Spring Boot启动过程
2019-05-27 本文已影响0人
李小二的倔强
Spring Boot启动过程
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1. SpringApplication(ResourceLoader resourceLoader, Class<?>… primarySources) 是springboot的主启动方法
public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySources) {
this.resourceLoader = resourceLoader;
Assert.notNull(primarySources, "PrimarySources must not be null");
this.primarySources = new LinkedHashSet<>(Arrays.asList(primarySources));
// 1、判断web类型,此处是通过ClassUtils.isPresent()来读取类是否存在,决定环境类型
this.webApplicationType = WebApplicationType.deduceFromClasspath();
//2 给定类型,然后从spring.factories文件加载初始化器
setInitializers((Collection) getSpringFactoriesInstances(
ApplicationContextInitializer.class));
// 3、给定类型,然后从spring.factories文件加载初始化器
setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
// 使用StackTraceElement[] stackTrace = new RuntimeException().getStackTrace(),
// 获取堆栈信息,获取名称为main方法的全类名,赋值
this.mainApplicationClass = deduceMainApplicationClass();
}
1、WebApplicationType.deduceFromClasspath() 方法进去之后将会看见判断环境的方法
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;
}
ClassUtils.isPresent(className, null) 进入后将看到具体的forName方法
public static Class<?> forName(String name, @Nullable ClassLoader classLoader)
throws ClassNotFoundException, LinkageError {
Assert.notNull(name, "Name must not be null");
Class<?> clazz = resolvePrimitiveClassName(name);
if (clazz == null) {
clazz = commonClassCache.get(name);
}
if (clazz != null) {
return clazz;
}
// "java.lang.String[]" style arrays
if (name.endsWith(ARRAY_SUFFIX)) {
String elementClassName = name.substring(0, name.length() - ARRAY_SUFFIX.length());
Class<?> elementClass = forName(elementClassName, classLoader);
return Array.newInstance(elementClass, 0).getClass();
}
// "[Ljava.lang.String;" style arrays
if (name.startsWith(NON_PRIMITIVE_ARRAY_PREFIX) && name.endsWith(";")) {
String elementName = name.substring(NON_PRIMITIVE_ARRAY_PREFIX.length(), name.length() - 1);
Class<?> elementClass = forName(elementName, classLoader);
return Array.newInstance(elementClass, 0).getClass();
}
// "[[I" or "[[Ljava.lang.String;" style arrays
if (name.startsWith(INTERNAL_ARRAY_PREFIX)) {
String elementName = name.substring(INTERNAL_ARRAY_PREFIX.length());
Class<?> elementClass = forName(elementName, classLoader);
return Array.newInstance(elementClass, 0).getClass();
}
ClassLoader clToUse = classLoader;
if (clToUse == null) {
clToUse = getDefaultClassLoader();
}
try {
return Class.forName(name, false, clToUse);
}
catch (ClassNotFoundException ex) {
int lastDotIndex = name.lastIndexOf(PACKAGE_SEPARATOR);
if (lastDotIndex != -1) {
String innerClassName =
name.substring(0, lastDotIndex) + INNER_CLASS_SEPARATOR + name.substring(lastDotIndex + 1);
try {
return Class.forName(innerClassName, false, clToUse);
}
catch (ClassNotFoundException ex2) {
// Swallow - let original exception get through
}
}
throw ex;
}
}
2、进入getSpringFactoriesInstances( ApplicationContextInitializer.class) 方法后看到如下代码：
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;
}
createSpringFactoriesInstances(type, parameterTypes,
classLoader, args, names) 进入方法后得到如下方法：
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 {
Class<?> instanceClass = ClassUtils.forName(name, classLoader);
Assert.isAssignable(type, instanceClass);
Constructor<?> constructor = instanceClass
.getDeclaredConstructor(parameterTypes);
T instance = (T) BeanUtils.instantiateClass(constructor, args);
instances.add(instance);
}
catch (Throwable ex) {
throw new IllegalArgumentException(
"Cannot instantiate " + type + " : " + name, ex);
}
}
return instances;
}
3、同上2的源码
4、deduceMainApplicationClass() 进入方法得到如下方法：
private Class<?> deduceMainApplicationClass() {
try {
StackTraceElement[] stackTrace = new RuntimeException().getStackTrace();
for (StackTraceElement stackTraceElement : stackTrace) {
if ("main".equals(stackTraceElement.getMethodName())) {
return Class.forName(stackTraceElement.getClassName());
}
}
}
catch (ClassNotFoundException ex) {
// Swallow and continue
}
return null;
}
2.run(new Class<?>[] { primarySource }, args);
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，默认值为：true
configureHeadlessProperty();
// 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();
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);
configureIgnoreBeanInfo(environment);
// 7、创建 Banner 打印类
Banner printedBanner = printBanner(environment);
// 8、创建应用上下文
context = createApplicationContext();
// 9、准备异常报告器
exceptionReporters = getSpringFactoriesInstances(
SpringBootExceptionReporter.class,
new Class[] { ConfigurableApplicationContext.class }, context);
// 10、准备应用上下文
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
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完成事件
listeners.started(context);
// 16、执行所有 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;
}
3、源码如下：
设置系统属性 java.awt.headless 的值，默认值为：true
对于一个 Java 服务器来说经常要处理一些图形元素，例如地图的创建或者图形和图表等。这些API基本上总是需要运行一个X-server以便能使用AWT（Abstract Window Toolkit，抽象窗口工具集）。然而运行一个不必要的 X-server 并不是一种好的管理方式。有时你甚至不能运行 X-server,因此最好的方案是运行 headless 服务器，来进行简单的图像处理。
private static final String SYSTEM_PROPERTY_JAVA_AWT_HEADLESS = "java.awt.headless";
private boolean headless = true;
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类。
创建所有 Spring 运行监听器并发布应用启动事件
void starting();
void environmentPrepared(ConfigurableEnvironment environment);
void contextPrepared(ConfigurableApplicationContext context);
void contextLoaded(ConfigurableApplicationContext context);
void started(ConfigurableApplicationContext context);
void running(ConfigurableApplicationContext context);
void failed(ConfigurableApplicationContext context, Throwable exception);
public void starting() {
for (SpringApplicationRunListener listener : this.listeners) {
listener.starting();
}
}
this.initialMulticaster.multicastEvent(new ApplicationContextInitializedEvent(
this.application, this.args, context));
多路广播事件处理 :
multicastEvent(final ApplicationEvent event, @Nullable ResolvableType eventType)
-| invokeListener(listener, event)
-| doInvokeListener(listener, event)
-| listener.onApplicationEvent(event)
注 : onApplicationEvent(event),其实看到此方法就可以见到真正处理的代码了
private SpringApplicationRunListeners getRunListeners(String[] args) {
Class<?>[] types = new Class<?>[] { SpringApplication.class, String[].class };
return new SpringApplicationRunListeners(logger, getSpringFactoriesInstances(
SpringApplicationRunListener.class, types, this, args));
}
private void doInvokeListener(ApplicationListener listener, ApplicationEvent event) {
try {
listener.onApplicationEvent(event);
} catch (ClassCastException var6) {
String msg = var6.getMessage();
if(msg != null && !this.matchesClassCastMessage(msg, event.getClass())) {
throw var6;
}
Log logger = LogFactory.getLog(this.getClass());
if(logger.isDebugEnabled()) {
logger.debug("Non-matching event type for listener: " + listener, var6);
}
}
}
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;
}
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 {
Class<?> instanceClass = ClassUtils.forName(name, classLoader);
Assert.isAssignable(type, instanceClass);
Constructor<?> constructor = instanceClass
.getDeclaredConstructor(parameterTypes);
T instance = (T) BeanUtils.instantiateClass(constructor, args);
instances.add(instance);
}
catch (Throwable ex) {
throw new IllegalArgumentException(
"Cannot instantiate " + type + " : " + name, ex);
}
}
return instances;
}
SpringApplicationRunListeners(Log log,
Collection<? extends SpringApplicationRunListener> listeners) {
this.log = log;
this.listeners = new ArrayList<>(listeners);
}
6、根据运行监听器和应用参数来准备 Spring 环境
private ConfigurableEnvironment prepareEnvironment(
SpringApplicationRunListeners listeners,
ApplicationArguments applicationArguments) {
// 创建和配置环境
ConfigurableEnvironment environment = getOrCreateEnvironment();
//根据环境类和参数初始化环境
configureEnvironment(environment, applicationArguments.getSourceArgs());
//初始化监听器 与`4.1`节处理逻辑相似
listeners.environmentPrepared(environment);
bindToSpringApplication(environment);
if (!this.isCustomEnvironment) {
environment = new EnvironmentConverter(getClassLoader())
.convertEnvironmentIfNecessary(environment, deduceEnvironmentClass());
}
ConfigurationPropertySources.attach(environment);
return environment;
}
protected void configureEnvironment(ConfigurableEnvironment environment,
String[] args) {
if (this.addConversionService) {
ConversionService conversionService = ApplicationConversionService
.getSharedInstance();
environment.setConversionService(
(ConfigurableConversionService) conversionService);
}
configurePropertySources(environment, args);
configureProfiles(environment, args);
}
private void configureIgnoreBeanInfo(ConfigurableEnvironment environment) {
if (System.getProperty(
CachedIntrospectionResults.IGNORE_BEANINFO_PROPERTY_NAME) == null) {
Boolean ignore = environment.getProperty("spring.beaninfo.ignore",
Boolean.class, Boolean.TRUE);
System.setProperty(CachedIntrospectionResults.IGNORE_BEANINFO_PROPERTY_NAME,
ignore.toString());
}
}
7、创建 Banner 打印类
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、创建应用上下文
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
初始化应用上下文和异常报告集合
ConfigurableApplicationContext context = null;
新建异常报告集合 ,在9、准备异常报告器中准备完成
Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>();
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;
}
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 {
Class<?> instanceClass = ClassUtils.forName(name, classLoader);
Assert.isAssignable(type, instanceClass);
Constructor<?> constructor = instanceClass
.getDeclaredConstructor(parameterTypes);
T instance = (T) BeanUtils.instantiateClass(constructor, args);
instances.add(instance);
}
catch (Throwable ex) {
throw new IllegalArgumentException(
"Cannot instantiate " + type + " : " + name, ex);
}
}
return instances;
}
10、准备应用上下文
private void prepareContext(ConfigurableApplicationContext context,
ConfigurableEnvironment environment, SpringApplicationRunListeners listeners,
ApplicationArguments applicationArguments, Banner printedBanner) {
// // 设置环境
context.setEnvironment(environment);
// 回调方法，Spring容器创建之后做一些额外的事
postProcessApplicationContext(context);
//SpringApplication的的初始化器开始工作
applyInitializers(context);
// 遍历调用SpringApplicationRunListener的contextPrepared方法。
// 目前只是将这个事件广播器注册到Spring容器中
listeners.contextPrepared(context);
if (this.logStartupInfo) {
logStartupInfo(context.getParent() == null);
logStartupProfileInfo(context);
}
//添加特定于引导的单例bean
ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
beanFactory.registerSingleton("springApplicationArguments", applicationArguments);
if (printedBanner != null) {
beanFactory.registerSingleton("springBootBanner", printedBanner);
}
if (beanFactory instanceof DefaultListableBeanFactory) {
((DefaultListableBeanFactory) beanFactory)
.setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);
}
// 加载资源
Set<Object> sources = getAllSources();
Assert.notEmpty(sources, "Sources must not be empty");
// 读取主类数据loader.load();
load(context, sources.toArray(new Object[0]));
//遍历调用SpringApplicationRunListener的contextLoaded方法。
listeners.contextLoaded(context);
}
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());
}
}
在刷新上下文之前，将任何 ApplicationContextInitializer 应用于上下文。
protected void applyInitializers(ConfigurableApplicationContext context) {
for (ApplicationContextInitializer initializer : getInitializers()) {
Class<?> requiredType = GenericTypeResolver.resolveTypeArgument(
initializer.getClass(), ApplicationContextInitializer.class);
Assert.isInstanceOf(requiredType, context, "Unable to call initializer.");
initializer.initialize(context);
}
}
为了记录启动信息，子类可以重写以添加附加日志记录。
protected void logStartupInfo(boolean isRoot) {
if (isRoot) {
new StartupInfoLogger(this.mainApplicationClass)
.logStarting(getApplicationLog());
}
}
调用此函数以记录活动概要信息。
protected void logStartupProfileInfo(ConfigurableApplicationContext context) {
Log log = getApplicationLog();
if (log.isInfoEnabled()) {
String[] activeProfiles = context.getEnvironment().getActiveProfiles();
if (ObjectUtils.isEmpty(activeProfiles)) {
String[] defaultProfiles = context.getEnvironment().getDefaultProfiles();
log.info("No active profile set, falling back to default profiles: "
+ StringUtils.arrayToCommaDelimitedString(defaultProfiles));
}
else {
log.info("The following profiles are active: "
+ StringUtils.arrayToCommaDelimitedString(activeProfiles));
}
}
}
将bean加载到应用程序上下文中。
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();
}
/**
* 将源代码加载到阅读器中。
* @return the number of loaded beans
*/
public int load() {
int count = 0;
for (Object source : this.sources) {
count += load(source);
}
return count;
}
11、刷新应用上下文
private void refreshContext(ConfigurableApplicationContext context) {
refresh(context);
if (this.registerShutdownHook) {
try {
context.registerShutdownHook();
}
catch (AccessControlException ex) {
// 在某些环境中是不允许的。
}
}
}
返回静态指定的Applicationisteners列表。
public void refresh() throws BeansException, IllegalStateException {
Object var1 = this.startupShutdownMonitor;
synchronized(this.startupShutdownMonitor) {
// 准备好刷新上下文
this.prepareRefresh();
// 告诉子类刷新内部bean工厂。
ConfigurableListableBeanFactory beanFactory = this.obtainFreshBeanFactory();
// 准备bean工厂，以便在此上下文中使用。
this.prepareBeanFactory(beanFactory);
try {
// 允许在上下文子类中对bean工厂进行后处理。
this.postProcessBeanFactory(beanFactory);
// 调用上下文中注册为bean的工厂处理器。
this.invokeBeanFactoryPostProcessors(beanFactory);
// 注册拦截bean创建的bean处理器。
this.registerBeanPostProcessors(beanFactory);
// 初始化此上下文的消息源。
this.initMessageSource();
// 初始化此上下文的事件多播程序
this.initApplicationEventMulticaster();
// 在特定上下文子类中初始化其他特殊bean。
this.onRefresh();
// 检查侦听器bean并注册它们。
this.registerListeners();
// 实例化所有剩余的(非惰性初始化)单例。
this.finishBeanFactoryInitialization(beanFactory);
// 最后一步:发布相应的事件。
this.finishRefresh();
} catch (BeansException var9) {
if(this.logger.isWarnEnabled()) {
this.logger.warn("Exception encountered during context initialization - cancelling refresh attempt: " + var9);
}
// 销毁已经创建的单例，以避免挂起资源。
this.destroyBeans();
// 重置“活跃”的旗帜。
this.cancelRefresh(var9);
// 将异常传播给调用者。
throw var9;
} finally {
// 重置Spring核心中的公共内省缓存，因为我们可能再也不需要单例bean的元数据了……
this.resetCommonCaches();
}
}
}
设置Spring容器的启动时间，撤销关闭状态，开启活跃状态。
初始化属性源信息(Property)
验证环境信息里一些必须存在的属性
protected void prepareRefresh() {
this.startupDate = System.currentTimeMillis();
this.closed.set(false);
this.active.set(true);
if(this.logger.isDebugEnabled()) {
if(this.logger.isTraceEnabled()) {
this.logger.trace("Refreshing " + this);
} else {
this.logger.debug("Refreshing " + this.getDisplayName());
}
}
this.initPropertySources();
this.getEnvironment().validateRequiredProperties();
if(this.earlyApplicationListeners == null) {
this.earlyApplicationListeners = new LinkedHashSet(this.applicationListeners);
} else {
this.applicationListeners.clear();
this.applicationListeners.addAll(this.earlyApplicationListeners);
}
this.earlyApplicationEvents = new LinkedHashSet();
}
1.设置classloader(用于加载bean)，设置表达式解析器(解析bean定义中的一些表达式)，添加属性编辑注册器(注册属性编辑器)
2.添加ApplicationContextAwareProcessor这个BeanPostProcessor。取消ResourceLoaderAware、ApplicationEventPublisherAware、MessageSourceAware、ApplicationContextAware、EnvironmentAware这5个接口的自动注入。因为ApplicationContextAwareProcessor把这5个接口的实现工作做了
3.设置特殊的类型对应的bean。BeanFactory对应刚刚获取的BeanFactory；ResourceLoader、ApplicationEventPublisher、ApplicationContext这3个接口对应的bean都设置为当前的Spring容器
4.注入一些其它信息的bean，比如environment、systemProperties等
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
//设置classloader(用于加载bean)
beanFactory.setBeanClassLoader(this.getClassLoader());
设置表达式解析器(解析bean定义中的一些表达式)
beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
//添加属性编辑注册器(注册属性编辑器)
beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, this.getEnvironment()));
//添加ApplicationContextAwareProcessor这个BeanPostProcessor。
//取消ResourceLoaderAware、ApplicationEventPublisherAware、MessageSourceAware、ApplicationContextAware、
//EnvironmentAware这5个接口的自动注入。
//因为ApplicationContextAwareProcessor把这5个接口的实现工作做了
beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
beanFactory.registerResolvableDependency(ResourceLoader.class, this);
beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
beanFactory.registerResolvableDependency(ApplicationContext.class, this);
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));
//注入一些其它信息的bean，比如environment、systemProperties等
if(beanFactory.containsBean("loadTimeWeaver")) {
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}
if(!beanFactory.containsLocalBean("environment")) {
beanFactory.registerSingleton("environment", this.getEnvironment());
}
if(!beanFactory.containsLocalBean("systemProperties")) {
beanFactory.registerSingleton("systemProperties", this.getEnvironment().getSystemProperties());
}
if(!beanFactory.containsLocalBean("systemEnvironment")) {
beanFactory.registerSingleton("systemEnvironment", this.getEnvironment().getSystemEnvironment());
}
}
invokeBeanFactoryPostProcessors(beanFactory)—>
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory,getBeanFactoryPostProcessors())—>
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry)
public static void invokeBeanFactoryPostProcessors(
ConfigurableListableBeanFactory beanFactory, List<BeanFactoryPostProcessor> beanFactoryPostProcessors) {
// 如果有的话，首先调用beandefinition reqistrypostprocessor。
Set<String> processedBeans = new HashSet<>();
if (beanFactory instanceof BeanDefinitionRegistry) {
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
List<BeanFactoryPostProcessor> regularPostProcessors = new ArrayList<>();
List<BeanDefinitionRegistryPostProcessor> registryProcessors = new ArrayList<>();
for (BeanFactoryPostProcessor postProcessor : beanFactoryPostProcessors) {
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
BeanDefinitionRegistryPostProcessor registryProcessor =
(BeanDefinitionRegistryPostProcessor) postProcessor;
registryProcessor.postProcessBeanDefinitionRegistry(registry);
registryProcessors.add(registryProcessor);
}
else {
regularPostProcessors.add(postProcessor);
}
}
// 不要在这里初始化factorvbean:我们需要不初始化所有常规bean，让bean工厂后处理程序应用于它们!
// 将实现erioritvordered的beandefinition registrypostprocessor分开。点的，还有其他的。
List<BeanDefinitionRegistryPostProcessor> currentRegistryProcessors = new ArrayList<>();
// 首先，调用实现priorityorated的beandefinition registrypostprocessor。
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
// 接下来，调用实现Ordered的beandefinitionrecistrypostprocessor。
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class)) {
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
// 最后，调用所有其他beandefinitionregistrypostprocessor，直到没有其他bean出现
boolean reiterate = true;
while (reiterate) {
reiterate = false;
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
for (String ppName : postProcessorNames) {
if (!processedBeans.contains(ppName)) {
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
reiterate = true;
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
//链路调用此方法
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
}
// 现在，调用到目前为止处理的所有处理器的postProcessBeanFactory回调。
invokeBeanFactoryPostProcessors(registryProcessors, beanFactory);
invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
}
else {
// 使用上下文实例调用reqistered工厂处理器。
invokeBeanFactoryPostProcessors(beanFactoryPostProcessors, beanFactory);
}
// 不要在这里初始化factorybean:我们需要不初始化所有reqular bean，让pean factory后处理程序应用于它们!
String[] postProcessorNames =
beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
// 将实现优先化ed的beanfactorypostprocessor与其他处理器分开。
List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
List<String> orderedPostProcessorNames = new ArrayList<>();
List<String> nonOrderedPostProcessorNames = new ArrayList<>();
for (String ppName : postProcessorNames) {
if (processedBeans.contains(ppName)) {
// 跳过-已经在上面的第一阶段处理
}
else if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) {
priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
orderedPostProcessorNames.add(ppName);
}
else {
nonOrderedPostProcessorNames.add(ppName);
}
}
// 首先，调用实现priorityordering的beanfactorypostprocessor。
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);
// 接下来，调用实现ordered的beanfactorypostprocessor。
List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<>();
for (String postProcessorName : orderedPostProcessorNames) {
orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
sortPostProcessors(orderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);
// 最后，调用所有其他beanfactorypostprocessor。
List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<>();
for (String postProcessorName : nonOrderedPostProcessorNames) {
nonOrderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);
// 清除缓存的合并bean定义，因为后处理程序可能修改了原始元数据，例如替换值中的占位符……
beanFactory.clearMetadataCache();
}
/**
* 调用给定的BeanDefinitionReqistryPostProcessor bean。
*/
private static void invokeBeanDefinitionRegistryPostProcessors(
Collection<? extends BeanDefinitionRegistryPostProcessor> postProcessors, BeanDefinitionRegistry registry) {
for (BeanDefinitionRegistryPostProcessor postProcessor : postProcessors) {
postProcessor.postProcessBeanDefinitionRegistry(registry);
}
}
postProcessor.postProcessBeanDefinitionRegistry(registry)—>
// ConfigurationClassPostProcessor类中的方法
public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) {
int registryId = System.identityHashCode(registry);
if(this.registriesPostProcessed.contains(Integer.valueOf(registryId))) {
throw new IllegalStateException("postProcessBeanDefinitionRegistry already called on this post-processor against " + registry);
} else if(this.factoriesPostProcessed.contains(Integer.valueOf(registryId))) {
throw new IllegalStateException("postProcessBeanFactory already called on this post-processor against " + registry);
} else {
this.registriesPostProcessed.add(Integer.valueOf(registryId));
this.processConfigBeanDefinitions(registry);
}
}
processConfigBeanDefinitions(registry)[创建config bean]—>
**读取主类包中的@Component注解 : **
ComponentScanAnnotationParser读取@ComponentScan注解,通过parse()加载packages属性.
Set<BeanDefinitionHolder> parse(AnnotationAttributes componentScan, final String declaringClass)
Set<BeanDefinitionHolder> parse(AnnotationAttributes componentScan, final String declaringClass)
declaringClass是传入的主类,默认会读取该类的包位置
public void processConfigBeanDefinitions(BeanDefinitionRegistry registry) {
List<BeanDefinitionHolder> configCandidates = new ArrayList();
String[] candidateNames = registry.getBeanDefinitionNames();
String[] var4 = candidateNames;
int var5 = candidateNames.length;
for(int var6 = 0; var6 < var5; ++var6) {
String beanName = var4[var6];
BeanDefinition beanDef = registry.getBeanDefinition(beanName);
if(!ConfigurationClassUtils.isFullConfigurationClass(beanDef) && !ConfigurationClassUtils.isLiteConfigurationClass(beanDef)) {
if(ConfigurationClassUtils.checkConfigurationClassCandidate(beanDef, this.metadataReaderFactory)) {
configCandidates.add(new BeanDefinitionHolder(beanDef, beanName));
}
} else if(this.logger.isDebugEnabled()) {
this.logger.debug("Bean definition has already been processed as a configuration class: " + beanDef);
}
}
if(!configCandidates.isEmpty()) {
configCandidates.sort((bd1, bd2) -> {
int i1 = ConfigurationClassUtils.getOrder(bd1.getBeanDefinition());
int i2 = ConfigurationClassUtils.getOrder(bd2.getBeanDefinition());
return Integer.compare(i1, i2);
});
SingletonBeanRegistry sbr = null;
if(registry instanceof SingletonBeanRegistry) {
sbr = (SingletonBeanRegistry)registry;
if(!this.localBeanNameGeneratorSet) {
BeanNameGenerator generator = (BeanNameGenerator)sbr.getSingleton("org.springframework.context.annotation.internalConfigurationBeanNameGenerator");
if(generator != null) {
this.componentScanBeanNameGenerator = generator;
this.importBeanNameGenerator = generator;
}
}
}
if(this.environment == null) {
this.environment = new StandardEnvironment();
}
ConfigurationClassParser parser = new ConfigurationClassParser(this.metadataReaderFactory, this.problemReporter, this.environment, this.resourceLoader, this.componentScanBeanNameGenerator, registry);
Set<BeanDefinitionHolder> candidates = new LinkedHashSet(configCandidates);
HashSet alreadyParsed = new HashSet(configCandidates.size());
do {
parser.parse(candidates);
parser.validate();
Set<ConfigurationClass> configClasses = new LinkedHashSet(parser.getConfigurationClasses());
configClasses.removeAll(alreadyParsed);
if(this.reader == null) {
this.reader = new ConfigurationClassBeanDefinitionReader(registry, this.sourceExtractor, this.resourceLoader, this.environment, this.importBeanNameGenerator, parser.getImportRegistry());
}
this.reader.loadBeanDefinitions(configClasses);
alreadyParsed.addAll(configClasses);
candidates.clear();
if(registry.getBeanDefinitionCount() > candidateNames.length) {
String[] newCandidateNames = registry.getBeanDefinitionNames();
Set<String> oldCandidateNames = new HashSet(Arrays.asList(candidateNames));
Set<String> alreadyParsedClasses = new HashSet();
Iterator var12 = alreadyParsed.iterator();
while(var12.hasNext()) {
ConfigurationClass configurationClass = (ConfigurationClass)var12.next();
alreadyParsedClasses.add(configurationClass.getMetadata().getClassName());
}
String[] var23 = newCandidateNames;
int var24 = newCandidateNames.length;
for(int var14 = 0; var14 < var24; ++var14) {
String candidateName = var23[var14];
if(!oldCandidateNames.contains(candidateName)) {
BeanDefinition bd = registry.getBeanDefinition(candidateName);
if(ConfigurationClassUtils.checkConfigurationClassCandidate(bd, this.metadataReaderFactory) && !alreadyParsedClasses.contains(bd.getBeanClassName())) {
candidates.add(new BeanDefinitionHolder(bd, candidateName));
}
}
}
candidateNames = newCandidateNames;
}
} while(!candidates.isEmpty());
if(sbr != null && !sbr.containsSingleton(IMPORT_REGISTRY_BEAN_NAME)) {
sbr.registerSingleton(IMPORT_REGISTRY_BEAN_NAME, parser.getImportRegistry());
}
if(this.metadataReaderFactory instanceof CachingMetadataReaderFactory) {
((CachingMetadataReaderFactory)this.metadataReaderFactory).clearCache();
}
}
}
ComponentScanAnnotationParser读取@ComponentScan注解,通过parse()加载packages属性.
public void parse(Set<BeanDefinitionHolder> configCandidates) {
Iterator var2 = configCandidates.iterator();
while(var2.hasNext()) {
BeanDefinitionHolder holder = (BeanDefinitionHolder)var2.next();
BeanDefinition bd = holder.getBeanDefinition();
try {
if(bd instanceof AnnotatedBeanDefinition) {
this.parse(((AnnotatedBeanDefinition)bd).getMetadata(), holder.getBeanName());
} else if(bd instanceof AbstractBeanDefinition && ((AbstractBeanDefinition)bd).hasBeanClass()) {
this.parse(((AbstractBeanDefinition)bd).getBeanClass(), holder.getBeanName());
} else {
this.parse(bd.getBeanClassName(), holder.getBeanName());
}
} catch (BeanDefinitionStoreException var6) {
throw var6;
} catch (Throwable var7) {
throw new BeanDefinitionStoreException("Failed to parse configuration class [" + bd.getBeanClassName() + "]", var7);
}
}
this.deferredImportSelectorHandler.process();
}
protected final void parse(AnnotationMetadata metadata, String beanName) throws IOException {
processConfigurationClass(new ConfigurationClass(metadata, beanName));
}
protected void processConfigurationClass(ConfigurationClass configClass) throws IOException {
if (this.conditionEvaluator.shouldSkip(configClass.getMetadata(), ConfigurationPhase.PARSE_CONFIGURATION)) {
return;
}
ConfigurationClass existingClass = this.configurationClasses.get(configClass);
if (existingClass != null) {
if (configClass.isImported()) {
if (existingClass.isImported()) {
existingClass.mergeImportedBy(configClass);
}
// 否则忽略新导入的配置类;现有的非导入类覆盖它。
return;
}
else {
// 找到显式bean定义，可能替换导入。
// 让我们把旧的拿掉，换上新的。
this.configurationClasses.remove(configClass);
this.knownSuperclasses.values().removeIf(configClass::equals);
}
}
// 递归地处理配置类及其超类层次结构。
SourceClass sourceClass = asSourceClass(configClass);
do {
sourceClass = doProcessConfigurationClass(configClass, sourceClass);
}
while (sourceClass != null);
this.configurationClasses.put(configClass, configClass);
}
12、应用上下文刷新后置处理
在刷新上下文之后调用。
protected void afterRefresh(ConfigurableApplicationContext context,
ApplicationArguments args) {
}
13、停止计时监控类
停止当前任务。如果在不调用至少一对的情况下调用计时方法，则结果是未定义的
public void stop() throws IllegalStateException {
if (this.currentTaskName == null) {
throw new IllegalStateException("Can't stop StopWatch: it's not running");
}
long lastTime = System.currentTimeMillis() - this.startTimeMillis;
this.totalTimeMillis += 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
public void logStarted(Log log, StopWatch stopWatch) {
if (log.isInfoEnabled()) {
log.info(getStartedMessage(stopWatch));
}
}
private StringBuilder getStartedMessage(StopWatch stopWatch) {
StringBuilder message = new StringBuilder();
message.append("Started ");
message.append(getApplicationName());
message.append(" in ");
message.append(stopWatch.getTotalTimeSeconds());
try {
double uptime = ManagementFactory.getRuntimeMXBean().getUptime() / 1000.0;
message.append(" seconds (JVM running for " + uptime + ")");
}
catch (Throwable ex) {
// No JVM time available
}
return message;
}
15、发布应用上下文启动完成事件
default void publishEvent(ApplicationEvent event) {
this.publishEvent((Object)event);
}
16、执行所有 Runner 运行器
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);
}
}
}
private void callRunner(ApplicationRunner runner, ApplicationArguments args) {
try {
(runner).run(args);
}
catch (Exception ex) {
throw new IllegalStateException("Failed to execute ApplicationRunner", ex);
}
}
