山东住房和城乡建设厅网站首页,报告的英文,wordpress缩略图尺寸,东莞常平哪里好玩参考文章#xff1a;SpringBoot启动流程系列讲解 参考视频#xff1a;SpringBoot启动流程 吐血推荐视频#xff1a;史上最完整的Spring启动流程 超级好文#xff1a;SpringBoot执行原理 参考文章#xff1a;SpringBoot资源接口ResourceLoader和Resource学习 参考文章…参考文章SpringBoot启动流程系列讲解 参考视频SpringBoot启动流程 吐血推荐视频史上最完整的Spring启动流程 超级好文SpringBoot执行原理 参考文章SpringBoot资源接口ResourceLoader和Resource学习 参考文章到底什么是上下文Context 参考文章超级好文 参考文章这个系列的文章让我自愧不如痛删了原来2W字的内容 文章目录Spring Boot启动流程服务构建环境准备容器创建填充容器非常重要的函数getSpringFactoriesInstancesgetClassLoader()deduceMainApplicationClass()getRunListeners(String[] args)SpringApplicationRunListeners.starting()prepareEnvironmentSpringApplicationRunListeners, applicationArgumentsprepareContext()refreshContextrefreshContext.refresh.obtainFreshBeanFactory()refreshContext.refresh.finishBeanFactoryInitialization(beanFactory)非常重要的类ResourceLoader总结**4. 填充容器就是容器创建的refreshContext**Spring Boot启动流程
服务构建
//SpringApplication类
//只列出几个重要的字段和方法
public class SpringApplication {//SpringApplication默认web容器类public static final String DEFAULT_SERVLET_WEB_CONTEXT_CLASS org.springframework.boot. web.servlet.context.AnnotationConfigServletWebServerApplicationContext;//banner名称,默认为banner.txtpublic static final String BANNER_LOCATION_PROPERTY_VALUE SpringApplicationBannerPrinter.DEFAULT_BANNER_LOCATION;//banner位置key,默认为spring.banner.locationpublic static final String BANNER_LOCATION_PROPERTY SpringApplicationBannerPrinter.BANNER_LOCATION_PROPERTY;//调用main函数的类,也就是YanggxApplication.classprivate Class? mainApplicationClass;//bean名称生成器执行结果为nullprivate BeanNameGenerator beanNameGenerator;//spring的环境,我们使用的是ServletWeb环境private ConfigurableEnvironment environment;//web类型执行结果为SERVLETprivate WebApplicationType webApplicationType;//Application初始化器springboot启动过程中执行其initialize方法private ListApplicationContextInitializer? initializers;//Application监听器springboot启动过程执行其onApplicationEvent方法private ListApplicationListener? listeners;/*** SpringApplication构造函数* param resourceLoader 资源加载器的策略接口,传参null,* param primarySources 传参YanggxApplication.class*/public SpringApplication(ResourceLoader resourceLoader, Class?... primarySources) {//执行结果nullthis.resourceLoader resourceLoader;Assert.notNull(primarySources, PrimarySources must not be null);//Set去重primarySources:[com.yanggx.spring.YanggxApplication.class]this.primarySources new LinkedHashSet(Arrays.asList(primarySources));// 判断当前模块web类型webApplicationType:SERVLETthis.webApplicationType WebApplicationType.deduceFromClasspath();// 加载Application初始化器// 获取所有META-INF/spring.factories文件中维护的ApplicationContextInitializer子类列表// org.springframework.boot.context.ConfigurationWarningsApplicationContextInitializer// org.springframework.boot.context.ContextIdApplicationContextInitializer // org.springframework.boot.context.config.DelegatingApplicationContextInitializer // org.springframework.boot.web.context.ServerPortInfoApplicationContextInitializer // org.springframework.boot.autoconfigure.logging.ConditionEvaluationReportLoggingListenersetInitializers((Collection) getSpringFactoriesInstances(ApplicationContextInitializer.class));// 3.3 加载Application监听器// 获取所有META-INF/spring.factories文件中维护的ApplicationListener子类列表// 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// org.springframework.boot.autoconfigure.BackgroundPreinitializer// 加载的这些类都是ApplicationListener的子类setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));// 3.4 找到启动类// 抛出一个RuntimeException,然后通过堆栈信息找到启动类//mainApplicationClass: com.yanggx.spring.YanggxApplication.classthis.mainApplicationClass deduceMainApplicationClass();}
}环境准备
public class SpringApplication {public ConfigurableApplicationContext run(String... args) {//实例化一个StopWatch实例, 监控项目运行时间StopWatch stopWatch new StopWatch();stopWatch.start();//初始化Spring上下文ConfigurableApplicationContext context null;//初始化错误报告参数CollectionSpringBootExceptionReporter exceptionReporters new ArrayList();//配置headless,在没有显示器,鼠标,键盘的情况下,仍然可以调用显示,输入输出的方法configureHeadlessProperty();//1. 发布Spring启动事件SpringApplicationRunListeners listeners getRunListeners(args);listeners.starting();try {/*2. 这一步的主要作用是处理启动类main函数的参数, 将其封装为一个 DefaultApplicationArguments对象, 为prepareEnvironment()提供参数*/ApplicationArguments applicationArguments new DefaultApplicationArguments(args);//3.这一步的主要作用按顺序加载命令行参数, 系统参数和外部配置文件, 创建并配置Web环境ConfigurableEnvironment environment prepareEnvironment(listeners, applicationArguments); configureIgnoreBeanInfo(environment);//4. 打印Banner图Banner printedBanner printBanner(environment);//....}容器创建
public ConfigurableApplicationContext run(String... args) {//步骤1: 根据switch创建context分别有SERVLET、REACTIVE、NONE并且注册了Bean后置处理器context createApplicationContext();//步骤2: BeanFactory是在这里创建的context.setApplicationStartup(this.applicationStartup);//步骤2: prepareContext()准备应用上下文prepareContext(context, environment, listeners, applicationArguments, printedBanner);//步骤3: refreshContext()刷新应用上下文BeanDefinition和BeanFactory都是在这里创建的refreshContext(context);//步骤4: 刷新完成该方法是拓展接口用户可以自定义操作逻辑afterRefresh(context, applicationArguments);//步骤6: 发布Application开始事件listeners.started(context);//步骤7: 执行Runners,用于调用项目中自定义的执行器xxxRunner类//在项目启动完成后立即执行这些操作只在服务启动时执行一次callRunners(context, applicationArguments);//步骤8: 发布Application准备事件listeners.running(context);return context;
}填充容器
/*** 抽象父类ApplicationContext*/
public abstract class AbstractApplicationContext extends DefaultResourceLoaderimplements ConfigurableApplicationContext {Overridepublic void refresh() throws BeansException, IllegalStateException {synchronized (this.startupShutdownMonitor) {//刷新前操作例如清空缓存、初始化占位符prepareRefresh();//获取并刷新beanFactory创建BeanFactory和BeanDefinitionConfigurableListableBeanFactory beanFactory obtainFreshBeanFactory();//设置beanFactory配置各种beanFactory.xxx属性prepareBeanFactory(beanFactory);//beanFactory的后置处理器注册与Servlet相关的特殊Bean注册beanDefinitionpostProcessBeanFactory(beanFactory);/*BeanFactoryPostProcessor是一个接口, 处理beanFactory中所有的bean, 在所有的beanDefinition加载完成之后, BeanFactoryPostProcessor可以对beanDefinition进行属性的修改, 之后再进行bean实例化*/invokeBeanFactoryPostProcessors(beanFactory);//beanFactory注册后置处理器对bean实例的增强registerBeanPostProcessors(beanFactory);//初始化messageSourceinitMessageSource();//初始化Application事件发布器initApplicationEventMulticaster();//初始化其他特殊的bean例如实例化了TomcatWebServeronRefresh();//注册监听器registerListeners();//完成beanFactory初始化finishBeanFactoryInitialization(beanFactory);//完成刷新,发布完成事件实例化了所有beanfinishRefresh(); }
}非常重要的函数
getSpringFactoriesInstances private T CollectionT getSpringFactoriesInstances(ClassT type, Class?[] parameterTypes, Object... args) {ClassLoader classLoader this.getClassLoader();SetString names new LinkedHashSet(SpringFactoriesLoader.loadFactoryNames(type, classLoader));ListT instances this.createSpringFactoriesInstances(type, parameterTypes, classLoader, args, names);AnnotationAwareOrderComparator.sort(instances);return instances;}public static ListString loadFactoryNames(Class? factoryType, Nullable ClassLoader classLoader) {//主要获取spring.factories中的key,key对应接口全名String factoryTypeName factoryType.getName();//筛选Map中key为factoryTypeName对应放到list返回 return loadSpringFactories(classLoader).getOrDefault(factoryTypeName, Collections.emptyList());}//会把Spring.factories文件中所有键值对放到Map中其实就是缓存//classLoader参数就是META-INF/spring.factories加载器private static MapString, ListString loadSpringFactories(Nullable ClassLoader classLoader) {//如果缓存已经有Spring.factories那就从缓存中拿MultiValueMapString, String result cache.get(classLoader);if (result ! null) {return result;}//如果缓存中没有Spring.factories那就从重新加载到缓存EnumerationURL urls (classLoader ! null ?// FACTORIES_RESOURCE_LOCATION META-INF/spring.factories 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;}private T ListT createSpringFactoriesInstances(ClassT type, Class?[] parameterTypes,ClassLoader classLoader, Object[] args, SetString names) {ListT instances new ArrayList(names.size());for (String name : names) {try {//通过反射机制创建实例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;}总结 loadSpringFactories(Nullable ClassLoader classLoader)判断缓存是否有Spring.factories文件如果有就提取整个spring.factories。如果没有就加载到缓存再提取。loadFactoryNames(Class? factoryType, Nullable ClassLoader classLoader)从spring.factories文件中获取指定factoryTypecreateSpringFactoriesInstances(Class type, Class?[] parameterTypes, ClassLoader classLoader, Object[] args, Set names)将loadFactoryNames返回的factoryType通过反射机制实例化getSpringFactoriesInstances(Class type, Class?[] parameterTypes, Object… args)获取createSpringFactoriesInstances返回的实例instances返回实例 getClassLoader() 我们都知道java程序写好以后是以.java文本文件的文件存在磁盘上然后我们通过(bin/javac.exe)编译命令把.java文件编译成.class文件字节码文件并存在磁盘上。 但是程序要运行首先一定要把.class文件加载到JVM内存中才能使用的我们所讲的classLoader,就是负责把磁盘上的.class文件加载到JVM内存中你可以认为每一个Class对象拥有磁盘上的那个.class字节码内容,每一个class对象都有一个getClassLoader()方法得到是谁把我从.class文件加载到内存中变成Class对象的 deduceMainApplicationClass()
private Class? deduceMainApplicationClass() {try {//通过一个RuntimeException,获取器堆栈信息StackTraceElement[] stackTrace new RuntimeException().getStackTrace();for (StackTraceElement stackTraceElement : stackTrace) {if (main.equals(stackTraceElement.getMethodName())) {//堆栈中包含main方法,实例化一个该类的对象return Class.forName(stackTraceElement.getClassName());}}}catch (ClassNotFoundException ex) { }return null;
}getRunListeners(String[] args) //当前只能获取SpringApplicationRunListener子类列表EventPublishingRunListenerprivate SpringApplicationRunListeners getRunListeners(String[] args) {Class?[] types new Class?[] { SpringApplication.class, String[].class };return new SpringApplicationRunListeners(logger, getSpringFactoriesInstances(SpringApplicationRunListener.class, types, this, args));}SpringApplicationRunListeners.starting()
//该SpringApplicationRunListeners存在多个子类在下面starting方法中会调用对应子类的starting方法
class SpringApplicationRunListeners {//发布启动事件public void starting() {for (SpringApplicationRunListener listener : this.listeners) {//目前调用EventPublishingRunListener的starting方法listener.starting();}}//其他事件都是相同的代码
}//不仅仅是ApplicationListeners存在很多子类EventPublishingRunListener也有很多子类
public class EventPublishingRunListener implements SpringApplicationRunListener, Ordered {//SpringApplication对象private final SpringApplication application;//命令函参数private final String[] args;//事件广播器private final SimpleApplicationEventMulticaster initialMulticaster;public EventPublishingRunListener(SpringApplication application, String[] args) {this.application application;this.args args;this.initialMulticaster new SimpleApplicationEventMulticaster();// 通过application.getListeners(),获取到Listener列表// ConfigFileApplicationListener// AnsiOutputApplicationListener// LoggingApplicationListener// ClasspathLoggingApplicationListener// BackgroundPreinitializer// DelegatingApplicationListener// ParentContextCloserApplicationListener// ClearCachesApplicationListener// FileEncodingApplicationListener// LiquibaseServiceLocatorApplicationListenerfor (ApplicationListener? listener : application.getListeners()) {//将listener添加到事件广播器initialMulticasterthis.initialMulticaster.addApplicationListener(listener);}}Overridepublic void starting() {// 广播器广播ApplicationStartingEvent事件this.initialMulticaster.multicastEvent(new ApplicationStartingEvent(this.application, this.args));}//其他事件发布都是相同的代码//...
}public class SimpleApplicationEventMulticaster extends AbstractApplicationEventMulticaster {public void multicastEvent(final ApplicationEvent event, Nullable ResolvableType eventType) {ResolvableType type (eventType ! null ? eventType : resolveDefaultEventType(event));//调用父类getApplicationListeners方法//遍历所有支持ApplicationStartingEvent事件的监听器//LoggingApplicationListener//BackgroundPreinitializer//DelegatingApplicationListener//LiquibaseServiceLocatorApplicationListenerfor (final ApplicationListener? listener : getApplicationListeners(event, type)) {//此时的executor为nullExecutor executor getTaskExecutor();if (executor ! null) {executor.execute(() - invokeListener(listener, event));}else {//调用listenerinvokeListener(listener, event);}}}
}protected void invokeListener(ApplicationListener? listener, ApplicationEvent event) {ErrorHandler errorHandler this.getErrorHandler();if (errorHandler ! null) {try {this.doInvokeListener(listener, event);} catch (Throwable var5) {errorHandler.handleError(var5);}} else {this.doInvokeListener(listener, event);}}private void doInvokeListener(ApplicationListener listener, ApplicationEvent event) {//调用listener的onApplicationEvent方法listener.onApplicationEvent(event);}onApplicationEvent(event){到这里就不再深究了这个方法有三十个实现类操作基本上就是绑定环境设置参数等等
}总结 SpringApplicationRunListeners.starting调用了EventPublishingRunListener.startingEventPublishingRunListener.starting调用了广播器initialMulticaster.multicastEvent发布SpringApplication启动事件initialMulticaster.multicastEvent分别调用了LoggingApplicationListener、BackgroundPreinitializer、DelegatingApplicationListener、LiquibaseServiceLocatorApplicationListener的invokeListener方法 invokeListener——doInvokeListener——onApplicationEvent——设置参数、绑定环境等等 prepareEnvironmentSpringApplicationRunListeners, applicationArguments private ConfigurableEnvironment prepareEnvironment(SpringApplicationRunListeners listeners,ApplicationArguments applicationArguments) {//获取或者创建环境根据switch判断选择SERVLET、REACTIVE、NONE类型ConfigurableEnvironment environment getOrCreateEnvironment();//配置环境为environment配置“共享的类型转换服务”即A数据类型变成B数据类型 //然后将defaultProperties和args分别添加到environment的propertySources中configureEnvironment(environment, applicationArguments.getSourceArgs());//发布环境准备事件listeners.environmentPrepared(environment);//如果指定了main函数,那么会将当前环境绑定到指定的SpringApplication中bindToSpringApplication(environment);if (!this.isCustomEnvironment) {//环境转换如果environment.class和模块EnvironmentClass()不一致就转换成一样的environment new EnvironmentConverter(getClassLoader()).convertEnvironmentIfNecessary(environment, deduceEnvironmentClass());}//将环境依附到PropertySourcesConfigurationPropertySources.attach(environment);return environment;}prepareContext() private void prepareContext(ConfigurableApplicationContext context,ConfigurableEnvironment environment, SpringApplicationRunListeners listeners,ApplicationArguments applicationArguments, Banner printedBanner) {//设置context环境统一ApplicationContext与Application.environment一致context.setEnvironment(environment);//设置ApplicationContext.beanNameGenerator、resourceLoader、classLoader、类型转换服务postProcessApplicationContext(context);//获取6个初始化器并执行初始化方法例如设置元数据、配置警告、获取应用名称applyInitializers(context);//发布contextPrepared事件listeners.contextPrepared(context);if (this.logStartupInfo) {//配置了info日志//打印启动和profile日志logStartupInfo(context.getParent() null);logStartupProfileInfo(context);}//获取到DefaultListableBeanFactory实例ConfigurableListableBeanFactory beanFactory context.getBeanFactory();//注册名为springApplicationArguments,值为applicationArguments的单例beanbeanFactory.registerSingleton(springApplicationArguments, applicationArguments);//banner不为空,那么注册名为springBootBanner,值为printedBanner的单例beanif (printedBanner ! null) {beanFactory.registerSingleton(springBootBanner, printedBanner);}if (beanFactory instanceof DefaultListableBeanFactory) {//allowBeanDefinitionOverriding默认为false((DefaultListableBeanFactory) beanFactory).setAllowBeanDefinitionOverriding(this.allowBeanDefinitionOverriding);}// 获取sources列表,获取到我们的YanggxApplication.classSetObject sources getAllSources();Assert.notEmpty(sources, Sources must not be empty);//初始化bean加载器,并加载bean到应用上下文load(context, sources.toArray(new Object[0]));//发布contextLoaded事件listeners.contextLoaded(context);}refreshContext //刷新应用上下文,注册关闭应用钩子private void refreshContext(ConfigurableApplicationContext context) {refresh(context);if (this.registerShutdownHook) context.registerShutdownHook();}/*** 抽象父类ApplicationContext*/
public abstract class AbstractApplicationContext extends DefaultResourceLoaderimplements ConfigurableApplicationContext {Overridepublic void refresh() throws BeansException, IllegalStateException {synchronized (this.startupShutdownMonitor) {//清空缓存、清空监听器、判断必要属性是否被忽略、打印日志、初始化占位符、设置earlyApplicationEventsprepareRefresh();//获取并刷新beanFactoryConfigurableListableBeanFactory beanFactory obtainFreshBeanFactory();/*配置classLoader为当前context的classLoader设置BeanExpressionResolver, 解析EL表达式设置属性编辑器添加BeanPostProcessor配置自动装配手工注册environment相关bean*/prepareBeanFactory(beanFactory);/*注册basepackages注册annotatedClasses注册了request和session两个scopes注册几个Autowired依赖类 */postProcessBeanFactory(beanFactory);/*BeanFactoryPostProcessor接口用于增强BeanFactorySpring IoC 容器允许 BeanFactoryPostProcessor 在容器实例化任何 bean 之前读取bean 的定义并可以修改它。例如public static void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory, ListBeanFactoryPostProcessor beanFactoryPostProcessors) */invokeBeanFactoryPostProcessors(beanFactory);//beanFactory注册后置处理器对bean实例的增强registerBeanPostProcessors(beanFactory);//初始化messageSourceinitMessageSource();//初始化Application事件发布器initApplicationEventMulticaster();//初始化其他特殊的bean例如实例化了TomcatWebServeronRefresh();//注册监听器registerListeners();//完成beanFactory初始化finishBeanFactoryInitialization(beanFactory);//完成刷新,发布完成事件实例化了所有beanfinishRefresh();} }
}public abstract class AbstractApplicationContext extends DefaultResourceLoaderimplements ConfigurableApplicationContext {protected void prepareRefresh() {//记录开始时间,调整active状态this.startupDate System.currentTimeMillis();this.closed.set(false);this.active.set(true);//初始化占位符,例如:$,#,{}initPropertySources();//如果属性中缺少requiredProperties,那么抛出MissingRequiredPropertiesExceptiongetEnvironment().validateRequiredProperties();//清空监听器if (this.earlyApplicationListeners null) {this.earlyApplicationListeners new LinkedHashSet(this.applicationListeners);}else {this.applicationListeners.clear();this.applicationListeners.addAll(this.earlyApplicationListeners);}//初始化earlyApplicationEventsthis.earlyApplicationEvents new LinkedHashSet();}
}refreshContext.refresh.obtainFreshBeanFactory()
/*refreshBeanFactory()创建beanFactory、指定序列化Id、定制beanFactory、加载bean定义getBeanFactory()返回beanFactory实例
*/
protected ConfigurableListableBeanFactory obtainFreshBeanFactory() {//1.初始化beanFactory并执行加载和解析配置操作refreshBeanFactory();//返回beanFactory实例ConfigurableListableBeanFactory beanFactory getBeanFactory();if (logger.isDebugEnabled()) {logger.debug(Bean factory for getDisplayName() : beanFactory);}return beanFactory;}public abstract class AbstractRefreshableApplicationContext extends AbstractApplicationContext {... Overrideprotected final void refreshBeanFactory() throws BeansException {//判断是否存在beanFactoryif (hasBeanFactory()) {// 注销所有的单例destroyBeans();//重置beanFactorycloseBeanFactory();}try {//创建beanFactoryDefaultListableBeanFactory beanFactory createBeanFactory();//指定序列化id如果需要的话让这个BeanFactory从id反序列化到BeanFactory对象beanFactory.setSerializationId(getId());//定制BeanFactorycustomizeBeanFactory(beanFactory);//下载BeanDefinitions放到BeanDefinitionsMaploadBeanDefinitions(beanFactory);synchronized (this.beanFactoryMonitor) {this.beanFactory beanFactory;}}catch (IOException ex) {throw new ApplicationContextException(I/O error parsing bean definition source for getDisplayName(), ex);}}...
}refreshContext.refresh.finishBeanFactoryInitialization(beanFactory)
/* 根据loadBeanDefinitions加载的BeanDinition到BeanDefinitionMap再从BeanDefinitionMap拿出来BeanDefinitionMap创建Bean
*/
createBean(){//1. createBeanInstance通过反射机制获取Bean的构造方法然后创建Bean。当然如果构造方法需要参数就会到单例池中查找。//2. populateBean填充Bean属性//3. 初始化1. 初始化容器信息通过invokeAwareMethods唤醒各种Aware接口获取Bean在容器中的信息2. 初始化Bean成普通对象通过invokeInitMethods执行Bean的初始化方法这个方法可以通过实现InitialzingBean接口实现的afterPropertiesSet方法。3. AOP操作Bean成初始化之前和之后处理各种Bean的后置处理器即在invokeInitMethods之前和之后分别执行applyBeanPostProcessorsBeforeInitialization和applyBeanPostProcessorsAfterInitialization//4. 注册销毁实现了销毁接口DisposableBean在registerDisposableBean方法注册指定的Bean在销毁时可以直接执行destroy方法销毁Bean
}addSingleton(){将上面create出来的Bean放入单例池就可以获取和使用了
}非常重要的类
ResourceLoader
//默认的资源加载器
public class DefaultResourceLoader implements ResourceLoader {Nullableprivate ClassLoader classLoader;//自定义ProtocolResolver, 用于获取资源private final SetProtocolResolver protocolResolvers new LinkedHashSet(4);//private final MapClass?, MapResource, ? resourceCaches new ConcurrentHashMap(4);//实例化ClassLoaderpublic DefaultResourceLoader() {this.classLoader ClassUtils.getDefaultClassLoader();}//加载资源Overridepublic Resource getResource(String location) {Assert.notNull(location, Location must not be null);//自定义资源加载方式for (ProtocolResolver protocolResolver : this.protocolResolvers) {//调用ProtocolResolver的resolve方法Resource resource protocolResolver.resolve(location, this);if (resource ! null) {//如果获取到资源,立即返回return resource;}}if (location.startsWith(/)) {//先判断是否是根目录return getResourceByPath(location);}else if (location.startsWith(CLASSPATH_URL_PREFIX)) {//再判断是否是classpath下的资源return new ClassPathResource(location.substring(CLASSPATH_URL_PREFIX.length()), getClassLoader());}else {try {//先当做一个URL处理URL url new URL(location);//先判断是否是一个file//不是file的话,再从URL中获取return (ResourceUtils.isFileURL(url) ? new FileUrlResource(url) : new UrlResource(url));}catch (MalformedURLException ex) {//获取不到资源的话//当做resource处理return getResourceByPath(location);}}}
}总结 1. 服务构建 设置primarySourcesYanggxApplication.class设置webTypeSERVLET从Spring.factories获取初始化器从Spring.factories获取监听器ApplicationListener设置启动类YanggxApplication.class 2. 环境准备 发布Spring启动事件listeners.starting封装args参数 new DefaultApplicationArguments(args);配置环境并让环境生效prepareEnvironment() configureIgnoreBeanInfo()打印Banner图printBanner(environment) 3. 容器创建 创建容器createApplicationContext()设置容器prepareContext()刷新容器refreshContext()这里也是填充容器重点是 invokeBeanFactoryPostProcessors(beanFactory);和onRefresh执行Runners 4. 填充容器就是容器创建的refreshContext
