Tomcat and Jetty

蔚落 2024-03-25 20:37 98阅读 0赞

版本：spring-boot-2.2.1.RELEASE.jar，tomcat-embed-core-9.0.27.jar，jetty:9.4.22.v20191022�

### WebServer生命周期 ###

1.  Spring web应用上下文刷新时（org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext\#onRefresh），创建org.springframework.boot.web.server.WebServer
2.  Spring web应用上下文刷新完成时（org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext\#finishRefresh），启动org.springframework.boot.web.server.WebServer
3.  Spring web应用上下文关闭时（org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext\#stopAndRelease），关闭释放org.springframework.boot.web.server.WebServer

### jetty ###

#### 配置web上下文 ####

通过编程式配置gzip同样不会生效，会被ServletWebServerFactoryCustomizer�重写，正确方法增加server配置：server.compression.enabled=true�

@Bean
        public ServletWebServerFactory servletContainer() {
            JettyServletWebServerFactory jetty = new JettyServletWebServerFactory();
            QueuedThreadPool tp = new QueuedThreadPool(200,8, 60000, new BlockingArrayQueue<>(1));
            jetty.setThreadPool(tp);
            jetty.setPort(Integer.parseInt(serverPort.trim()));
            MyJettyServerCustomizer myJettyServerCustomizer = new MyJettyServerCustomizer();
            jetty.addServerCustomizers(myJettyServerCustomizer);
            Compression compression = new Compression();
            compression.setEnabled(true);
            // 注意不生效，会被org.springframework.boot.autoconfigure.web.servlet.ServletWebServerFactoryCustomizer#customize重写
            jetty.setCompression(compression);
            jetty.setServerHeader("my-server-header-value");
            return jetty;
        }

#### 创建jetty WebServer ####

org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory\#getWebServer�

1.  创建上下文JettyEmbeddedWebAppContext�
2.  创建server：org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory\#createServer
3.  配置web应用上下文：org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory\#configureWebAppContext
4.  为server设置handler：org.eclipse.jetty.server.handler.HandlerWrapper\#setHandler
5.  按需配置ssl：org.springframework.boot.web.embedded.jetty.JettyServletWebServerFactory\#customizeSsl
6.  按需配置server：org.springframework.boot.web.embedded.jetty.JettyServerCustomizer\#customize

#### 启动jetty WebServer ####

org.springframework.boot.web.embedded.jetty.JettyWebServer\#start

1.  设置server连接器数组：org.eclipse.jetty.server.Server\#setConnectors
2.  启动server：org.eclipse.jetty.server.Server\#doStart
    
    1.  启动server管理的bean，例如：JettyEmbeddedWebAppContext
    2.  回调org.eclipse.jetty.webapp.WebAppContext\#doStart，WebAppContext(JettyEmbeddedWebAppContext父类）
    3.  回调WebAppContext配置pre,configure,post：org.eclipse.jetty.webapp.Configuration
3.  延迟初始化Handler：org.springframework.boot.web.embedded.jetty.JettyWebServer\#handleDeferredInitialize
4.  启动连接器：org.eclipse.jetty.server.Connector，启动server时也会启动连接器，但是连接器默认情况下为空数组，主要留给自定义业务场景扩展使用，例如：在创建server时就设置好连接器

#### handler优先级 ####

org.eclipse.jetty.servlet.ServletContextHandler\#relinkHandlers  
默认优先级如下，背景（配置了serverHeader与压缩）  
handler链：JettyHandlerWrappers.ServerHeaderHandler->GzipHandler->JettyEmbeddedWebAppContext->SessionHandler->ConstraintSecurityHandler�->JettyEmbeddedServletHandler�

handler执行链路  
![jetty-handle.drawio.png][]

#### 架构图 ####

server的每个组件（server容器管理的bean）均可插拔，自定义组装自己的服务器容器，生命周期通过Server父类管理：org.eclipse.jetty.util.component.ContainerLifeCycle  
![jetty-architecture.drawio.png][]

### Tomcat ###

#### 配置web上下文 ####

org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory\#prepareContext

1.  创建上下文：org.springframework.boot.web.embedded.tomcat.TomcatEmbeddedContext
    
    1.  创建Pipeline：org.apache.catalina.core.StandardPipeline\#StandardPipeline(org.apache.catalina.Container)
        
        1.  container�：org.springframework.boot.web.embedded.tomcat.TomcatEmbeddedContext
        2.  basic�：org.apache.catalina.core.StandardEngineValve\#StandardEngineValve，如果存在basic oldValve则停止，将新的basic Valve设置在管道尾巴节点
2.  按需配置default，jsp servlet
3.  将context�添加至Host child
4.  为context设置生命周期监听器：org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory\#contextLifecycleListeners
5.  遍历org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory\#contextValves添加至context pipeline
6.  为context设置ErrorPage�
7.  配置session：org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory\#configureSession
8.  回调上下文自定义配置：org.springframework.boot.web.embedded.tomcat.TomcatContextCustomizer\#customize

#### 创建tomcat WebServer ####

org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory\#getWebServer

1.  创建Tomcat：org.apache.catalina.startup.Tomcat\#Tomcat
2.  创建Connector：org.apache.catalina.connector.Connector\#Connector(java.lang.String)
    
    1.  创建ProtocolHandler�：org.apache.coyote.http11.Http11NioProtocol
    2.  调用父类启动协议：org.apache.coyote.AbstractProtocol\#start
    3.  启动EndPoint：org.apache.tomcat.util.net.NioEndpoint->org.apache.tomcat.util.net.NioEndpoint\#startInternal
    4.  启动selector轮训器：org.apache.tomcat.util.net.NioEndpoint.Poller\#Poller
    5.  处理数据：org.apache.tomcat.util.net.NioEndpoint.Poller\#processKey，例如：读数据=org.apache.tomcat.util.net.AbstractEndpoint\#processSocket(socketWrapper, SocketEvent.OPEN\_READ, true�)
    6.  创建Socket处理器SocketProcessorBase�：org.apache.tomcat.util.net.NioEndpoint\#createSocketProcessor
    7.  获取handler处理数据：org.apache.tomcat.util.net.AbstractEndpoint\#getHandler-》org.apache.coyote.AbstractProtocol.ConnectionHandler\#process
    8.  获取Processor处理数据：org.apache.coyote.http11.Http11Processor-》org.apache.coyote.AbstractProcessorLight\#process-》org.apache.coyote.http11.Http11Processor\#service
    9.  获取适配器处理数据：org.apache.coyote.AbstractProcessor\#getAdapter-》org.apache.catalina.connector.CoyoteAdapter\#service
    10. 解析request请求之后调用connector�->service->container->pipeline处理数据：org.apache.catalina.connector.CoyoteAdapter\#service-》org.apache.catalina.connector.CoyoteAdapter\#postParseRequest�
3.  创建Server：org.apache.catalina.core.StandardServer\#StandardServer
4.  创建Service：org.apache.catalina.core.StandardService
5.  配置连接器：org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory\#customizeConnector
6.  创建Engine：org.apache.catalina.core.StandardEngine\#StandardEngine
    
    1.  创建Pipeline：org.apache.catalina.core.StandardPipeline\#StandardPipeline(org.apache.catalina.Container)
        
        1.  container�：org.apache.catalina.core.StandardEngine
        2.  basic�：org.apache.catalina.core.StandardEngineValve\#StandardEngineValve，如果存在basic oldValve则停止，将新的basic Valve设置在管道尾巴节点
7.  创建Host：org.apache.catalina.core.StandardHost\#StandardHost
    
    1.  创建Pipeline
        
        1.  container�：org.apache.catalina.core.StandardHost
        2.  basic：同Engine
8.  创建WebServer：org.springframework.boot.web.embedded.tomcat.TomcatWebServer\#TomcatWebServer(org.apache.catalina.startup.Tomcat, boolean)
    
    1.  初始化WebServer：org.springframework.boot.web.embedded.tomcat.TomcatWebServer\#initialize

#### 启动tomcat WebServer ####

调用父类方法：org.apache.catalina.util.LifecycleBase\#start

1.  初始化：org.apache.catalina.util.LifecycleBase\#init-》initInternal�
2.  启动：org.apache.catalina.util.LifecycleBase\#startInternal
3.  停止：org.apache.catalina.util.LifecycleBase\#stop-》stopInternal�

org.apache.catalina.core.StandardServer\#startInternal

1.  遍历services�启动Service：org.apache.catalina.core.StandardService\#startInternal
2.  启动Engine：org.apache.catalina.core.StandardEngine\#startInternal
    
    1.  如果存在子容器，启动子容器：org.apache.catalina.core.ContainerBase\#children
    2.  启动pipeline：org.apache.catalina.core.StandardPipeline\#startInternal
    3.  设置状态为STARTING�
3.  启动Executor�：org.apache.catalina.core.StandardThreadExecutor\#startInternal
    
    1.  默认线程池配置，min=25，max=200，name前缀=tomcat-exec-�，队列为LinkedBlockingQueue�子类
4.  启动连接器：org.apache.catalina.connector.Connector\#startInternal
5.  启动完成设置状态为STARTED：org.apache.catalina.util.LifecycleBase\#start

#### Pipeline优先级 ####

下面的管道优先级由高到低的顺序为：由上到下，由左到右

##### Engine pipeline #####

null -> StandardEngineValve\[StandardEngine\[Tomcat\]\]

##### Host pipeline #####

ErrorReportValve\[StandardEngine\[Tomcat\].StandardHost\[localhost\]\]->StandardHostValve\[StandardEngine\[Tomcat\].StandardHost\[localhost\]\]

##### Context pipeline #####

NonLoginAuthenticator\[StandardEngine\[Tomcat\].StandardHost\[localhost\].TomcatEmbeddedContext\[\]\]->StandardContextValve\[StandardEngine\[Tomcat\].StandardHost\[localhost\].TomcatEmbeddedContext\[\]\]

##### DispatcherServlet pipeline #####

null -> StandardWrapperValve\[StandardEngine\[Tomcat\].StandardHost\[localhost\].TomcatEmbeddedContext\[\].StandardWrapper\[dispatcherServlet\]\]

##### Valve调用链路 #####

管道调用链路入口参考“创建Connector”部分的子流程，入口：

1.  解析request请求之后调用connector�->service->container->pipeline处理数据：org.apache.catalina.connector.CoyoteAdapter\#service-》org.apache.catalina.connector.CoyoteAdapter\#postParseRequest�

![tomcat-valve-invoke.png][]

#### 架构图 ####

StandardHost child是上下文TomcatEmbeddedContext  
![tomcat-architecture.drawio.png][]

### 总结 ###

1.  Jetty服务架构更加简洁，且可插拔特性很适合定制一些个性化功能
2.  Tomcat服务架构相对复杂些，且容器的组件之间存在强依赖。Tomcat的架构中可以看到它支持配置多个host端口，Jetty是不支持的，需要启动多个JettyWebServer支持
3.  Jetty的Handler设计略复杂，scope抽象的应用场景没有很明显的优势，甚至有些与handle混淆，有些Handler仅实现了scope抽象，handle抽象用不到直接传递至下一个节点。整个handler链有点像是层高为2的跳跃表
4.  Tomcat的管道设计相对简单，多个不同的管道可以通过特殊的Valve阀门对接，使得串连为一整条完整的链路，更易理解

对于二者没有谁优谁差吧，阅读源码梳理其架构与链路，可以效仿实现来支撑多变的业务需求。比如：过滤漏斗，可以按照不同的业务线组装不同的过滤漏斗，来匹配合适的订单与配送员。每个过滤漏斗可以支持动态插拔过滤器

[jetty-handle.drawio.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/25/9b9d64ba2fb5463ba74af5568bf4a838.png
[jetty-architecture.drawio.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/25/a801804b50704195bf46a028581fbc8c.png
[tomcat-valve-invoke.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/25/3770d0af5c2148699168b4106f4168b9.png
[tomcat-architecture.drawio.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/25/e5cb3ddfbe544ce1bef6a247d6844993.png