springboot-内置tomcat

跟踪springboot自启动tomcat

    工作需要修改内置tomcat连接参数，将自己分析前后分享。
​   springboot 内置tomcat，tomcat为自动开启的配置，进入@SpringBootApplication注解。

//@SpringBootApplication注解源码
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@SpringBootConfiguration
@EnableAutoConfiguration    //开启自启动程序
@ComponentScan(excludeFilters = {
      @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),
      @Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) })
public @interface SpringBootApplication {

//@EnableAutoConfiguration 注解源码
@SuppressWarnings("deprecation")
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@AutoConfigurationPackage
@Import(EnableAutoConfigurationImportSelector.class) //加载需要自启动的配置文件
public @interface EnableAutoConfiguration {

​   springboot原理，就是使用SpingFactoriesLoader.loadFactoryNames 扫描具有META-INFO/spring.factories文件的jar包 。

​   加载容器的配置文件 EmbeddedServletContainerAutoConfiguration,在配置文件中，内置tomcat（满足tomcat容器条件的bean存在），只要满足Jetty、Undertow的条件，可以切换为其他容器。

//EmbeddedServletContainerAutoConfiguration 源码
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE)
@Configuration
@ConditionalOnWebApplication
@Import(BeanPostProcessorsRegistrar.class)
public class EmbeddedServletContainerAutoConfiguration {

   /**
    * Nested configuration if Tomcat is being used.
    */
   @Configuration       //tomcat启动条件（springboot内置存在）
   @ConditionalOnClass({ Servlet.class, Tomcat.class })  
   @ConditionalOnMissingBean(value = EmbeddedServletContainerFactory.class, search = SearchStrategy.CURRENT)
   public static class EmbeddedTomcat {

      @Bean
      public TomcatEmbeddedServletContainerFactory tomcatEmbeddedServletContainerFactory() {
         return new TomcatEmbeddedServletContainerFactory();
      }

   }

   /**
    * Nested configuration if Jetty is being used.
    */
   @Configuration     //jetty启动条件 ：导入相应的pom文件即可
   @ConditionalOnClass({ Servlet.class, Server.class, Loader.class,
         WebAppContext.class })   
   @ConditionalOnMissingBean(value = EmbeddedServletContainerFactory.class, search = SearchStrategy.CURRENT)
   public static class EmbeddedJetty {

      @Bean
      public JettyEmbeddedServletContainerFactory jettyEmbeddedServletContainerFactory() {
         return new JettyEmbeddedServletContainerFactory();
      }

   }

   /**
    * Nested configuration if Undertow is being used.
    */
   @Configuration     //Undertow 启动条件
   @ConditionalOnClass({ Servlet.class, Undertow.class, SslClientAuthMode.class })
   @ConditionalOnMissingBean(value = EmbeddedServletContainerFactory.class, search = SearchStrategy.CURRENT)
   public static class EmbeddedUndertow {

      @Bean
      public UndertowEmbeddedServletContainerFactory undertowEmbeddedServletContainerFactory() {
         return new UndertowEmbeddedServletContainerFactory();
      }

   }

​   以tomcat为例，继续看如何加载并配置servlet容器       TomcatEmbeddedServletContainerFactory 获取容器

@Override
public EmbeddedServletContainer getEmbeddedServletContainer(
      ServletContextInitializer... initializers) {
   Tomcat tomcat = new Tomcat();
   File baseDir = (this.baseDirectory != null ? this.baseDirectory
         : createTempDir("tomcat"));
   tomcat.setBaseDir(baseDir.getAbsolutePath());
  //通过nio1连接 org.apache.coyote.http11.Http11NioProtocol
   Connector connector = new Connector(this.protocol);  
   tomcat.getService().addConnector(connector);
   customizeConnector(connector);  //connector 个性化配置  //模板设计模式
   tomcat.setConnector(connector);
   tomcat.getHost().setAutoDeploy(false);
   configureEngine(tomcat.getEngine());
   for (Connector additionalConnector : this.additionalTomcatConnectors) {
      tomcat.getService().addConnector(additionalConnector);
   }
   prepareContext(tomcat.getHost(), initializers);
   return getTomcatEmbeddedServletContainer(tomcat);
}

​   继续跟踪查看customizeConnector(connector);   

​   查看此方法源码 所以有两种方式可以实现个性化的connector

​   1.继承 TomcatEmbeddedServletContainerFactory 重写此方法，加入个性化配置

​   2.实现TomcatConnectorCustomizer 接口，将实现类加入到TomcatEmbeddedServletContainerFactory 

for (TomcatConnectorCustomizer customizer : this.tomcatConnectorCustomizers) {
   customizer.customize(connector);  //个性化配置的主要接口
}

//添加个性化connector类  TomcatConnectorCustomizer
public void addConnectorCustomizers(
      TomcatConnectorCustomizer... tomcatConnectorCustomizers) {
   Assert.notNull(tomcatConnectorCustomizers,
         "TomcatConnectorCustomizers must not be null");
   this.tomcatConnectorCustomizers.addAll(Arrays.asList(tomcatConnectorCustomizers));
}  

​   TomcatConnectorCustomizer  自定义个性化connector（实现此类后，将实现类接入到factory中即可）

public interface TomcatConnectorCustomizer {

   /**
    * Customize the connector.
    * @param connector the connector to customize
    */
   void customize(Connector connector);

}