Also in Using Tomcat:
This article, in which we examine issues specific to Tomcat, is the second in our series on the Jakarta-Tomcat server. In this article we will discuss
Before performing the tasks outlined by this article you will need to download the items listed in the Table 1.
Table 1. Requirements
|Tomcat 4.0 beta 1||http://jakarta.apache.org/|
|JDK 1.3 Standard Edition|
For this article we will be using the latest versions of the tools listed above.
In this article we will be installing Tomcat as a stand-alone server. This means that Tomcat will service all requests, including static content, JSPs, and servlets.
To configure Tomcat as a stand-alone server you will need to download the Tomcat 4.0 beta 1 and the JDK 1.3 Standard Edition from the locations listed above. You should choose the appropriate downloads based on your OS. We will be covering the steps involved in installing to both NT/2000 and Linux.
Installing to Windows NT/2000
The first installation we will be performing is to Windows NT/2000. The first thing you need to do is install the JDK, following its installation instructions. For this article I am installing the JDK to drive D:, therefore my
JAVA_HOME directory is
Now you need to extract the Tomcat server. Again, I am installing
to drive D:, which will make my
After you have extracted Tomcat, the next step is putting your JDK
CLASSPATH and setting the
TOMCAT_HOME environment variable. To do this under
NT/2000, you must
Open the NT/2000 Control Panel. You should see an image similar to Figure 1.
Start the NT/2000 System Application and select the Advanced tab. You should see a screen similar to Figure 2.
Select the Environment Variables button. You will see a screen similar to Figure 3.
Select the New button on the System Variables section of the Environment Variables dialog. Add a JAVA_HOME variable and set its value to the location of your JDK installation. Figure 4 shows the settings associated with my installation.
Repeat Step 4 using
TOMCAT_HOME for the variable
name and the location of your Tomcat installation as the value. For
my installation I am setting the value to
That's all there is to it. You should skip the following section "Installing to Linux" and move on to "Testing You Tomcat Installation."
Installing to Linux
The installation is much simpler on a Linux than a Windows machine. The first thing you need to do is install the JDK. For our purposes, we will assume that the JDK will be installed to
After you have the JDK installed, you need to set the
JAVA_HOME environment variable. To do this under Linux,
find your shell in Table 2 and type the matching command. You will
need to replace
/bob/java with the root location of your
Table 2. Java Environment Settings
You should add the location of the Java interpreter to your
PATH environment variable.
You now need to extract the Tomcat server to a directory of your
choosing. This directory will become the
directory. For this installation, we will assume that Tomcat will be
The last step is to set the
variable. To do this under Linux, find your shell in Table 3 and type
the matching command. You will need to replace
the name of the directory located directly above your Tomcat
Table 3. Tomcat Environment Settings
To test the Tomcat installation, first start the Tomcat server. Table 4 contains the startup and shutdown commands for each OS.
Table 4. Tomcat Startup/Shutdown Commands
Once Tomcat has started, point your browser at
You should see a page similar to Figure 5.
If you would like to have all requests serviced on the default HTTP
port of 80, instead of port 8080, you will need to make
the following change to the
file and restart Tomcat.
<!-- Define a non-SSL HTTP/1.1 Connector on port 8080 -->
port="8080" minProcessors="5" maxProcessors="75"
<!-- Define a non-SSL HTTP/1.1 Connector on port 80 -->
port="80" minProcessors="5" maxProcessors="75"
Now point your browser at
and you'll see results similar to those in Figure 5.
The next step is to verify the installation of your JDK, which is done by executing one of the JSP examples provided with the Tomcat server. At the page shown in Figure 5, choose JSP Examples. You should see a page similar to Figure 6.
Now choose the JSP example Date and select the Execute link. If everything was installed properly you should see a page similar to Figure 7 (of course with a different date).
If you do not see the previous page, then you need to make sure
that the location of your
JAVA_HOME environment variable
matches the location of your JDK installation.
Once Tomcat is installed and running, let's look at the steps
necessary to deploy a web application. To deploy a web app, we need
to examine the directory structure of Tomcat. Table 5 describes the
directories that make up a Tomcat installation. It is assumed that the
TOMCAT_HOME precedes each of these
And because we are using a beta release of Tomcat, these directories could change without notice.
Table 5. The Tomcat Directory Structure
This directory contains the startup and shutdown scripts for both Windows and Linux.
This directory contains the main
configuration files for Tomcat. The two most important are the
This directory contains the Tomcat Java Archive files.
This directory contains Java Archive files that Tomcat is dependent upon.
This directory contains Tomcat's log files.
This directory contains the source code used by the Tomcat server. Once Tomcat is released, it will probably contain interfaces and abstract classes only.
All web applications are deployed in this directory; it contains the WAR file.
This is the directory in which Tomcat will place all servlets that are generated from JSPs. If you want to see exactly how a particular JSP is interpreted, look in this directory.
We will examine most of these directories in future articles. For
the remainder of this article we're interested in the
/webapps directory, which is where all of our WAR files
will be deployed.
In our last article we described the contents of a web application and how they are packaged. Once you have a WAR file, containing your web application, deploying web applications to Tomcat is a simple two-step process.
Steps Involved in Deploying a Web Application to Tomcat
Copy your WAR file to the
Add a new Context entry to the
TOMCAT_HOME/conf/server.xml file, setting the values for
the path and docBase to the name of your web application.
<Context path="/onjava" docBase="onjava" debug="0"
Restart Tomcat after completing these steps. Your application should now be running.
The previously described application can be accessed by pointing your browser at
If you look at the
TOMCAT_HOME/webapps directory, you
will see a new directory matching the name of your WAR file. This is
where your working web application now exists. When Tomcat starts it
will extract all WAR files that have been recently placed into the
In the next article we will learn how to add Servlets, JSPs, and custom tag libraries to a web application. We will also discuss the relationship between a web application and its ServletContext.
James Goodwill is the co-Founder of Virtuas Solutions, LLC, a Colorado-based software consultancy.
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