springboot 基于Tomcat容器的自启动流程分析

 public class TestServiceImpl { public void testImpl() { System.out.println("我是通过importSelector导入进来的service"); } } public class TestService implements ImportSelector { @Override public String[] selectImports(AnnotationMetadata annotationMetadata) { return new String[]{"com.ycdhz.service.TestServiceImpl"}; } } @Configuration @Import(value = {TestService.class}) public class TestConfig { } public class TestController { @Autowired private TestServiceImpl testServiceImpl; @RequestMapping("testImpl") public String testTuling() { testServiceImpl.testImpl(); return "Ok"; } }

 public class TestService { public TestService() { System.out.println("我是通过ImportBeanDefinitionRegistrar导入进来的组件"); } } public class TestImportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar { @Override public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) { //定义一个BeanDefinition RootBeanDefinition beanDefinition = new RootBeanDefinition(TestService.class); //把自定义的bean定义导入到容器中 registry.registerBeanDefinition("testService",beanDefinition); } } @Configuration @Import(TestImportBeanDefinitionRegistrar.class) public class TestConfig { }

 public class TomcatWebServerFactoryCustomizer implements WebServerFactoryCustomizer, Ordered { @Override public void customize(ConfigurableTomcatWebServerFactory factory) { ServerProperties properties = this.serverProperties; ServerProperties.Tomcat tomcatProperties = properties.getTomcat(); PropertyMapper propertyMapper = PropertyMapper.get(); propertyMapper.from(tomcatProperties::getBasedir).whenNonNull() .to(factory::setBaseDirectory); propertyMapper.from(tomcatProperties::getBackgroundProcessorDelay).whenNonNull() .as(Duration::getSeconds).as(Long::intValue) .to(factory::setBackgroundProcessorDelay); customizeRemoteIpValve(factory); propertyMapper.from(tomcatProperties::getMaxThreads).when(this::isPositive) .to((maxThreads) -> customizeMaxThreads(factory, tomcatProperties.getMaxThreads())); propertyMapper.from(tomcatProperties::getMinSpareThreads).when(this::isPositive) .to((minSpareThreads) -> customizeMinThreads(factory, minSpareThreads)); propertyMapper.from(() -> determineMaxHttpHeaderSize()).when(this::isPositive) .to((maxHttpHeaderSize) -> customizeMaxHttpHeaderSize(factory, maxHttpHeaderSize)); propertyMapper.from(tomcatProperties::getMaxHttpPostSize) .when((maxHttpPostSize) -> maxHttpPostSize != 0) .to((maxHttpPostSize) -> customizeMaxHttpPostSize(factory, maxHttpPostSize)); propertyMapper.from(tomcatProperties::getAccesslog) .when(ServerProperties.Tomcat.Accesslog::isEnabled) .to((enabled) -> customizeAccessLog(factory)); propertyMapper.from(tomcatProperties::getUriEncoding).whenNonNull() .to(factory::setUriEncoding); propertyMapper.from(properties::getConnectionTimeout).whenNonNull() .to((connectionTimeout) -> customizeConnectionTimeout(factory, connectionTimeout)); propertyMapper.from(tomcatProperties::getMaxConnections).when(this::isPositive) .to((maxConnections) -> customizeMaxConnections(factory, maxConnections)); propertyMapper.from(tomcatProperties::getAcceptCount).when(this::isPositive) .to((acceptCount) -> customizeAcceptCount(factory, acceptCount)); customizeStaticResources(factory); customizeErrorReportValve(properties.getError(), factory); } }

 public class ServletWebServerFactoryCustomizer implements WebServerFactoryCustomizer, Ordered { private final ServerProperties serverProperties; public ServletWebServerFactoryCustomizer(ServerProperties serverProperties) { this.serverProperties = serverProperties; } @Override public int getOrder() { return 0; } @Override public void customize(ConfigurableServletWebServerFactory factory) { PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull(); map.from(this.serverProperties::getPort).to(factory::setPort); map.from(this.serverProperties::getAddress).to(factory::setAddress); map.from(this.serverProperties.getServlet()::getContextPath) .to(factory::setContextPath); map.from(this.serverProperties.getServlet()::getApplicationDisplayName) .to(factory::setDisplayName); map.from(this.serverProperties.getServlet()::getSession).to(factory::setSession); map.from(this.serverProperties::getSsl).to(factory::setSsl); map.from(this.serverProperties.getServlet()::getJsp).to(factory::setJsp); map.from(this.serverProperties::getCompression).to(factory::setCompression); map.from(this.serverProperties::getHttp2).to(factory::setHttp2); map.from(this.serverProperties::getServerHeader).to(factory::setServerHeader); map.from(this.serverProperties.getServlet()::getContextParameters) .to(factory::setInitParameters); } }

 public class TomcatServletWebServerFactoryCustomizer implements WebServerFactoryCustomizer, Ordered { private final ServerProperties serverProperties; public TomcatServletWebServerFactoryCustomizer(ServerProperties serverProperties) { this.serverProperties = serverProperties; } @Override public void customize(TomcatServletWebServerFactory factory) { ServerProperties.Tomcat tomcatProperties = this.serverProperties.getTomcat(); if (!ObjectUtils.isEmpty(tomcatProperties.getAdditionalTldSkipPatterns())) { factory.getTldSkipPatterns() .addAll(tomcatProperties.getAdditionalTldSkipPatterns()); } if (tomcatProperties.getRedirectContextRoot() != null) { customizeRedirectContextRoot(factory, tomcatProperties.getRedirectContextRoot()); } if (tomcatProperties.getUseRelativeRedirects() != null) { customizeUseRelativeRedirects(factory, tomcatProperties.getUseRelativeRedirects()); } } }

 @Override public WebServer getWebServer(ServletContextInitializer... initializers) { Tomcat tomcat = new Tomcat(); File baseDir = (this.baseDirectory != null) ? this.baseDirectory : createTempDir("tomcat"); tomcat.setBaseDir(baseDir.getAbsolutePath()); Connector connector = new Connector(this.protocol); tomcat.getService().addConnector(connector); customizeConnector(connector); tomcat.setConnector(connector); //设置是否自动启动 tomcat.getHost().setAutoDeploy(false); //创建Tomcat引擎 configureEngine(tomcat.getEngine()); for (Connector additionalConnector : this.additionalTomcatConnectors) { tomcat.getService().addConnector(additionalConnector); } //刷新上下文 prepareContext(tomcat.getHost(), initializers); //准备启动 return getTomcatWebServer(tomcat); }

 private void initialize() throws WebServerException { TomcatWebServer.logger .info("Tomcat initialized with port(s): " + getPortsDescription(false)); synchronized (this.monitor) { try { addInstanceIdToEngineName(); Context context = findContext(); context.addLifecycleListener((event) -> { if (context.equals(event.getSource()) && Lifecycle.START_EVENT.equals(event.getType())) { // Remove service connectors so that protocol binding doesn't // happen when the service is started. removeServiceConnectors(); } }); // Start the server to trigger initialization listeners this.tomcat.start(); // We can re-throw failure exception directly in the main thread rethrowDeferredStartupExceptions(); try { ContextBindings.bindClassLoader(context, context.getNamingToken(), getClass().getClassLoader()); } catch (NamingException ex) { // Naming is not enabled. Continue } // Unlike Jetty, all Tomcat threads are daemon threads. We create a // blocking non-daemon to stop immediate shutdown startDaemonAwaitThread(); } catch (Exception ex) { stopSilently(); throw new WebServerException("Unable to start embedded Tomcat", ex); } } }

 org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#doCreateBean 　　org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory#initializeBean

 protected Object doCreateBean(final String beanName, final RootBeanDefinition mbd, final @Nullable Object[] args) throws BeanCreationException { // Instantiate the bean. BeanWrapper instanceWrapper = null; if (mbd.isSingleton()) { instanceWrapper = this.factoryBeanInstanceCache.remove(beanName); } if (instanceWrapper == null) { //构造方法 instanceWrapper = createBeanInstance(beanName, mbd, args); } final Object bean = instanceWrapper.getWrappedInstance(); Class beanType = instanceWrapper.getWrappedClass(); if (beanType != NullBean.class) { mbd.resolvedTargetType = beanType; } // Initialize the bean instance. ...... return exposedObject; } protected Object initializeBean(final String beanName, final Object bean, @Nullable RootBeanDefinition mbd) { if (System.getSecurityManager() != null) { AccessController.doPrivileged((PrivilegedAction