tomcat-uid/webapps/docs/architecture/overview.html - UniIdentify/tomcat - Gitiles

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 </style></head><body bgcolor="#ffffff" text="#000000" link="#525D76" alink="#525D76" vlink="#525D76"><table border="0" width="100%" cellspacing="0"><!--PAGE HEADER--><tr><td><!--PROJECT LOGO--><a href="http://tomcat.apache.org/"><img src="../images/tomcat.gif" align="right" alt="
       The Apache Tomcat Servlet/JSP Container
     " border="0"></a></td><td><h1><font face="arial,helvetica,sanserif">Apache Tomcat 7</font></h1><font face="arial,helvetica,sanserif">Version 7.0.77, Mar 28 2017</font></td><td><!--APACHE LOGO--><a href="http://www.apache.org/"><img src="../images/asf-logo.svg" align="right" alt="Apache Logo" border="0" style="width: 266px;height: 83px;"></a></td></tr></table><table border="0" width="100%" cellspacing="4"><!--HEADER SEPARATOR--><tr><td colspan="2"><hr noshade size="1"></td></tr><tr><!--LEFT SIDE NAVIGATION--><td width="20%" valign="top" nowrap class="noPrint"><p><strong>Links</strong></p><ul><li><a href="../index.html">Docs Home</a></li><li><a href="index.html">Architecture Home</a></li><li><a href="http://wiki.apache.org/tomcat/FAQ">FAQ</a></li><li><a href="#comments_section">User Comments</a></li></ul><p><strong>Contents</strong></p><ul><li><a href="index.html">Contents</a></li><li><a href="overview.html">Overview</a></li><li><a href="startup.html">Server Startup</a></li><li><a href="requestProcess.html">Request Process</a></li></ul></td><!--RIGHT SIDE MAIN BODY--><td width="80%" valign="top" align="left" id="mainBody"><h1>Architecture Overview</h1><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Overview"><strong>Overview</strong></a></font></td></tr><tr><td><blockquote>
 <p>
 This page provides an overview of the Tomcat server architecture.
 </p>
 </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Terms"><strong>Terms</strong></a></font></td></tr><tr><td><blockquote>

 <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Server"><strong>Server</strong></a></font></td></tr><tr><td><blockquote>
 <p>
 In the Tomcat world, a
 <a href="../config/server.html">Server</a> represents the whole container.
 Tomcat provides a default implementation of the
 <a href="../api/org/apache/catalina/Server.html">Server interface</a>
 which is rarely customized by users.
 </p>
 </blockquote></td></tr></table>

 <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Service"><strong>Service</strong></a></font></td></tr><tr><td><blockquote>
 <p>
 A <a href="../config/service.html">Service</a> is an intermediate component
 which lives inside a Server and ties one or more Connectors to exactly one
 Engine.  The Service element is rarely customized by users, as the default
 implementation is simple and sufficient:
 <a href="../api/org/apache/catalina/Service.html">Service interface</a>.
 </p>
 </blockquote></td></tr></table>

 <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Engine"><strong>Engine</strong></a></font></td></tr><tr><td><blockquote>
 <p>
 An
 <a href="../config/engine.html">Engine</a> represents request processing
 pipeline for a specific Service.  As a Service may have multiple Connectors,
 the Engine receives and processes all requests from these connectors, handing
 the response back to the appropriate connector for transmission to the client.
 The <a href="../api/org/apache/catalina/Engine.html">Engine interface</a>
 may be implemented to supply custom Engines, though this is uncommon.
 </p>
 <p>
 Note that the Engine may be used for Tomcat server clustering via the
 jvmRoute parameter.  Read the Clustering documentation for more information.
 </p>
 </blockquote></td></tr></table>

 <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Host"><strong>Host</strong></a></font></td></tr><tr><td><blockquote>
 <p>
 A <a href="../config/host.html">Host</a> is an association of a network name,
 e.g. www.yourcompany.com, to the Tomcat server.  An Engine may contain
 multiple hosts, and the Host element also supports network aliases such as
 yourcompany.com and abc.yourcompany.com.  Users rarely create custom
 <a href="../api/org/apache/catalina/Host.html">Hosts</a>
 because the
 <a href="../api/org/apache/catalina/core/StandardHost.html">StandardHost
 implementation</a> provides significant additional functionality.
 </p>
 </blockquote></td></tr></table>

 <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Connector"><strong>Connector</strong></a></font></td></tr><tr><td><blockquote>
 <p>
 A Connector handles communications with the client.  There are multiple
 connectors available with Tomcat. These include the
 <a href="../config/http.html">HTTP connector</a> which is used for
 most HTTP traffic, especially when running Tomcat as a standalone server,
 and the <a href="../config/ajp.html">AJP connector</a> which implements
 the AJP protocol used when connecting Tomcat to a web server such as
 Apache HTTPD server. Creating a customized connector is a significant
 effort.
 </p>
 </blockquote></td></tr></table>

 <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Context"><strong>Context</strong></a></font></td></tr><tr><td><blockquote>
 <p>
 A
 <a href="../config/context.html">Context</a>
 represents a web application.  A Host may contain multiple
 contexts, each with a unique path.  The
 <a href="../api/org/apache/catalina/Context.html">Context
 interface</a> may be implemented to create custom Contexts, but
 this is rarely the case because the
 <a href="../api/org/apache/catalina/core/StandardContext.html">
 StandardContext</a> provides significant additional functionality.
 </p>
 </blockquote></td></tr></table>
 </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Comments"><strong>Comments</strong></a></font></td></tr><tr><td><blockquote>
 <p>
 Tomcat is designed to be a fast and efficient implementation of the
 Servlet Specification.  Tomcat came about as the reference implementation
 of this specification, and has remained rigorous in adhering to the
 specification.  At the same time, significant attention has been paid
 to Tomcat's performance and it is now on par with other servlet containers,
 including commercial ones.
 </p>
 <p>
 In recent releases of Tomcat, mostly starting with Tomcat 5,
 we have begun efforts to make more aspects of Tomcat manageable via
 JMX.  In addition, the Manager and Admin webapps have been greatly
 enhanced and improved.  Manageability is a primary area of concern
 for us as the product matures and the specification becomes more
 stable.
 </p>
 </blockquote></td></tr></table></td></tr><tr class="noPrint"><td width="20%" valign="top" nowrap class="noPrint"></td><td width="80%" valign="top" align="left"><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="comments_section" id="comments_section"><strong>Comments</strong></a></font></td></tr><tr><td><blockquote><p class="notice"><strong>Notice: </strong>This comments section collects your suggestions
               on improving documentation for Apache Tomcat.<br><br>
               If you have trouble and need help, read
               <a href="http://tomcat.apache.org/findhelp.html">Find Help</a> page
               and ask your question on the tomcat-users
               <a href="http://tomcat.apache.org/lists.html">mailing list</a>.
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         Copyright &copy; 1999-2017, Apache Software Foundation
         </em></font></div></td></tr></table></body></html>
	<html><head><META http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><title>Apache Tomcat 7 Architecture (7.0.77) - Architecture Overview</title><meta name="author" content="Yoav Shapira"><style type="text/css" media="print">
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	</style><style type="text/css">
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	border-collapse: collapse;
	text-align: left;
	}
	table *:not(table) {
	/* Prevent border-collapsing for table child elements like <div> */
	border-collapse: separate;
	}

	th {
	text-align: left;
	}


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	background-color: transparent;
	}
	div.codeBox {
	overflow: auto;
	margin: 1em 0;
	}
	div.codeBox pre {
	margin: 0;
	padding: 4px;
	border: 1px solid #999;
	border-radius: 5px;
	background-color: #eff8ff;
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	background-color: #EEEFFF;
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	background-color: #88b;
	color: #fff;
	}

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	padding: 5px 8px;
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	p.notice {
	border: 1px solid rgb(255, 0, 0);
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	</style></head><body bgcolor="#ffffff" text="#000000" link="#525D76" alink="#525D76" vlink="#525D76"><table border="0" width="100%" cellspacing="0"><!--PAGE HEADER--><tr><td><!--PROJECT LOGO--><a href="http://tomcat.apache.org/"><img src="../images/tomcat.gif" align="right" alt="
	The Apache Tomcat Servlet/JSP Container
	" border="0"></a></td><td><h1><font face="arial,helvetica,sanserif">Apache Tomcat 7</font></h1><font face="arial,helvetica,sanserif">Version 7.0.77, Mar 28 2017</font></td><td><!--APACHE LOGO--><a href="http://www.apache.org/"><img src="../images/asf-logo.svg" align="right" alt="Apache Logo" border="0" style="width: 266px;height: 83px;"></a></td></tr></table><table border="0" width="100%" cellspacing="4"><!--HEADER SEPARATOR--><tr><td colspan="2"><hr noshade size="1"></td></tr><tr><!--LEFT SIDE NAVIGATION--><td width="20%" valign="top" nowrap class="noPrint"><p><strong>Links</strong></p><ul><li><a href="../index.html">Docs Home</a></li><li><a href="index.html">Architecture Home</a></li><li><a href="http://wiki.apache.org/tomcat/FAQ">FAQ</a></li><li><a href="#comments_section">User Comments</a></li></ul><p><strong>Contents</strong></p><ul><li><a href="index.html">Contents</a></li><li><a href="overview.html">Overview</a></li><li><a href="startup.html">Server Startup</a></li><li><a href="requestProcess.html">Request Process</a></li></ul></td><!--RIGHT SIDE MAIN BODY--><td width="80%" valign="top" align="left" id="mainBody"><h1>Architecture Overview</h1><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Overview"><strong>Overview</strong></a></font></td></tr><tr><td><blockquote>
	<p>
	This page provides an overview of the Tomcat server architecture.
	</p>
	</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Terms"><strong>Terms</strong></a></font></td></tr><tr><td><blockquote>

	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Server"><strong>Server</strong></a></font></td></tr><tr><td><blockquote>
	<p>
	In the Tomcat world, a
	<a href="../config/server.html">Server</a> represents the whole container.
	Tomcat provides a default implementation of the
	<a href="../api/org/apache/catalina/Server.html">Server interface</a>
	which is rarely customized by users.
	</p>
	</blockquote></td></tr></table>

	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Service"><strong>Service</strong></a></font></td></tr><tr><td><blockquote>
	<p>
	A <a href="../config/service.html">Service</a> is an intermediate component
	which lives inside a Server and ties one or more Connectors to exactly one
	Engine. The Service element is rarely customized by users, as the default
	implementation is simple and sufficient:
	<a href="../api/org/apache/catalina/Service.html">Service interface</a>.
	</p>
	</blockquote></td></tr></table>

	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Engine"><strong>Engine</strong></a></font></td></tr><tr><td><blockquote>
	<p>
	An
	<a href="../config/engine.html">Engine</a> represents request processing
	pipeline for a specific Service. As a Service may have multiple Connectors,
	the Engine receives and processes all requests from these connectors, handing
	the response back to the appropriate connector for transmission to the client.
	The <a href="../api/org/apache/catalina/Engine.html">Engine interface</a>
	may be implemented to supply custom Engines, though this is uncommon.
	</p>
	<p>
	Note that the Engine may be used for Tomcat server clustering via the
	jvmRoute parameter. Read the Clustering documentation for more information.
	</p>
	</blockquote></td></tr></table>

	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Host"><strong>Host</strong></a></font></td></tr><tr><td><blockquote>
	<p>
	A <a href="../config/host.html">Host</a> is an association of a network name,
	e.g. www.yourcompany.com, to the Tomcat server. An Engine may contain
	multiple hosts, and the Host element also supports network aliases such as
	yourcompany.com and abc.yourcompany.com. Users rarely create custom
	<a href="../api/org/apache/catalina/Host.html">Hosts</a>
	because the
	<a href="../api/org/apache/catalina/core/StandardHost.html">StandardHost
	implementation</a> provides significant additional functionality.
	</p>
	</blockquote></td></tr></table>

	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Connector"><strong>Connector</strong></a></font></td></tr><tr><td><blockquote>
	<p>
	A Connector handles communications with the client. There are multiple
	connectors available with Tomcat. These include the
	<a href="../config/http.html">HTTP connector</a> which is used for
	most HTTP traffic, especially when running Tomcat as a standalone server,
	and the <a href="../config/ajp.html">AJP connector</a> which implements
	the AJP protocol used when connecting Tomcat to a web server such as
	Apache HTTPD server. Creating a customized connector is a significant
	effort.
	</p>
	</blockquote></td></tr></table>

	<table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Context"><strong>Context</strong></a></font></td></tr><tr><td><blockquote>
	<p>
	A
	<a href="../config/context.html">Context</a>
	represents a web application. A Host may contain multiple
	contexts, each with a unique path. The
	<a href="../api/org/apache/catalina/Context.html">Context
	interface</a> may be implemented to create custom Contexts, but
	this is rarely the case because the
	<a href="../api/org/apache/catalina/core/StandardContext.html">
	StandardContext</a> provides significant additional functionality.
	</p>
	</blockquote></td></tr></table>
	</blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Comments"><strong>Comments</strong></a></font></td></tr><tr><td><blockquote>
	<p>
	Tomcat is designed to be a fast and efficient implementation of the
	Servlet Specification. Tomcat came about as the reference implementation
	of this specification, and has remained rigorous in adhering to the
	specification. At the same time, significant attention has been paid
	to Tomcat's performance and it is now on par with other servlet containers,
	including commercial ones.
	</p>
	<p>
	In recent releases of Tomcat, mostly starting with Tomcat 5,
	we have begun efforts to make more aspects of Tomcat manageable via
	JMX. In addition, the Manager and Admin webapps have been greatly
	enhanced and improved. Manageability is a primary area of concern
	for us as the product matures and the specification becomes more
	stable.
	</p>
	</blockquote></td></tr></table></td></tr><tr class="noPrint"><td width="20%" valign="top" nowrap class="noPrint"></td><td width="80%" valign="top" align="left"><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="comments_section" id="comments_section"><strong>Comments</strong></a></font></td></tr><tr><td><blockquote><p class="notice"><strong>Notice: </strong>This comments section collects your suggestions
	on improving documentation for Apache Tomcat.<br><br>
	If you have trouble and need help, read
	<a href="http://tomcat.apache.org/findhelp.html">Find Help</a> page
	and ask your question on the tomcat-users
	<a href="http://tomcat.apache.org/lists.html">mailing list</a>.
	Do not ask such questions here. This is not a Q&A section.<br><br>
	The Apache Comments System is explained <a href="../comments.html">here</a>.
	Comments may be removed by our moderators if they are either
	implemented or considered invalid/off-topic.</p><script type="text/javascript"><!--//--><![CDATA[//><!--
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	Copyright © 1999-2017, Apache Software Foundation
	</em></font></div></td></tr></table></body></html>