| 1 | <html><head><META http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><title>Apache Tomcat Configuration Reference - The Loader Component</title><meta value="Craig R. McClanahan" name="author"><meta value="craigmcc@apache.org" name="email"></head><body vlink="#525D76" alink="#525D76" link="#525D76" text="#000000" bgcolor="#ffffff"><table cellspacing="0" width="100%" border="0"><!--PAGE HEADER--><tr><td><!--PROJECT LOGO--><a href="http://tomcat.apache.org/"><img border="0" alt=" |
|---|
| 2 | The Apache Tomcat Servlet/JSP Container |
|---|
| 3 | " align="right" src="../images/tomcat.gif"></a></td><td><font face="arial,helvetica,sanserif"><h1>Apache Tomcat 6.0</h1></font></td><td><!--APACHE LOGO--><a href="http://www.apache.org/"><img border="0" alt="Apache Logo" align="right" src="../images/asf-logo.gif"></a></td></tr></table><table cellspacing="4" width="100%" border="0"><!--HEADER SEPARATOR--><tr><td colspan="2"><hr size="1" noshade></td></tr><tr><!--LEFT SIDE NAVIGATION--><td nowrap="true" valign="top" width="20%"><p><strong>Links</strong></p><ul><li><a href="../index.html">Docs Home</a></li><li><a href="index.html">Config Ref. Home</a></li></ul><p><strong>Top Level Elements</strong></p><ul><li><a href="server.html">Server</a></li><li><a href="service.html">Service</a></li></ul><p><strong>Executors</strong></p><ul><li><a href="executor.html">Executor</a></li></ul><p><strong>Connectors</strong></p><ul><li><a href="http.html">HTTP</a></li><li><a href="ajp.html">AJP</a></li></ul><p><strong>Containers</strong></p><ul><li><a href="context.html">Context</a></li><li><a href="engine.html">Engine</a></li><li><a href="host.html">Host</a></li><li><a href="cluster.html">Cluster</a></li></ul><p><strong>Nested Components</strong></p><ul><li><a href="globalresources.html">Global Resources</a></li><li><a href="loader.html">Loader</a></li><li><a href="manager.html">Manager</a></li><li><a href="realm.html">Realm</a></li><li><a href="resources.html">Resources</a></li><li><a href="valve.html">Valve</a></li></ul><p><strong>Cluster Elements</strong></p><ul><li><a href="cluster.html">Cluster</a></li><li><a href="cluster-manager.html">Manager</a></li><li><a href="cluster-channel.html">Channel</a></li><li><a href="cluster-membership.html">Channel/Membership</a></li><li><a href="cluster-sender.html">Channel/Sender</a></li><li><a href="cluster-receiver.html">Channel/Receiver</a></li><li><a href="cluster-interceptor.html">Channel/Interceptor</a></li><li><a href="cluster-valve.html">Valve</a></li><li><a href="cluster-deployer.html">Deployer</a></li><li><a href="cluster-listener.html">ClusterListener</a></li></ul><p><strong>Global Settings</strong></p><ul><li><a href="systemprops.html">System properties</a></li></ul></td><!--RIGHT SIDE MAIN BODY--><td align="left" valign="top" width="80%"><table cellspacing="4" width="100%" border="0"><tr><td valign="top" align="left"><h1>Apache Tomcat Configuration Reference</h1><h2>The Loader Component</h2></td><td nowrap="true" valign="top" align="right"><small><a href="printer/loader.html"><img alt="Printer Friendly Version" border="0" src="../images/printer.gif"><br>print-friendly<br>version |
|---|
| 4 | </a></small></td></tr></table><table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#525D76"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Introduction"><strong>Introduction</strong></a></font></td></tr><tr><td><blockquote> |
|---|
| 5 | |
|---|
| 6 | <p>The <strong>Loader</strong> element represents the <em>web |
|---|
| 7 | application class loader</em> that will be used to load Java |
|---|
| 8 | classes and resources for your web application. Such |
|---|
| 9 | a class loader must follow the requirements of the Servlet |
|---|
| 10 | Specification, and load classes from the following locations:</p> |
|---|
| 11 | <ul> |
|---|
| 12 | <li>From the <code>/WEB-INF/classes</code> directory inside your |
|---|
| 13 | web application.</li> |
|---|
| 14 | <li>From JAR files in the <code>/WEB-INF/lib</code> directory |
|---|
| 15 | inside your web application.</li> |
|---|
| 16 | <li>From resources made available by Catalina to all web |
|---|
| 17 | applications globally.</li> |
|---|
| 18 | </ul> |
|---|
| 19 | |
|---|
| 20 | <p>A Loader element MAY be nested inside a <a href="context.html">Context</a> |
|---|
| 21 | component. If it is not included, a default Loader configuration will be |
|---|
| 22 | created automatically, which is sufficient for most requirements.</p> |
|---|
| 23 | |
|---|
| 24 | <p>For a more in-depth description of the class loader hierarchy |
|---|
| 25 | that is implemented by Catalina, see <a href="../class-loader-howto.html">the ClassLoader HowTo</a>.</p> |
|---|
| 26 | |
|---|
| 27 | <blockquote><em> |
|---|
| 28 | <p>The description below uses the variable name $CATALINA_BASE to refer the |
|---|
| 29 | base directory against which most relative paths are resolved. If you have |
|---|
| 30 | not configured Tomcat 6 for multiple instances by setting a CATALINA_BASE |
|---|
| 31 | directory, then $CATALINA_BASE will be set to the value of $CATALINA_HOME, |
|---|
| 32 | the directory into which you have installed Tomcat 6.</p> |
|---|
| 33 | </em></blockquote> |
|---|
| 34 | |
|---|
| 35 | </blockquote></td></tr></table><table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#525D76"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Attributes"><strong>Attributes</strong></a></font></td></tr><tr><td><blockquote> |
|---|
| 36 | |
|---|
| 37 | <table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#828DA6"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Common Attributes"><strong>Common Attributes</strong></a></font></td></tr><tr><td><blockquote> |
|---|
| 38 | |
|---|
| 39 | <p>All implementations of <strong>Loader</strong> |
|---|
| 40 | support the following attributes:</p> |
|---|
| 41 | |
|---|
| 42 | <table cellpadding="5" border="1"><tr><th bgcolor="#023264" width="15%"><font color="#ffffff">Attribute</font></th><th bgcolor="#023264" width="85%"><font color="#ffffff">Description</font></th></tr><tr><td valign="center" align="left"><code>className</code></td><td valign="center" align="left"> |
|---|
| 43 | <p>Java class name of the implementation to use. This class must |
|---|
| 44 | implement the <code>org.apache.catalina.Loader</code> interface. |
|---|
| 45 | If not specified, the standard value (defined below) will be used.</p> |
|---|
| 46 | </td></tr><tr><td valign="center" align="left"><code>delegate</code></td><td valign="center" align="left"> |
|---|
| 47 | <p>Set to <code>true</code> if you want the class loader to follow |
|---|
| 48 | the standard Java2 delegation model, and attempt to load classes from |
|---|
| 49 | parent class loaders <strong>before</strong> looking inside the web |
|---|
| 50 | application. Set to <code>false</code> (the default) to have the |
|---|
| 51 | class loader look inside the web application first, before asking |
|---|
| 52 | parent class loaders to find requested classes or resources.</p> |
|---|
| 53 | </td></tr><tr><td valign="center" align="left"><code>reloadable</code></td><td valign="center" align="left"> |
|---|
| 54 | <p>Set to <code>true</code> if you want Catalina to monitor classes in |
|---|
| 55 | <code>/WEB-INF/classes/</code> and <code>/WEB-INF/lib</code> for |
|---|
| 56 | changes, and automatically reload the web application if a change |
|---|
| 57 | is detected. This feature is very useful during application |
|---|
| 58 | development, but it requires significant runtime overhead and is |
|---|
| 59 | not recommended for use on deployed production applications. You |
|---|
| 60 | can use the <a href="../manager-howto.html">Manager</a> web |
|---|
| 61 | application, however, to trigger reloads of deployed applications |
|---|
| 62 | on demand.</p> |
|---|
| 63 | |
|---|
| 64 | <p><strong>NOTE</strong> - The value for this property will be |
|---|
| 65 | inherited from the <code>reloadable</code> attribute you set on |
|---|
| 66 | the surrounding <a href="context.html">Context</a> component, |
|---|
| 67 | and any value you explicitly set here will be replaced.</p> |
|---|
| 68 | </td></tr></table> |
|---|
| 69 | |
|---|
| 70 | </blockquote></td></tr></table> |
|---|
| 71 | |
|---|
| 72 | |
|---|
| 73 | <table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#828DA6"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Standard Implementation"><strong>Standard Implementation</strong></a></font></td></tr><tr><td><blockquote> |
|---|
| 74 | |
|---|
| 75 | <p>The standard implementation of <strong>Loader</strong> is |
|---|
| 76 | <strong>org.apache.catalina.loader.WebappLoader</strong>. |
|---|
| 77 | It supports the following additional attributes (in addition to the |
|---|
| 78 | common attributes listed above):</p> |
|---|
| 79 | |
|---|
| 80 | <table cellpadding="5" border="1"><tr><th bgcolor="#023264" width="15%"><font color="#ffffff">Attribute</font></th><th bgcolor="#023264" width="85%"><font color="#ffffff">Description</font></th></tr><tr><td valign="center" align="left"><code>loaderClass</code></td><td valign="center" align="left"> |
|---|
| 81 | <p>Java class name of the <code>java.lang.ClassLoader</code> |
|---|
| 82 | implementation class to use. If not specified, the default value is |
|---|
| 83 | <code>org.apache.catalina.loader.WebappClassLoader</code>.</p> |
|---|
| 84 | </td></tr></table> |
|---|
| 85 | |
|---|
| 86 | </blockquote></td></tr></table> |
|---|
| 87 | |
|---|
| 88 | |
|---|
| 89 | </blockquote></td></tr></table><table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#525D76"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Nested Components"><strong>Nested Components</strong></a></font></td></tr><tr><td><blockquote> |
|---|
| 90 | |
|---|
| 91 | <p>No components may be nested inside a <strong>Loader</strong> element.</p> |
|---|
| 92 | |
|---|
| 93 | </blockquote></td></tr></table><table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#525D76"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Special Features"><strong>Special Features</strong></a></font></td></tr><tr><td><blockquote> |
|---|
| 94 | |
|---|
| 95 | <table cellpadding="2" cellspacing="0" border="0"><tr><td bgcolor="#828DA6"><font face="arial,helvetica.sanserif" color="#ffffff"><a name="Logging"><strong>Logging</strong></a></font></td></tr><tr><td><blockquote> |
|---|
| 96 | |
|---|
| 97 | <p>A loader is associated with the log category based on its classname.</p> |
|---|
| 98 | |
|---|
| 99 | </blockquote></td></tr></table> |
|---|
| 100 | |
|---|
| 101 | </blockquote></td></tr></table></td></tr><!--FOOTER SEPARATOR--><tr><td colspan="2"><hr size="1" noshade></td></tr><!--PAGE FOOTER--><tr><td colspan="2"><div align="center"><font size="-1" color="#525D76"><em> |
|---|
| 102 | Copyright © 1999-2008, Apache Software Foundation |
|---|
| 103 | </em></font></div></td></tr></table></body></html> |
|---|
