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springboot源码流程解析

2021-10-30 09:59:17   32  举报

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springboot源码流程解析

springboot

springboot源码流程

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大纲/内容

1.启动流程

SpringApplication.run(HibikiApplication.class, args);
--run(new Class<?>[] { primarySource }, args)
----new SpringApplication(primarySources).run(args)

this(resourceLoader：null, primarySources);

this.resourceLoader = resourceLoader;

this.primarySources = new LinkedHashSet<>(Arrays.asList(primarySources));

this.webApplicationType = WebApplicationType.deduceFromClasspath();

REACTIVE

NONE

SERVLET

setInitializers((Collection) getSpringFactoriesInstances(ApplicationContextInitializer.class));

getSpringFactoriesInstances(ApplicationContextInitializer.class，new Class<?>[] {})

getClassLoader()

Set<String> names = new LinkedHashSet<>(SpringFactoriesLoader.loadFactoryNames(type, classLoader))
>>loadSpringFactories(classLoader).getOrDefault(factoryTypeName, Collections.emptyList())

(List)loadSpringFactories(classLoader)

getOrDefault(factoryTypeName, Collections.emptyList()

List<T> instances = createSpringFactoriesInstances(type, parameterTypes, classLoader, args, names)

setInitializers
--this.initializers = new ArrayList<>(initializers)

setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
--this.listeners = new ArrayList<>(listeners);

this.mainApplicationClass = deduceMainApplicationClass();

#run(args)

ConfigurableApplicationContext context = null

Collection<SpringBootExceptionReporter> exceptionReporters = new ArrayList<>()

SpringApplicationRunListeners listeners = getRunListeners(args);

Class<?>[] types = new Class<?>[] { SpringApplication.class, String[].class };

return new SpringApplicationRunListeners(logger,
getSpringFactoriesInstances(SpringApplicationRunListener.class, types, this, args))

listeners.starting()

this.initialMulticaster.multicastEvent(new ApplicationStartingEvent(this.application, this.args));

RestartApplicationListener#onApplicationStartingEvent

ApplicationArguments applicationArguments = new DefaultApplicationArguments(args)

ConfigurableEnvironment environment = prepareEnvironment(listeners, applicationArguments);

configureIgnoreBeanInfo(environment);

Banner printedBanner = printBanner(environment);

context = createApplicationContext();

若没有显示指定容器的类型，则根据this.webApplicationType创建class

若为SERVLET，创建AnnotationConfigServletWebServerApplicationContext，反射实例化

exceptionReporters = getSpringFactoriesInstances(SpringBootExceptionReporter.class,

new Class[] { ConfigurableApplicationContext.class }, context);

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

context.setEnvironment(environment)

postProcessApplicationContext(context);

applyInitializers(context);

循环依次initializer.initialize(context)

listeners.contextPrepared(context);

beanFactory.registerSingleton("springApplicationArguments", applicationArguments);

若this.lazyInitialization：默认false，可在yaml配置main:lazy-initialization:true
context.addBeanFactoryPostProcessor(new LazyInitializationBeanFactoryPostProcessor())

Set<Object> sources = getAllSources();

load(context, sources.toArray(new Object[0]))

listeners.contextLoaded(context);

refreshContext(context);

refresh((ApplicationContext) context);

大部分与普通springioc容器流程相同，详情见springioc流程分析

不同点

#invokeBeanFactoryPostProcessors

ServletWebServerApplicationContext#Onfresh

this.themeSource = UiApplicationContextUtils.initThemeSource(this);

createWebServer()

ServletWebServerFactory factory = getWebServerFactory();

String[] beanNames = getBeanFactory().getBeanNamesForType(ServletWebServerFactory.class)
>>return getBeanFactory().getBean(beanNames[0], ServletWebServerFactory.class)

this.webServer = factory.getWebServer(getSelfInitializer());

getSelfInitializer()
--return this::selfInitialize: 传入方法引用，匿名函数，在之后webServer初始化时调用
>>>>selfInitialize(ServletContext servletContext)

prepareWebApplicationContext(servletContext);

Object rootContext = servletContext.getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);

servletContext.setAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE, this);

setServletContext(servletContext);

registerApplicationScope(servletContext);

ServletContextScope appScope = new ServletContextScope(servletContext);

getBeanFactory().registerScope(“application”, appScope);

servletContext.setAttribute(ServletContextScope.class.getName(), appScope);

WebApplicationContextUtils.registerEnvironmentBeans(getBeanFactory(), servletContext);
--registerEnvironmentBeans(bf, sc, (ServletConfig)null);
----bf.registerSingleton("servletContext", servletContext);
----bf.registerSingleton("contextParameters", Collections.unmodifiableMap(attributeMap));
----bf.registerSingleton("contextAttributes", Collections.unmodifiableMap(attributeMap));

for (ServletContextInitializer beans : getServletContextInitializerBeans())
>>beans.onStartup(servletContext);

getServletContextInitializerBeans()
--return new ServletContextInitializerBeans(getBeanFactory());
----addServletContextInitializerBeans(beanFactory);
----addAdaptableBeans(beanFactory);

getWebServer(ServletContextInitializer... initializers)

Tomcat tomcat = new Tomcat();

prepareContext(tomcat.getHost(), initializers);

TomcatEmbeddedContext context = new TomcatEmbeddedContext();

addDefaultServlet(context);

configureContext(context, initializersToUse);

TomcatStarter starter = new TomcatStarter(initializers);

for (TomcatContextCustomizer customizer : this.tomcatContextCustomizers) {
customizer.customize(context);
}

postProcessContext(context);

return getTomcatWebServer(tomcat);
--return new TomcatWebServer(tomcat, getPort() >= 0, getShutdown());

getBeanFactory().registerSingleton("webServerGracefulShutdown",

new WebServerGracefulShutdownLifecycle(this.webServer));

getBeanFactory().registerSingleton("webServerStartStop",

new WebServerStartStopLifecycle(this, this.webServer));

GenericWebApplicationContext#initPropertySources();
--ConfigurableEnvironment env = this.getEnvironment();
--env.initPropertySources(this.servletContext, (ServletConfig)null);
----WebApplicationContextUtils.initServletPropertySources(this.getPropertySources(), servletContext, servletConfig);

sources.replace("servletContextInitParams", new ServletContextPropertySource("servletContextInitParams", servletContext));

sources.replace("servletConfigInitParams", new ServletConfigPropertySource("servletConfigInitParams", servletConfig));

#registerListeners

详情见springioc流程分析

#finishRefresh

getLifecycleProcessor().onRefresh();

DefaultLifecycleProcessor#startBeans(true);

Map<String, Lifecycle> lifecycleBeans = getLifecycleBeans();

webServerStartStop#start

this.webServer.start();

this.running = true;

this.applicationContext.publishEvent
(new ServletWebServerInitializedEvent(this.webServer, this.applicationContext));

webServerGracefulShutdown

根据各个bean不同的应用阶段分组

调用LifecycleGroup中的所有Lifecycle的start方法

this.running = true;

this.webServer.start()

context.registerShutdownHook();

afterRefresh(context, applicationArguments);

listeners.started(context);

callRunners(context, applicationArguments);

List<Object> runners = new ArrayList<>();

runners.addAll(context.getBeansOfType(ApplicationRunner.class).values());

runners.addAll(context.getBeansOfType(CommandLineRunner.class).values());

循环callRunner((CommandLineRunner) runner, args);

listeners.running(context);

2.@SpringBootApplication

@SpringBootConfiguration

@Configuration

@Component

说明Spring的配置类也是Spring的一个组件

@ComponentScan(excludeFilters = {x,x})

AutoConfigurationExcludeFilter

TypeExcludeFilter

@EnableAutoConfiguration

@AutoConfigurationPackage

@Import(AutoConfigurationPackages.Registrar.class)
自动注册包---主配置类所在的包:com.kuang.demo包

#registerBeanDefinitions

@Import(AutoConfigurationImportSelector.class)自动导入包的核心

#selectImports(AnnotationMetadata annotationMetadata)

#isEnabled(AnnotationMetadata metadata)

#getAutoConfigurationEntry(AnnotationMetadata annotationMetadata)

#getCandidateConfigurations(annotationMetadata, attributes)

导入的类：自动导入选择器AutoConfigurationImportSelector

类里有个方法：getAutoConfigurationEntry
作用：获得自动配置实体

该方法里调用了方法：getCandidateConfigurations
目的：获取候选的配置

该方法调用了
List<String> configurations = SpringFactoriesLoader.loadFactoryNames(this.getSpringFactoriesLoaderFactoryClass(), this.getBeanClassLoader())
关注参数最后返回的就是自动配置的类：就是META-INF/factories下的自动配置类名的集合

getSpringFactoriesLoaderFactoryClass()

return EnableAutoConfiguration.class;

获取标注了EnableAutoConfiguration这个注解的类：
包括主启动类public class Application

应用

自定义运行监听器

implements SpringApplicationRunListener
extends EventPublishingRunListener

写入factories中

插手ServletContext初始化工作

implements ServletContextInitializer

自定义配置嵌入式Servlet容器

implements WebServerFactoryCustomizer<TomcatServletWebServerFactory>

mvc自定义配置

implements WebMvcConfigurer

自定义事件