tomcat之Catalina

Catalina

在Tomcat4.0版本，将Servlet容器命名为Catalina。

Catalina包含Tomcat所有容器组件，通过松耦合的方式集成Coyote，以及完成按照请求协议进行数据读写，同时还包括启动入口和Shell程序。Catalina解析server.xml文件来创建Server，并将其内的各组件创建出来

Tomcat本质上是一款Servlet容器，Catalina是Tomcat的核心，其他模块均为Catalina提供支撑。通过Coyote模块提供链接通信，Jasper模块提供JSP引擎，Naming提供JNDI服务，Juli提供日志服务。

Digester

Catalina使用Digester解析XML(server.xml)配置文件并创建应用服务器。

Digester是一款将XML转换为java对象的事件驱动型工具，是对SAX的高层次封装。

创建Server

Server由Catalina进行管理，Catalina是整个Tomcat的管理类

// 使用load、start、stop来管理了整个服务器的生命周期
// 根据conf/server.xml创建Server并调用server的init方法来进行初始化
public void load()
// 启动服务器
public void start()
// 停止服务器
public void stop()

Server解析

Server接口表示Catalina的整个Servlet引擎，囊括了所有的组件，标准实现是StandardServer

解析server.xml文件，文件示例

<?xml version="1.0" encoding="UTF-8"?>

<Server port="8005" shutdown="SHUTDOWN">
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />
  
  <!--APR library loader. Documentation at /docs/apr.html -->
  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
  <!-- Prevent memory leaks due to use of particular java/javax APIs-->
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

  <!-- Global JNDI resources
       Documentation at /docs/jndi-resources-howto.html
  -->
  <GlobalNamingResources>
    <!-- Editable user database that can also be used by
         UserDatabaseRealm to authenticate users
    -->
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  </GlobalNamingResources>

  <!-- A "Service" is a collection of one or more "Connectors" that share
       a single "Container" Note:  A "Service" is not itself a "Container",
       so you may not define subcomponents such as "Valves" at this level.
       Documentation at /docs/config/service.html
   -->
  <Service name="Catalina">


    <!-- A "Connector" represents an endpoint by which requests are received
         and responses are returned. Documentation at :
         Java HTTP Connector: /docs/config/http.html
         Java AJP  Connector: /docs/config/ajp.html
         APR (HTTP/AJP) Connector: /docs/apr.html
         Define a non-SSL/TLS HTTP/1.1 Connector on port 8080
    -->
    <Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" URIEncoding="UTF-8" relaxedPathChars="|{}[],%"
      relaxedQueryChars="|{}[],%"/>
    

    <!-- An Engine represents the entry point (within Catalina) that processes
         every request.  The Engine implementation for Tomcat stand alone
         analyzes the HTTP headers included with the request, and passes them
         on to the appropriate Host (virtual host).
         Documentation at /docs/config/engine.html -->

    <!-- You should set jvmRoute to support load-balancing via AJP ie :
    <Engine name="Catalina" defaultHost="localhost" jvmRoute="jvm1">
    -->
    <Engine name="Catalina" defaultHost="localhost">

      <!-- Use the LockOutRealm to prevent attempts to guess user passwords
           via a brute-force attack -->
      <Realm className="org.apache.catalina.realm.LockOutRealm">
        <!-- This Realm uses the UserDatabase configured in the global JNDI
             resources under the key "UserDatabase".  Any edits
             that are performed against this UserDatabase are immediately
             available for use by the Realm.  -->
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
               resourceName="UserDatabase"/>
      </Realm>

      <Host name="localhost"  appBase="webapps"
            unpackWARs="true" autoDeploy="true">

        <!-- Access log processes all example.
             Documentation at: /docs/config/valve.html
             Note: The pattern used is equivalent to using pattern="common" -->
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log" suffix=".txt"
               pattern="%h %l %u %t &quot;%r&quot; %s %b" />

      </Host>
    </Engine>
  </Service>
</Server>

Catalina.createStartDigester

创建Server实例

// Server的默认实现类org.apache.catalina.core.StandardServer,可以使用className指定自己的实现类
digester.addObjectCreate("Server",
                         "org.apache.catalina.core.StandardServer",
                         "className");
digester.addSetProperties("Server");
digester.addSetNext("Server",
                    "setServer",
                    "org.apache.catalina.Server");

创建全局J2EE企业命名上下文

digester.addObjectCreate("Server/GlobalNamingResources",
                         "org.apache.catalina.deploy.NamingResourcesImpl");
digester.addSetProperties("Server/GlobalNamingResources");
digester.addSetNext("Server/GlobalNamingResources",
                    "setGlobalNamingResources",
                    "org.apache.catalina.deploy.NamingResourcesImpl");


<GlobalNamingResources>
    <!-- Editable user database that can also be used by
         UserDatabaseRealm to authenticate users
    -->
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  </GlobalNamingResources>

为Server添加生命周期监听器

digester.addObjectCreate("Server/Listener",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties("Server/Listener");
digester.addSetNext("Server/Listener",
                    "addLifecycleListener",
                    "org.apache.catalina.LifecycleListener");

<!-- 在Server初始化之前打印操作系统、JVM以及服务器的版本信息 -->
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />
  <!-- Security listener. Documentation at /docs/config/listeners.html
  <Listener className="org.apache.catalina.security.SecurityListener" />
  -->
  <!--APR library loader. Documentation at /docs/apr.html -->
    <!-- 在Server初始化之前加载ARP库，并于Server停止之后销毁 -->
  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
  <!-- Prevent memory leaks due to use of particular java/javax APIs-->
    <!-- 在Server初始化之前调用，以解决单例对象创建导致的JVM内存泄露问题以及锁文件问题  -->
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
    <!-- 在Server启动时，将JNDI资源注册为MBean进行管理 -->
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
    <!-- 用于在Context停止时重建Executor池中的线程，避免导致内存泄漏 -->
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

构造Service实例

// Service的默认实现类org.apache.catalina.core.StandardService,可以使用className指定自己的实现类
digester.addObjectCreate("Server/Service",
                         "org.apache.catalina.core.StandardService",
                         "className");
digester.addSetProperties("Server/Service");
digester.addSetNext("Server/Service",
                    "addService",
                    "org.apache.catalina.Service");

为Service添加生命周期监听器

默认情况下，Service下没有指定监听器

digester.addObjectCreate("Server/Service/Listener",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties("Server/Service/Listener");
digester.addSetNext("Server/Service/Listener",
                    "addLifecycleListener",
                    "org.apache.catalina.LifecycleListener");

为Service添加Executor

Catalina共享Executor的级别为Service。Catalina默认情况下未配置Executor，即不共享

// 默认实现为org.apache.catalina.core.StandardThreadExecutor
digester.addObjectCreate("Server/Service/Executor",
                 "org.apache.catalina.core.StandardThreadExecutor",
                 "className");
digester.addSetProperties("Server/Service/Executor");

digester.addSetNext("Server/Service/Executor",
                    "addExecutor",
                    "org.apache.catalina.Executor");

为Service添加Connector

digester.addRule("Server/Service/Connector",
                 new ConnectorCreateRule());
digester.addRule("Server/Service/Connector",
                 new SetAllPropertiesRule(new String[]{"executor", "sslImplementationName"}));
digester.addSetNext("Server/Service/Connector",
                    "addConnector",
                    "org.apache.catalina.connector.Connector");

<Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" URIEncoding="UTF-8" relaxedPathChars="|{}[],%"
      relaxedQueryChars="|{}[],%"/>

为Connector添加虚拟主机SSL配置

digester.addObjectCreate("Server/Service/Connector/SSLHostConfig",
                         "org.apache.tomcat.util.net.SSLHostConfig");
digester.addSetProperties("Server/Service/Connector/SSLHostConfig");
digester.addSetNext("Server/Service/Connector/SSLHostConfig",
        "addSslHostConfig",
        "org.apache.tomcat.util.net.SSLHostConfig");

digester.addRule("Server/Service/Connector/SSLHostConfig/Certificate",
                 new CertificateCreateRule());
digester.addRule("Server/Service/Connector/SSLHostConfig/Certificate",
                 new SetAllPropertiesRule(new String[]{"type"}));
digester.addSetNext("Server/Service/Connector/SSLHostConfig/Certificate",
                    "addCertificate",
                    "org.apache.tomcat.util.net.SSLHostConfigCertificate");

digester.addObjectCreate("Server/Service/Connector/SSLHostConfig/OpenSSLConf",
                         "org.apache.tomcat.util.net.openssl.OpenSSLConf");
digester.addSetProperties("Server/Service/Connector/SSLHostConfig/OpenSSLConf");
digester.addSetNext("Server/Service/Connector/SSLHostConfig/OpenSSLConf",
                    "setOpenSslConf",
                    "org.apache.tomcat.util.net.openssl.OpenSSLConf");

digester.addObjectCreate("Server/Service/Connector/SSLHostConfig/OpenSSLConf/OpenSSLConfCmd",
                         "org.apache.tomcat.util.net.openssl.OpenSSLConfCmd");
digester.addSetProperties("Server/Service/Connector/SSLHostConfig/OpenSSLConf/OpenSSLConfCmd");
digester.addSetNext("Server/Service/Connector/SSLHostConfig/OpenSSLConf/OpenSSLConfCmd",
                    "addCmd",
                    "org.apache.tomcat.util.net.openssl.OpenSSLConfCmd");

为Connector添加生命周期监听器

digester.addObjectCreate("Server/Service/Connector/Listener",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties("Server/Service/Connector/Listener");
digester.addSetNext("Server/Service/Connector/Listener",
                    "addLifecycleListener",
                    "org.apache.catalina.LifecycleListener");

为Connector添加升级协议

digester.addObjectCreate("Server/Service/Connector/UpgradeProtocol",
                                  null, // MUST be specified in the element
                                  "className");
digester.addSetProperties("Server/Service/Connector/UpgradeProtocol");
digester.addSetNext("Server/Service/Connector/UpgradeProtocol",
                    "addUpgradeProtocol",
                    "org.apache.coyote.UpgradeProtocol");

添加子元素解析规则

digester.addRuleSet(new NamingRuleSet("Server/GlobalNamingResources/"));
digester.addRuleSet(new EngineRuleSet("Server/Service/"));
digester.addRuleSet(new HostRuleSet("Server/Service/Engine/"));
digester.addRuleSet(new ContextRuleSet("Server/Service/Engine/Host/"));
addClusterRuleSet(digester, "Server/Service/Engine/Host/Cluster/");
digester.addRuleSet(new NamingRuleSet("Server/Service/Engine/Host/Context/"));

// When the 'engine' is found, set the parentClassLoader.
digester.addRule("Server/Service/Engine",
                 new SetParentClassLoaderRule(parentClassLoader));
addClusterRuleSet(digester, "Server/Service/Engine/Cluster/");

Engine的解析

EngineRuleSet类中包含了Engine的解析过程

创建Engine实例

//Catalina默认实现org.apache.catalina.core.StandardEngine
digester.addObjectCreate(prefix + "Engine",
                         "org.apache.catalina.core.StandardEngine",
                         "className");
digester.addSetProperties(prefix + "Engine");
//为Engine添加生命周期监听器EngineConfig,用于打印启动和停止日志，默认的监听器，不是由server.xml配置
digester.addRule(prefix + "Engine",
                 new LifecycleListenerRule
                 ("org.apache.catalina.startup.EngineConfig",
                  "engineConfigClass"));
digester.addSetNext(prefix + "Engine",
                    "setContainer",
                    "org.apache.catalina.Engine");

为Engine添加集群配置

digester.addObjectCreate(prefix + "Engine/Cluster",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Engine/Cluster");
digester.addSetNext(prefix + "Engine/Cluster",
                    "setCluster",
                    "org.apache.catalina.Cluster");

为Engine添加生命周期监听器

// 由server.xml配置
digester.addObjectCreate(prefix + "Engine/Listener",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Engine/Listener");
digester.addSetNext(prefix + "Engine/Listener",
                    "addLifecycleListener",
                    "org.apache.catalina.LifecycleListener");

为Engine添加安全配置

digester.addRuleSet(new RealmRuleSet(prefix + "Engine/"));

digester.addObjectCreate(prefix + "Engine/Valve",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Engine/Valve");
digester.addSetNext(prefix + "Engine/Valve",
                    "addValve",
                    "org.apache.catalina.Valve");

Host的解析

HostRuleSet中包含了Host的解析

创建Host实例

//catalina默认实现为org.apache.catalina.core.StandardHost
digester.addObjectCreate(prefix + "Host",
                         "org.apache.catalina.core.StandardHost",
                         "className");
digester.addSetProperties(prefix + "Host");
digester.addRule(prefix + "Host",
                 new CopyParentClassLoaderRule());
//添加生命周期，默认添加，不是由server.xml控制的
digester.addRule(prefix + "Host",
                 new LifecycleListenerRule
                 ("org.apache.catalina.startup.HostConfig",
                  "hostConfigClass"));
digester.addSetNext(prefix + "Host",
                    "addChild",
                    "org.apache.catalina.Container");
// 设置别名
digester.addCallMethod(prefix + "Host/Alias",
                       "addAlias", 0);

为Host添加集群

digester.addObjectCreate(prefix + "Host/Cluster",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Host/Cluster");
digester.addSetNext(prefix + "Host/Cluster",
                    "setCluster",
                    "org.apache.catalina.Cluster");

为Host添加生命周期

digester.addObjectCreate(prefix + "Host/Listener",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Host/Listener");
digester.addSetNext(prefix + "Host/Listener",
                    "addLifecycleListener",
                    "org.apache.catalina.LifecycleListener");

为Host添加安全配置

digester.addRuleSet(new RealmRuleSet(prefix + "Host/"));

digester.addObjectCreate(prefix + "Host/Valve",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Host/Valve");
digester.addSetNext(prefix + "Host/Valve",
                    "addValve",
                    "org.apache.catalina.Valve");

Context的解析

ContextRuleSet类中包含Context的解析

Catalina中Context配置并非来源于一处，此处仅介绍server.xm中的配置，大多数情况下，不需要在server.xml中配置Context，而是由HostConfig自动扫描部署目录，以context.xml文件为基础进行解析创建。

Context实例化

//使用server.xml创建时，create为true；通过HostConfig创建时create为false
if (create) {
    digester.addObjectCreate(prefix + "Context",
            "org.apache.catalina.core.StandardContext", "className");
    digester.addSetProperties(prefix + "Context");
} else {
    digester.addRule(prefix + "Context", new SetContextPropertiesRule());
}

if (create) {
    digester.addRule(prefix + "Context",
                     new LifecycleListenerRule
                         ("org.apache.catalina.startup.ContextConfig",
                          "configClass"));
    digester.addSetNext(prefix + "Context",
                        "addChild",
                        "org.apache.catalina.Container");
}

为Context添加生命周期监听器

digester.addObjectCreate(prefix + "Context/Listener",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Context/Listener");
digester.addSetNext(prefix + "Context/Listener",
                    "addLifecycleListener",
                    "org.apache.catalina.LifecycleListener");

为Context指定类加载器

//默认为org.apache.catalina.loader.WebappLoader
digester.addObjectCreate(prefix + "Context/Loader",
                    "org.apache.catalina.loader.WebappLoader",
                    "className");
digester.addSetProperties(prefix + "Context/Loader");
digester.addSetNext(prefix + "Context/Loader",
                    "setLoader",
                    "org.apache.catalina.Loader");

为Context添加会话管理器

// 默认为org.apache.catalina.session.StandardManager
digester.addObjectCreate(prefix + "Context/Manager",
                         "org.apache.catalina.session.StandardManager",
                         "className");
digester.addSetProperties(prefix + "Context/Manager");
digester.addSetNext(prefix + "Context/Manager",
                    "setManager",
                    "org.apache.catalina.Manager");
// 指定会话存储方式
digester.addObjectCreate(prefix + "Context/Manager/Store",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Context/Manager/Store");
digester.addSetNext(prefix + "Context/Manager/Store",
                    "setStore",
                    "org.apache.catalina.Store");
//指定会话标识生成器
digester.addObjectCreate(prefix + "Context/Manager/SessionIdGenerator",
                         "org.apache.catalina.util.StandardSessionIdGenerator",
                         "className");
digester.addSetProperties(prefix + "Context/Manager/SessionIdGenerator");
digester.addSetNext(prefix + "Context/Manager/SessionIdGenerator",
                    "setSessionIdGenerator",
                    "org.apache.catalina.SessionIdGenerator");

为Context添加初始化参数

可以在context.xml文件中添加初始化参数，已实现所有Web应用中的复用，而不必每个Web应用重复配置

digester.addObjectCreate(prefix + "Context/Parameter",
                         "org.apache.tomcat.util.descriptor.web.ApplicationParameter");
digester.addSetProperties(prefix + "Context/Parameter");
digester.addSetNext(prefix + "Context/Parameter",
                    "addApplicationParameter",
                    "org.apache.tomcat.util.descriptor.web.ApplicationParameter");

为Context添加安全配置以及Web资源配置

digester.addRuleSet(new RealmRuleSet(prefix + "Context/"));

digester.addObjectCreate(prefix + "Context/Resources",
                         "org.apache.catalina.webresources.StandardRoot",
                         "className");
digester.addSetProperties(prefix + "Context/Resources");
digester.addSetNext(prefix + "Context/Resources",
                    "setResources",
                    "org.apache.catalina.WebResourceRoot");

digester.addObjectCreate(prefix + "Context/Resources/PreResources",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Context/Resources/PreResources");
digester.addSetNext(prefix + "Context/Resources/PreResources",
                    "addPreResources",
                    "org.apache.catalina.WebResourceSet");

digester.addObjectCreate(prefix + "Context/Resources/JarResources",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Context/Resources/JarResources");
digester.addSetNext(prefix + "Context/Resources/JarResources",
                    "addJarResources",
                    "org.apache.catalina.WebResourceSet");

digester.addObjectCreate(prefix + "Context/Resources/PostResources",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Context/Resources/PostResources");
digester.addSetNext(prefix + "Context/Resources/PostResources",
                    "addPostResources",
                    "org.apache.catalina.WebResourceSet");

为Context添加资源链接

//用于J2EE命名服务
digester.addObjectCreate(prefix + "Context/ResourceLink",
        "org.apache.tomcat.util.descriptor.web.ContextResourceLink");
digester.addSetProperties(prefix + "Context/ResourceLink");
digester.addRule(prefix + "Context/ResourceLink",
        new SetNextNamingRule("addResourceLink",
                "org.apache.tomcat.util.descriptor.web.ContextResourceLink"));

为Context添加拦截器Value

digester.addObjectCreate(prefix + "Context/Valve",
                         null, // MUST be specified in the element
                         "className");
digester.addSetProperties(prefix + "Context/Valve");
digester.addSetNext(prefix + "Context/Valve",
                    "addValve",
                    "org.apache.catalina.Valve");

为Context添加守护资源配置

<!-- context.xml -->
<Context>

    <!-- Default set of monitored resources. If one of these changes, the    -->
    <!-- web application will be reloaded.                                   -->
    <WatchedResource>WEB-INF/web.xml</WatchedResource>
    <WatchedResource>${catalina.base}/conf/web.xml</WatchedResource>

    <!-- Uncomment this to disable session persistence across Tomcat restarts -->
    <!--
    <Manager pathname="" />
    -->
</Context>

//WatchedResource标签用于为Context添加监视器，当这些资源发生变更时，Web应用将会被重新加载，默认为WEB-INF/web.xml
digester.addCallMethod(prefix + "Context/WatchedResource",
                       "addWatchedResource", 0);
//WrapperLifecycle标签用于为Context添加一个生命周期监听器，此类的实例并非添加到Context上，而是添加到Context包含的Wrapper上
digester.addCallMethod(prefix + "Context/WrapperLifecycle",
                       "addWrapperLifecycle", 0);
//WrapperListener标签用于为Context添加一个容器监听类，添加到Wrapper上
digester.addCallMethod(prefix + "Context/WrapperListener",
                       "addWrapperListener", 0);
//JarScanner标签用于为Context添加一个Jar扫描器
digester.addObjectCreate(prefix + "Context/JarScanner",
                         "org.apache.tomcat.util.scan.StandardJarScanner",
                         "className");
digester.addSetProperties(prefix + "Context/JarScanner");
digester.addSetNext(prefix + "Context/JarScanner",
                    "setJarScanner",
                    "org.apache.tomcat.JarScanner");
//JarScanFilter为JarScanner指定一个过滤器
digester.addObjectCreate(prefix + "Context/JarScanner/JarScanFilter",
                         "org.apache.tomcat.util.scan.StandardJarScanFilter",
                         "className");
digester.addSetProperties(prefix + "Context/JarScanner/JarScanFilter");
digester.addSetNext(prefix + "Context/JarScanner/JarScanFilter",
                    "setJarScanFilter",
                    "org.apache.tomcat.JarScanFilter");

为Context添加Cookie处理器

digester.addObjectCreate(prefix + "Context/CookieProcessor",
                         "org.apache.tomcat.util.http.Rfc6265CookieProcessor",
                         "className");
digester.addSetProperties(prefix + "Context/CookieProcessor");
digester.addSetNext(prefix + "Context/CookieProcessor",
                    "setCookieProcessor",
                    "org.apache.tomcat.util.http.CookieProcessor");