Servlet容器的自動配置是通過ServletWebServerFactoryAutoConfiguration 自動配置類來實現的,先不看里面方法,從類注解看起。
@Configuration( proxyBeanMethods = false ) //表示這個一個配置類 @AutoConfigureOrder(-2147483648) @ConditionalOnClass({ServletRequest.class}) //只有包含ServletRequest這個類的時候此配置類才會生效 @ConditionalOnWebApplication( type = Type.SERVLET )//當前是web環境 @EnableConfigurationProperties({ServerProperties.class})//啟動指定類的ConfigurationProperties功能;將配置文件中對應的值和ServerProperties綁定起來;並把ServerProperties加入到ioc容器中 @Import({ServletWebServerFactoryAutoConfiguration.BeanPostProcessorsRegistrar.class, EmbeddedTomcat.class, EmbeddedJetty.class, EmbeddedUndertow.class})//導入這四個Bean到容器中,下面詳細講解 public class ServletWebServerFactoryAutoConfiguration { }
首先略過BeanPostProcessorsRegistrar,來看EmbeddeTomcat.class
@ConditionalOnClass({Servlet.class, Tomcat.class, UpgradeProtocol.class})//只有包含Tomcat類時才會生效,不同的Servlet容器引入jar包不同,Jetty與UnderTow的配置也是通過這個區分 @ConditionalOnMissingBean( value = {ServletWebServerFactory.class}, search = SearchStrategy.CURRENT )//當系統中沒有ServletWebServerFactory時,才會使用下面創建的、//ServletWebServerFactory,通過這其實可以看出,我們可以自定義ServletWebServerFactory來實現自己的配置
static class EmbeddedTomcat {
EmbeddedTomcat() {
}
@Bean
TomcatServletWebServerFactory tomcatServletWebServerFactory(ObjectProvider<TomcatConnectorCustomizer> connectorCustomizers, ObjectProvider<TomcatContextCustomizer> contextCustomizers, ObjectProvider<TomcatProtocolHandlerCustomizer<?>> protocolHandlerCustomizers) {
TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();
factory.getTomcatConnectorCustomizers().addAll((Collection)connectorCustomizers.orderedStream().collect(Collectors.toList()));
factory.getTomcatContextCustomizers().addAll((Collection)contextCustomizers.orderedStream().collect(Collectors.toList()));
factory.getTomcatProtocolHandlerCustomizers().addAll((Collection)protocolHandlerCustomizers.orderedStream().collect(Collectors.toList()));
return factory;
}
}
其實只干了一件事,就是將TomcatServletWebServerFactory 注冊到容器當中,點開TomcatServletWebServerFactory 看一下。
里面關鍵是這個方法
public WebServer getWebServer(ServletContextInitializer... initializers) { if (this.disableMBeanRegistry) { Registry.disableRegistry(); } Tomcat tomcat = new Tomcat(); File baseDir = this.baseDirectory != null ? this.baseDirectory : this.createTempDir("tomcat"); tomcat.setBaseDir(baseDir.getAbsolutePath()); Connector connector = new Connector(this.protocol); connector.setThrowOnFailure(true); tomcat.getService().addConnector(connector); this.customizeConnector(connector); tomcat.setConnector(connector); tomcat.getHost().setAutoDeploy(false); this.configureEngine(tomcat.getEngine()); Iterator var5 = this.additionalTomcatConnectors.iterator(); while(var5.hasNext()) { Connector additionalConnector = (Connector)var5.next(); tomcat.getService().addConnector(additionalConnector); } this.prepareContext(tomcat.getHost(), initializers); return this.getTomcatWebServer(tomcat); }
其實用用java生成了一個tomcat,然后繼續點擊getTomcatWebServer,TomcatServletWebServerFactory 會新創建類一個TomcatWebServer
protected TomcatWebServer getTomcatWebServer(Tomcat tomcat) { return new TomcatWebServer(tomcat, this.getPort() >= 0, this.getShutdown()); }
在不修改端口號的情況下TomcatServletWebServerFactory 默認配置端口為8080
public int getPort() { return this.port; } private int port = 8080;
public TomcatWebServer(Tomcat tomcat, boolean autoStart, Shutdown shutdown) { this.monitor = new Object(); this.serviceConnectors = new HashMap(); Assert.notNull(tomcat, "Tomcat Server must not be null"); this.tomcat = tomcat; this.autoStart = autoStart; this.gracefulShutdown = shutdown == Shutdown.GRACEFUL ? new GracefulShutdown(tomcat) : null; this.initialize(); //執行初始化 } private void initialize() throws WebServerException { logger.info("Tomcat initialized with port(s): " + this.getPortsDescription(false)); synchronized(this.monitor) { try { this.addInstanceIdToEngineName(); Context context = this.findContext(); context.addLifecycleListener((event) -> { if (context.equals(event.getSource()) && "start".equals(event.getType())) { this.removeServiceConnectors(); } }); this.tomcat.start();//tomcat被啟動 this.rethrowDeferredStartupExceptions(); try { ContextBindings.bindClassLoader(context, context.getNamingToken(), this.getClass().getClassLoader()); } catch (NamingException var5) { } this.startDaemonAwaitThread(); } catch (Exception var6) { this.stopSilently(); this.destroySilently(); throw new WebServerException("Unable to start embedded Tomcat", var6); } } }
同理EmbeddedJetty與EmbeddedUndertow也是如此。
那么我們如何自定義相關配置,又如何生效呢?
有兩種方式:
1、通過application.yml里面配置。如何生效?
回到最上面,引入ServerProperties。打開看一下
@ConfigurationProperties( prefix = "server", ignoreUnknownFields = true )//是與配置文件中的server下的內容綁定,我們能配置的內容也就是下面下面這些 public class ServerProperties { private Integer port; private InetAddress address; @NestedConfigurationProperty private final ErrorProperties error = new ErrorProperties(); private ServerProperties.ForwardHeadersStrategy forwardHeadersStrategy; private String serverHeader; private DataSize maxHttpHeaderSize = DataSize.ofKilobytes(8L); private Shutdown shutdown; @NestedConfigurationProperty private Ssl ssl; @NestedConfigurationProperty private final Compression compression; @NestedConfigurationProperty private final Http2 http2; private final ServerProperties.Servlet servlet; private final ServerProperties.Tomcat tomcat; private final ServerProperties.Jetty jetty; private final ServerProperties.Netty netty; private final ServerProperties.Undertow undertow; }
配置內容與bean綁定以后如何生效的呢?下面就用到了自動配置類里面的代碼
@Bean public ServletWebServerFactoryCustomizer servletWebServerFactoryCustomizer(ServerProperties serverProperties) { return new ServletWebServerFactoryCustomizer(serverProperties); } @Bean @ConditionalOnClass( name = {"org.apache.catalina.startup.Tomcat"} ) public TomcatServletWebServerFactoryCustomizer tomcatServletWebServerFactoryCustomizer(ServerProperties serverProperties) { return new TomcatServletWebServerFactoryCustomizer(serverProperties); }
注冊ServletWebServerFactoryCustomizer與TomcatServletWebServerFactoryCustomizer兩個對象到Spring容器中時傳入。
public class ServletWebServerFactoryCustomizer implements WebServerFactoryCustomizer<ConfigurableServletWebServerFactory>, Ordered { private final ServerProperties serverProperties; public ServletWebServerFactoryCustomizer(ServerProperties serverProperties) { this.serverProperties = serverProperties; } public int getOrder() { return 0; } public void customize(ConfigurableServletWebServerFactory factory) { PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull(); ServerProperties var10001 = this.serverProperties; var10001.getClass(); map.from(var10001::getPort).to(factory::setPort); var10001 = this.serverProperties; var10001.getClass(); map.from(var10001::getAddress).to(factory::setAddress); Servlet var3 = this.serverProperties.getServlet(); var3.getClass(); map.from(var3::getContextPath).to(factory::setContextPath); var3 = this.serverProperties.getServlet(); var3.getClass(); map.from(var3::getApplicationDisplayName).to(factory::setDisplayName); var3 = this.serverProperties.getServlet(); var3.getClass(); map.from(var3::isRegisterDefaultServlet).to(factory::setRegisterDefaultServlet); var3 = this.serverProperties.getServlet(); var3.getClass(); map.from(var3::getSession).to(factory::setSession); var10001 = this.serverProperties; var10001.getClass(); map.from(var10001::getSsl).to(factory::setSsl); var3 = this.serverProperties.getServlet(); var3.getClass(); map.from(var3::getJsp).to(factory::setJsp); var10001 = this.serverProperties; var10001.getClass(); map.from(var10001::getCompression).to(factory::setCompression); var10001 = this.serverProperties; var10001.getClass(); map.from(var10001::getHttp2).to(factory::setHttp2); var10001 = this.serverProperties; var10001.getClass(); map.from(var10001::getServerHeader).to(factory::setServerHeader); var3 = this.serverProperties.getServlet(); var3.getClass(); map.from(var3::getContextParameters).to(factory::setInitParameters); map.from(this.serverProperties.getShutdown()).to(factory::setShutdown); } }
public class TomcatServletWebServerFactoryCustomizer implements WebServerFactoryCustomizer<TomcatServletWebServerFactory>, Ordered { private final ServerProperties serverProperties; public TomcatServletWebServerFactoryCustomizer(ServerProperties serverProperties) { this.serverProperties = serverProperties; } public int getOrder() { return 0; } public void customize(TomcatServletWebServerFactory factory) { Tomcat tomcatProperties = this.serverProperties.getTomcat(); if (!ObjectUtils.isEmpty(tomcatProperties.getAdditionalTldSkipPatterns())) { factory.getTldSkipPatterns().addAll(tomcatProperties.getAdditionalTldSkipPatterns()); } if (tomcatProperties.getRedirectContextRoot() != null) { this.customizeRedirectContextRoot(factory, tomcatProperties.getRedirectContextRoot()); } this.customizeUseRelativeRedirects(factory, tomcatProperties.isUseRelativeRedirects()); factory.setDisableMBeanRegistry(!tomcatProperties.getMbeanregistry().isEnabled()); } private void customizeRedirectContextRoot(ConfigurableTomcatWebServerFactory factory, boolean redirectContextRoot) { factory.addContextCustomizers(new TomcatContextCustomizer[]{(context) -> { context.setMapperContextRootRedirectEnabled(redirectContextRoot); }}); } private void customizeUseRelativeRedirects(ConfigurableTomcatWebServerFactory factory, boolean useRelativeRedirects) { factory.addContextCustomizers(new TomcatContextCustomizer[]{(context) -> { context.setUseRelativeRedirects(useRelativeRedirects); }}); } }
打開兩個類可以看到在customize方法里面會被應用,去配置對應的容器工廠類。聯系上面,工廠類是用來注冊容器實例的,那么這個customize這個配置一定會在此之前被調用,什么時候呢?這時候來看開頭忽略的Import
BeanPostProcessorsRegistrar
public static class BeanPostProcessorsRegistrar implements ImportBeanDefinitionRegistrar, BeanFactoryAware { private ConfigurableListableBeanFactory beanFactory; public BeanPostProcessorsRegistrar() { } public void setBeanFactory(BeanFactory beanFactory) throws BeansException { if (beanFactory instanceof ConfigurableListableBeanFactory) { this.beanFactory = (ConfigurableListableBeanFactory)beanFactory; } } public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry) { if (this.beanFactory != null) { this.registerSyntheticBeanIfMissing(registry, "webServerFactoryCustomizerBeanPostProcessor", WebServerFactoryCustomizerBeanPostProcessor.class); this.registerSyntheticBeanIfMissing(registry, "errorPageRegistrarBeanPostProcessor", ErrorPageRegistrarBeanPostProcessor.class); } } private void registerSyntheticBeanIfMissing(BeanDefinitionRegistry registry, String name, Class<?> beanClass) { if (ObjectUtils.isEmpty(this.beanFactory.getBeanNamesForType(beanClass, true, false))) { RootBeanDefinition beanDefinition = new RootBeanDefinition(beanClass); beanDefinition.setSynthetic(true); registry.registerBeanDefinition(name, beanDefinition); } } }
this.registerSyntheticBeanIfMissing(registry, "webServerFactoryCustomizerBeanPostProcessor", WebServerFactoryCustomizerBeanPostProcessor.class);
這一行是關鍵,打開
public class WebServerFactoryCustomizerBeanPostProcessor implements BeanPostProcessor, BeanFactoryAware { private ListableBeanFactory beanFactory; private List<WebServerFactoryCustomizer<?>> customizers; public WebServerFactoryCustomizerBeanPostProcessor() { } public void setBeanFactory(BeanFactory beanFactory) { Assert.isInstanceOf(ListableBeanFactory.class, beanFactory, "WebServerCustomizerBeanPostProcessor can only be used with a ListableBeanFactory"); this.beanFactory = (ListableBeanFactory)beanFactory; } public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { if (bean instanceof WebServerFactory) { this.postProcessBeforeInitialization((WebServerFactory)bean); } return bean; } public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException { return bean; } //在Servlet初始化之前執行 private void postProcessBeforeInitialization(WebServerFactory webServerFactory) { ((Callbacks)LambdaSafe.callbacks(WebServerFactoryCustomizer.class, //取出所有Customizers this.getCustomizers(), webServerFactory, new Object[0]).withLogger(WebServerFactoryCustomizerBeanPostProcessor.class)).invoke((customizer) -> {
//對Spring容器中的WebServerFactory執行customize方法。 customizer.customize(webServerFactory); }); } private Collection<WebServerFactoryCustomizer<?>> getCustomizers() { if (this.customizers == null) { this.customizers = new ArrayList(this.getWebServerFactoryCustomizerBeans()); this.customizers.sort(AnnotationAwareOrderComparator.INSTANCE); this.customizers = Collections.unmodifiableList(this.customizers); } return this.customizers; } private Collection<WebServerFactoryCustomizer<?>> getWebServerFactoryCustomizerBeans() { return this.beanFactory.getBeansOfType(WebServerFactoryCustomizer.class, false, false).values(); //取出Spring容器中Customizer的類型是繼承自WebServerFactoryCustomizer } }
通過
customizer.customize(webServerFactory);
我們在application里面配置的內容就應用到了其中。
另一種是就是自定義的WebServerFactory,可以
@Configuration public class WebConfigurer { @Bean public ConfigurableServletWebServerFactory configurableServletWebServerFactory(){ TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory(); factory.setPort(8585); return factory; } }
將我們自定義的ConfigurableServletWebServerFactory注入到了Spring容器中
@ConditionalOnMissingBean( value = {ServletWebServerFactory.class},
這樣自定義的Factory就不會生效了,而自定義的Factory注入到Spring容器中以后會被
customizer.customize(webServerFactory);
應用,這么看執行過程,如果同時配置了Factory Bean與yml,應該Factory Bean里面配置的會被yml里面的同等配置替代,所以yml配置優先。
有一個疑問,我只找到了
@Bean public ServletWebServerFactoryCustomizer servletWebServerFactoryCustomizer(ServerProperties serverProperties) { return new ServletWebServerFactoryCustomizer(serverProperties); } @Bean @ConditionalOnClass( name = {"org.apache.catalina.startup.Tomcat"} ) public TomcatServletWebServerFactoryCustomizer tomcatServletWebServerFactoryCustomizer(ServerProperties serverProperties) { return new TomcatServletWebServerFactoryCustomizer(serverProperties); }
並沒有找到像
Jetty和Undertow的Customizer的注冊Bean