplicationPreparedEvent) {
onApplicationPreparedEvent((ApplicationPreparedEvent) event);
}
//容器关闭的时候
else if (event instanceof ContextClosedEvent && ((ContextClosedEvent) event)
.getApplicationContext().getParent() == null) {
onContextClosedEvent();
}
//容器启动失败的时候
else if (event instanceof ApplicationFailedEvent) {
onApplicationFailedEvent();
}
}

ConfigurableEnvironment environment = prepareEnvironment(listeners,applicationArguments);

private ConfigurableEnvironment prepareEnvironment(
SpringApplicationRunListeners listeners,
ApplicationArguments applicationArguments) {
//获取对应的ConfigurableEnvironment
ConfigurableEnvironment environment = getOrCreateEnvironment();
//配置
configureEnvironment(environment, applicationArguments.getSourceArgs());
//发布环境已准备事件，这是第二次发布事件
listeners.environmentPrepared(environment);
bindToSpringApplication(environment);
ConfigurationPropertySources.attach(environment);
return environment;
}

private ConfigurableEnvironment getOrCreateEnvironment() {
if (this.environment != null) {
return this.environment;
}
if (this.webApplicationType == WebApplicationType.SERVLET) {
return new StandardServletEnvironment();
}
return new StandardEnvironment();
}

# Environment Post Processors
org.springframework.boot.env.EnvironmentPostProcessor=
org.springframework.boot.cloud.CloudFoundryVcapEnvironmentPostProcessor，
org.springframework.boot.env.SpringApplicationJsonEnvironmentPostProcessor，
org.springframework.boot.env.SystemEnvironmentPropertySourceEnvironmentPostProcessor

private static final String DEFAULT_SEARCH_LOCATIONS = "classpath:/,classpath:/config/,file:./,file:./config/";

context = createApplicationContext();

public static final String DEFAULT_WEB_CONTEXT_CLASS = "org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext";
protected ConfigurableApplicationContext createApplicationContext() {
Class<?> contextClass = this.applicationContextClass;
if (contextClass == null) {
try {
switch (this.webApplicationType) {
case SERVLET:
contextClass = Class.forName(DEFAULT_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);
}

prepareContext(context, environment, listeners, applicationArguments,printedBanner);

private void prepareContext(ConfigurableApplicationContext context,
ConfigurableEnvironment environment, SpringApplicationRunListeners listeners,
ApplicationArguments applicationArguments, Banner printedBanner) {
//设置容器环境，包括各种变量
context.setEnvironment(environment);
//执行容器后置处理
postProcessApplicationContext(context);
//执行容器中的ApplicationContextInitializer（包括 spring.factories和自定义的实例）
applyInitializers(context);
//发送容器已经准备好的事件，通知各监听器
listeners.contextPrepared(context); //注册启动参数bean，这里将容器指定的参数封装成bean，注入容器
context.getBeanFactory().registerSingleton("springApplicationArguments",
applicationArguments);
//设置banner
if (printedBanner != null) {
context.getBeanFactory().registerSingleton("springBootBanner", printedBanner);
}
//获取我们的启动类指定的参数，可以是多个
Set<Object> sources = getAllSources();
Assert.notEmpty(sources, "Sources must not be empty");
//加载我们的启动类，将启动类注入容器
load(context, sources.toArray(new Object[0]));
//发布容器已加载事件。
listeners.contextLoaded(context);
}

protected void applyInitializers(ConfigurableApplicationContext context) {
// 1. 从SpringApplication类中的initializers集合获取所有的ApplicationContextInitializer
for (ApplicationContextInitializer initializer : getInitializers()) {
// 2. 循环调用ApplicationContextInitializer中的initialize方法
Class<?> requiredType = GenericTypeResolver.resolveTypeArgument(
initializer.getClass(), ApplicationContextInitializer.class);
Assert.isInstanceOf(requiredType, context, "Unable to call initializer.");
initializer.initialize(context);
}
}

public Set<Object> getAllSources() {
Set<Object> allSources = new LinkedHashSet();
if (!CollectionUtils.isEmpty(this.primarySources)) {
//获取primarySources属性，也就是之前存储的HelloWorldMainApplication.class
allSources.addAll(this.primarySources);
} if (!CollectionUtils.isEmpty(this.sources)) {
allSources.addAll(this.sources);
} return Collections.unmodifiableSet(allSources);
}

protected void load(ApplicationContext context, Object[] 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();
}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)) {
//以注解的方式，将启动类bean信息存入beanDefinitionMap，也就是将HelloWorldMainApplication.class存入了beanDefinitionMap
this.annotatedReader.register(source);
return 1;
}
return 0;
}

listeners.contextLoaded(context);

protected void refresh(ApplicationContext applicationContext) {
Assert.isInstanceOf(AbstractApplicationContext.class, applicationContext);
//调用创建的容器applicationContext中的refresh()方法
((AbstractApplicationContext)applicationContext).refresh();
}
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
/**
* 刷新上下文环境
*/
prepareRefresh(); /**
* 初始化BeanFactory，解析XML，相当于之前的XmlBeanFactory的操作，
*/
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); /**
* 为上下文准备BeanFactory，即对BeanFactory的各种功能进行填充，如常用的注解@Autowired @Qualifier等
* 添加ApplicationContextAwareProcessor处理器
* 在依赖注入忽略实现*Aware的接口，如EnvironmentAware、ApplicationEventPublisherAware等
* 注册依赖，如一个bean的属性中含有ApplicationEventPublisher(beanFactory)，则会将beanFactory的实例注入进去
*/
prepareBeanFactory(beanFactory); try {
/**
* 提供子类覆盖的额外处理，即子类处理自定义的BeanFactoryPostProcess
*/
postProcessBeanFactory(beanFactory); /**
* 激活各种BeanFactory处理器,包括BeanDefinitionRegistryBeanFactoryPostProcessor和普通的BeanFactoryPostProcessor
* 执行对应的postProcessBeanDefinitionRegistry方法 和 postProcessBeanFactory方法
*/
invokeBeanFactoryPostProcessors(beanFactory); /**
* 注册拦截Bean创建的Bean处理器，即注册BeanPostProcessor，不是BeanFactoryPostProcessor，注意两者的区别
* 注意，这里仅仅是注册，并不会执行对应的方法，将在bean的实例化时执行对应的方法
*/
registerBeanPostProcessors(beanFactory); /**
* 初始化上下文中的资源文件，如国际化文件的处理等
*/
initMessageSource(); /**
* 初始化上下文事件广播器，并放入applicatioEventMulticaster,如ApplicationEventPublisher
*/
initApplicationEventMulticaster(); /**
* 给子类扩展初始化其他Bean
*/
onRefresh(); /**
* 在所有bean中查找listener bean，然后注册到广播器中
*/
registerListeners(); /**
* 设置转换器
* 注册一个默认的属性值解析器
* 冻结所有的bean定义，说明注册的bean定义将不能被修改或进一步的处理
* 初始化剩余的非惰性的bean，即初始化非延迟加载的bean
*/
finishBeanFactoryInitialization(beanFactory); /**
* 通过spring的事件发布机制发布ContextRefreshedEvent事件，以保证对应的监听器做进一步的处理
* 即对那种在spring启动后需要处理的一些类，这些类实现了ApplicationListener<ContextRefreshedEvent>，
* 这里就是要触发这些类的执行(执行onApplicationEvent方法)
* 另外，spring的内置Event有ContextClosedEvent、ContextRefreshedEvent、ContextStartedEvent、ContextStoppedEvent、RequestHandleEvent
* 完成初始化，通知生命周期处理器lifeCycleProcessor刷新过程，同时发出ContextRefreshEvent通知其他人
*/
finishRefresh();
} finally { resetCommonCaches();
}
}
}

protected void afterRefresh(ConfigurableApplicationContext context,
ApplicationArguments args) {
}

public void started(ConfigurableApplicationContext context) {
//这里就是获取的EventPublishingRunListener
Iterator var2 = this.listeners.iterator(); while(var2.hasNext()) {
SpringApplicationRunListener listener = (SpringApplicationRunListener)var2.next();
//执行EventPublishingRunListener的started方法
listener.started(context);
}
}public void started(ConfigurableApplicationContext context) {
//创建ApplicationStartedEvent事件，并且发布事件
//我们看到是执行的ConfigurableApplicationContext这个容器的publishEvent方法，和前面的starting是不同的
context.publishEvent(new ApplicationStartedEvent(this.application, this.args, context));
}

private void callRunners(ApplicationContext context, ApplicationArguments args) {
List<Object> runners = new ArrayList<Object>();
//获取容器中所有的ApplicationRunner的Bean实例
runners.addAll(context.getBeansOfType(ApplicationRunner.class).values());
//获取容器中所有的CommandLineRunner的Bean实例
runners.addAll(context.getBeansOfType(CommandLineRunner.class).values());
AnnotationAwareOrderComparator.sort(runners);
for (Object runner : new LinkedHashSet<Object>(runners)) {
if (runner instanceof ApplicationRunner) {
//执行ApplicationRunner的run方法
callRunner((ApplicationRunner) runner, args);
}
if (runner instanceof CommandLineRunner) {
//执行CommandLineRunner的run方法
callRunner((CommandLineRunner) runner, args);
}
}
}

private void callRunner(ApplicationRunner runner, ApplicationArguments args) {
try {
runner.run(args);
} catch (Exception var4) {
throw new IllegalStateException("Failed to execute ApplicationRunner", var4);
}
}

private void callRunner(CommandLineRunner runner, ApplicationArguments args) {
try {
runner.run(args.getSourceArgs());
} catch (Exception var4) {
throw new IllegalStateException("Failed to execute CommandLineRunner", var4);
}
}