| <html><head><META http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><title>Application Developer's Guide (6.0.39) - Source Organization</title><meta name="author" content="Craig R. McClanahan"><style type="text/css" media="print"> | |
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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 6.0</font></h1><font face="arial,helvetica,sanserif">Version 6.0.39, Jan 27 2014</font></td><td><!--APACHE LOGO--><a href="http://www.apache.org/"><img src="../images/asf-logo.gif" align="right" alt="Apache Logo" border="0"></a></td></tr></table><table border="0" width="100%" cellspacing="4"><!--HEADER SEPARATOR--><tr><td colspan="2"><hr noshade="noshade" size="1"></td></tr><tr><!--LEFT SIDE NAVIGATION--><td width="20%" valign="top" nowrap="nowrap" class="noPrint"><p><strong>Links</strong></p><ul><li><a href="../index.html">Docs Home</a></li></ul><p><strong>Contents</strong></p><ul><li><a href="index.html">Contents</a></li><li><a href="introduction.html">Introduction</a></li><li><a href="installation.html">Installation</a></li><li><a href="deployment.html">Deployment</a></li><li><a href="source.html">Source Code</a></li><li><a href="processes.html">Processes</a></li><li><a href="sample/">Example App</a></li></ul></td><!--RIGHT SIDE MAIN BODY--><td width="80%" valign="top" align="left" id="mainBody"><h1>Application Developer's Guide</h1><h2>Source Organization</h2><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Table of Contents"><!--()--></a><a name="Table_of_Contents"><strong>Table of Contents</strong></a></font></td></tr><tr><td><blockquote> | |
| <ul><li><a href="#Directory_Structure">Directory Structure</a><ol><li><a href="#External_Dependencies">External Dependencies</a></li></ol></li><li><a href="#Source_Code_Control">Source Code Control</a></li><li><a href="#BUILD.XML_Configuration_File">BUILD.XML Configuration File</a></li></ul> | |
| </blockquote></td></tr></table><table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#525D76"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="Directory Structure"><!--()--></a><a name="Directory_Structure"><strong>Directory Structure</strong></a></font></td></tr><tr><td><blockquote> | |
| <blockquote><em> | |
| <p>The description below uses the variable name $CATALINA_BASE to refer the | |
| base directory against which most relative paths are resolved. If you have | |
| not configured Tomcat 6 for multiple instances by setting a CATALINA_BASE | |
| directory, then $CATALINA_BASE will be set to the value of $CATALINA_HOME, | |
| the directory into which you have installed Tomcat 6.</p> | |
| </em></blockquote> | |
| <p>A key recommendation of this manual is to separate the directory | |
| hierarchy containing your source code (described in this section) from | |
| the directory hierarchy containing your deployable application | |
| (described in the preceding section). Maintaining this separation has | |
| the following advantages:</p> | |
| <ul> | |
| <li>The contents of the source directories can be more easily administered, | |
| moved, and backed up if the "executable" version of the application | |
| is not intermixed. | |
| <br><br></li> | |
| <li>Source code control is easier to manage on directories that contain | |
| only source files. | |
| <br><br></li> | |
| <li>The files that make up an installable distribution of your | |
| application are much easier to select when the deployment | |
| hierarchy is separate.</li> | |
| </ul> | |
| <p>As we will see, the <code>ant</code> development tool makes the creation | |
| and processing of such directory hierarchies nearly painless.</p> | |
| <p>The actual directory and file hierarchy used to contain the source code | |
| of an application can be pretty much anything you like. However, the | |
| following organization has proven to be quite generally applicable, and is | |
| expected by the example <code>build.xml</code> configuration file that | |
| is discussed below. All of these components exist under a top level | |
| <em>project source directory</em> for your application:</p> | |
| <ul> | |
| <li><strong>docs/</strong> - Documentation for your application, in whatever | |
| format your development team is using.<br><br></li> | |
| <li><strong>src/</strong> - Java source files that generate the servlets, | |
| beans, and other Java classes that are unique to your application. | |
| If your source code is organized in packages (<strong>highly</strong> | |
| recommended), the package hierarchy should be reflected as a directory | |
| structure underneath this directory.<br><br></li> | |
| <li><strong>web/</strong> - The static content of your web site (HTML pages, | |
| JSP pages, JavaScript files, CSS stylesheet files, and images) that will | |
| be accessible to application clients. This directory will be the | |
| <em>document root</em> of your web application, and any subdirectory | |
| structure found here will be reflected in the request URIs required to | |
| access those files.<br><br></li> | |
| <li><strong>web/WEB-INF/</strong> - The special configuration files required | |
| for your application, including the web application deployment descriptor | |
| (<code>web.xml</code>, defined in the | |
| <a href="http://wiki.apache.org/tomcat/Specifications">Servlet Specification</a>), | |
| tag library descriptors for custom tag libraries | |
| you have created, and other resource files you wish to include within | |
| your web application. Even though this directory appears to be a | |
| subdirectory of your <em>document root</em>, the Servlet Specification | |
| prohibits serving the contents of this directory (or any file it contains) | |
| directly to a client request. Therefore, this is a good place to store | |
| configuration information that is sensitive (such as database connection | |
| usernames and passwords), but is required for your application to | |
| operate successfully.</li> | |
| </ul> | |
| <p>During the development process, two additional directories will be | |
| created on a temporary basis:</p> | |
| <ul> | |
| <li><strong>build/</strong> - When you execute a default build | |
| (<code>ant</code>), this directory will contain an exact image | |
| of the files in the web application archive for this application. | |
| Tomcat 6 allows you to deploy an application in an unpacked | |
| directory like this, either by copying it to the | |
| <code>$CATALINA_BASE/webapps</code> directory, or by <em>installing</em> | |
| it via the "Manager" web application. The latter approach is very | |
| useful during development, and will be illustrated below. | |
| <br><br></li> | |
| <li><strong>dist/</strong> - When you execute the <code>ant dist</code> | |
| target, this directory will be created. It will create an exact image | |
| of the binary distribution for your web application, including an license | |
| information, documentation, and README files that you have prepared.</li> | |
| </ul> | |
| <p>Note that these two directories should <strong>NOT</strong> be archived in | |
| your source code control system, because they are deleted and recreated (from | |
| scratch) as needed during development. For that reason, you should not edit | |
| any source files in these directories if you want to maintain a permanent | |
| record of the changes, because the changes will be lost the next time that a | |
| build is performed.</p> | |
| <table border="0" cellspacing="0" cellpadding="2"><tr><td bgcolor="#828DA6"><font color="#ffffff" face="arial,helvetica.sanserif"><a name="External Dependencies"><!--()--></a><a name="External_Dependencies"><strong>External Dependencies</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>What do you do if your application requires JAR files (or other | |
| resources) from external projects or packages? A common example is that | |
| you need to include a JDBC driver in your web application, in order to | |
| operate.</p> | |
| <p>Different developers take different approaches to this problem. | |
| Some will encourage checking a copy of the JAR files you depend on into | |
| the source code control archives for every application that requires those | |
| JAR files. However, this can cause significant management issues when you | |
| use the same JAR in many applications - particular when faced with a need | |
| to upgrade to a different version of that JAR file.</p> | |
| <p>Therefore, this manual recommends that you <strong>NOT</strong> store | |
| a copy of the packages you depend on inside the source control archives | |
| of your applications. Instead, the external dependencies should be | |
| integrated as part of the process of <strong>building</strong> your | |
| application. In that way, you can always pick up the appropriate version | |
| of the JAR files from wherever your development system administrator has | |
| installed them, without having to worry about updating your application | |
| every time the version of the dependent JAR file is changed.</p> | |
| <p>In the example Ant <code>build.xml</code> file, we will demonstrate | |
| how to define <em>build properties</em> that let you configure the locations | |
| of the files to be copied, without having to modify <code>build.xml</code> | |
| when these files change. The build properties used by a particular | |
| developer can be customized on a per-application basis, or defaulted to | |
| "standard" build properties stored in the developer's home directory.</p> | |
| <p>In many cases, your development system administrator will have already | |
| installed the required JAR files into the <code>lib</code> directory of Tomcat. | |
| If this has been done, you need | |
| to take no actions at all - the example <code>build.xml</code> file | |
| automatically constructs a compile classpath that includes these files.</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="Source Code Control"><!--()--></a><a name="Source_Code_Control"><strong>Source Code Control</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>As mentioned earlier, it is highly recommended that you place all of the | |
| source files that comprise your application under the management of a | |
| source code control system like the Concurrent Version System (CVS). If you | |
| elect to do this, every directory and file in the source hierarchy should be | |
| registered and saved -- but none of the generated files. If you register | |
| binary format files (such as images or JAR libraries), be sure to indicate | |
| this to your source code control system.</p> | |
| <p>We recommended (in the previous section) that you should not store the | |
| contents of the <code>build/</code> and <code>dist/</code> directories | |
| created by your development process in the source code control system. An | |
| easy way to tell CVS to ignore these directories is to create a file named | |
| <code>.cvsignore</code> (note the leading period) in your top-level source | |
| directory, with the following contents:</p> | |
| <div align="left"><table cellspacing="4" cellpadding="0" border="0"><tr><td bgcolor="#023264" width="1" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" width="1" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr><tr><td bgcolor="#023264" width="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#ffffff" height="1"><pre> | |
| build | |
| dist | |
| build.properties | |
| </pre></td><td bgcolor="#023264" width="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr><tr><td bgcolor="#023264" width="1" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" width="1" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr></table></div> | |
| <p>The reason for mentioning <code>build.properties</code> here will be | |
| explained in the <a href="processes.html">Processes</a> section.</p> | |
| <p>Detailed instructions for your source code control environment are beyond | |
| the scope of this manual. However, the following steps are followed when | |
| using a command-line CVS client:</p> | |
| <ul> | |
| <li>To refresh the state of your source code to that stored in the | |
| the source repository, go to your project source directory, and | |
| execute <code>cvs update -dP</code>. | |
| <br><br></li> | |
| <li>When you create a new subdirectory in the source code hierarchy, register | |
| it in CVS with a command like <code>cvs add {subdirname}</code>. | |
| <br><br></li> | |
| <li>When you first create a new source code file, navigate to the directory | |
| that contains it, and register the new file with a command like | |
| <code>cvs add {filename}</code>. | |
| <br><br></li> | |
| <li>If you no longer need a particular source code file, navigate to the | |
| containing directory and remove the file. Then, deregister it in CVS | |
| with a command like <code>cvs remove {filename}</code>. | |
| <br><br></li> | |
| <li>While you are creating, modifying, and deleting source files, changes | |
| are not yet reflected in the server repository. To save your changes in | |
| their current state, go to the project source directory | |
| and execute <code>cvs commit</code>. You will be asked to write a brief | |
| description of the changes you have just completed, which will be stored | |
| with the new version of any updated source file.</li> | |
| </ul> | |
| <p>CVS, like other source code control systems, has many additional features | |
| (such as the ability to tag the files that made up a particular release, and | |
| support for multiple development branches that can later be merged). See the | |
| links and references in the <a href="introduction.html">Introduction</a> for | |
| more information.</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="BUILD.XML Configuration File"><!--()--></a><a name="BUILD.XML_Configuration_File"><strong>BUILD.XML Configuration File</strong></a></font></td></tr><tr><td><blockquote> | |
| <p>We will be using the <strong>ant</strong> tool to manage the compilation of | |
| our Java source code files, and creation of the deployment hierarchy. Ant | |
| operates under the control of a build file, normally called | |
| <code>build.xml</code>, that defines the processing steps required. This | |
| file is stored in the top-level directory of your source code hierarchy, and | |
| should be checked in to your source code control system.</p> | |
| <p>Like a Makefile, the <code>build.xml</code> file provides several | |
| "targets" that support optional development activities (such as creating | |
| the associated Javadoc documentation, erasing the deployment home directory | |
| so you can build your project from scratch, or creating the web application | |
| archive file so you can distribute your application. A well-constructed | |
| <code>build.xml</code> file will contain internal documentation describing | |
| the targets that are designed for use by the developer, versus those targets | |
| used internally. To ask Ant to display the project documentation, change to | |
| the directory containing the <code>build.xml</code> file and type:</p> | |
| <div align="left"><table cellspacing="4" cellpadding="0" border="0"><tr><td bgcolor="#023264" width="1" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" width="1" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr><tr><td bgcolor="#023264" width="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#ffffff" height="1"><pre> | |
| ant -projecthelp | |
| </pre></td><td bgcolor="#023264" width="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr><tr><td bgcolor="#023264" width="1" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td><td bgcolor="#023264" width="1" height="1"><img src="../images/void.gif" alt="" width="1" height="1" vspace="0" hspace="0" border="0"></td></tr></table></div> | |
| <p>To give you a head start, a <a href="build.xml.txt">basic build.xml file</a> | |
| is provided that you can customize and install in the project source directory | |
| for your application. This file includes comments that describe the various | |
| targets that can be executed. Briefly, the following targets are generally | |
| provided:</p> | |
| <ul> | |
| <li><strong>clean</strong> - This target deletes any existing | |
| <code>build</code> and <code>dist</code> directories, so that they | |
| can be reconstructed from scratch. This allows you to guarantee that | |
| you have not made source code modifications that will result in | |
| problems at runtime due to not recompiling all affected classes. | |
| <br><br></li> | |
| <li><strong>compile</strong> - This target is used to compile any source code | |
| that has been changed since the last time compilation took place. The | |
| resulting class files are created in the <code>WEB-INF/classes</code> | |
| subdirectory of your <code>build</code> directory, exactly where the | |
| structure of a web application requires them to be. Because | |
| this command is executed so often during development, it is normally | |
| made the "default" target so that a simple <code>ant</code> command will | |
| execute it. | |
| <br><br></li> | |
| <li><strong>all</strong> - This target is a short cut for running the | |
| <code>clean</code> target, followed by the <code>compile</code> target. | |
| Thus, it guarantees that you will recompile the entire application, to | |
| ensure that you have not unknowingly introduced any incompatible changes. | |
| <br><br></li> | |
| <li><strong>javadoc</strong> - This target creates Javadoc API documentation | |
| for the Java classes in this web application. The example | |
| <code>build.xml</code> file assumes you want to include the API | |
| documentation with your app distribution, so it generates the docs | |
| in a subdirectory of the <code>dist</code> directory. Because you normally | |
| do not need to generate the Javadocs on every compilation, this target is | |
| usually a dependency of the <code>dist</code> target, but not of the | |
| <code>compile</code> target. | |
| <br><br></li> | |
| <li><strong>dist</strong> - This target creates a distribution directory for | |
| your application, including any required documentation, the Javadocs for | |
| your Java classes, and a web application archive (WAR) file that will be | |
| delivered to system administrators who wish to install your application. | |
| Because this target also depends on the <code>deploy</code> target, the | |
| web application archive will have also picked up any external dependencies | |
| that were included at deployment time.</li> | |
| </ul> | |
| <p>For interactive development and testing of your web application using | |
| Tomcat 6, the following additional targets are defined:</p> | |
| <ul> | |
| <li><strong>install</strong> - Tell the currently running Tomcat 6 to make | |
| the application you are developing immediately available for execution | |
| and testing. This action does not require Tomcat 6 to be restarted, but | |
| it is also not remembered after Tomcat is restarted the next time. | |
| <br><br></li> | |
| <li><strong>reload</strong> - Once the application is installed, you can | |
| continue to make changes and recompile using the <code>compile</code> | |
| target. Tomcat 6 will automatically recognize changes made to JSP pages, | |
| but not to servlet or JavaBean classes - this command will tell Tomcat | |
| to restart the currently installed application so that such changes are | |
| recognized. | |
| <br><br></li> | |
| <li><strong>remove</strong> - When you have completed your development and | |
| testing activities, you can optionally tell Tomcat 6 to remove this | |
| application from service. | |
| </li> | |
| </ul> | |
| <p>Using the development and testing targets requires some additional | |
| one-time setup that is described on the next page.</p> | |
| </blockquote></td></tr></table></td></tr><!--FOOTER SEPARATOR--><tr><td colspan="2"><hr noshade="noshade" size="1"></td></tr><!--PAGE FOOTER--><tr><td colspan="2"><div align="center"><font color="#525D76" size="-1"><em> | |
| Copyright © 1999-2014, Apache Software Foundation | |
| </em></font></div></td></tr></table></body></html> |