SpringBoot 源码分析(一) 启动过程分析
SpringBoot源码核心内容
SpringBoot的源码主要核心有以下几块;
1、是run()方法 ，做一些准备工作
2、是自动装配原理
3、配置文件加载原理
4、tomcat内嵌原理
一、springboot.run()方法分析
在run方法中主要做的事情如下：
@SpringBootApplication
public class StartupApplication {
public static void main(String[] args) {
SpringApplication.run(StartupApplication.class, args);
}
}
当程序开始执行之后，会调用SpringApplication的构造方法，进行某些初始参数的设置
//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();
}
在上述构造方法中，有一个判断应用类型的方法，用来判断当前应用程序的类型：
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;
springboot启动的运行方法，可以看到主要是各种运行环境的准备工作
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;
}
1、创建并启动计时监控类
创建并启动计时监控类，可以看到记录当前任务的名称，默认是空字符串，然后记录当前springboot应用启动的开始时间。
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、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：
/*
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、创建所有spring运行监听器并发布应用启动事件
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、初始化默认应用参数类
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、根据运行监听器和应用参数来准备spring环境
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、创建banner的打印类
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、创建应用的上下文:
根据不同哦那个的应用类型初始化不同的上下文应用类
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、准备异常报告器
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、准备应用上下文
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、刷新应用上下文
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、应用上下文刷新后置处理
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、停止计时监控类
计时监听器停止，并统计一些任务执行信息
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、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完成事件
触发所有SpringapplicationRunListener监听器的started事件方法
listeners.started(context);
void started(ConfigurableApplicationContext context) {
for (SpringApplicationRunListener listener : this.listeners) {
listener.started(context);
}
}
16、执行所有Runner执行器
执行所有applicationRunner和CommandLineRunner两种运行器
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、发布应用上下文就绪事件：触发所有springapplicationRunnListener将挺起的running事件方法
listeners.running(context);
void running(ConfigurableApplicationContext context) {
for (SpringApplicationRunListener listener : this.listeners) {
listener.running(context);
}
}
18、返回应用上下文
return context;
注意：
整个springboot框架中获取factorys文件的方式统一如下：
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;
}
spring.factory文件中的类的作用：
# 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