Installing and Running Tomcat (MCS-270, Spring 2006)

Introduction

The first part of this lab involves installing your own copy of tomcat. Having your own copy of tomcat is useful since it allows you to independently develop applications. It also allows you to view the error logs for the applications you are developing; believe me, this will happen often.

Up until last year, we raised each student's disk quota, since tomcat is fairly large (somewhere in excess of 20 megabytes). After discussing this with one of the sysadmins downstairs, we decided not to do that this year, since everyone's quota is already at 125 megabytes, which should be more than adequate. If you hit a wall in terms of disk usage, let me know, and we'll see what we can do.

Installing and launching Tomcat

Extract your version of tomcat: Switch to your home directory, since that is where you should install tomcat. (You could put it elsewhere, but it will be better if you put it there, since it will then be easier for me to describe how to do this, and also to check for installation errors.) From your home directory, issue the following command:
```
    tar xfz ~karl/public/270/apache-tomcat-5.5.15.tar.gz
```
This should create the directory apache-tomcat-5.5.15/
To save time typing, put a symlink from tomcat in your home directory to the installation directory, apache-tomcat-5.5.15. (This should be done before changing directory.)
```
    ln -s `pwd`/apache-tomcat-5.5.15 ~/tomcat
```

Create the directory where jsp applications will be stored:

   mkdir ~/webapps
   mkdir ~/webapps/WEB-INF
   mkdir ~/webapps/WEB-INF/classes
   mkdir ~/webapps/WEB-INF/lib

Create a symlink in ~/tomcat/webapps/ to your webapps directory. This symlink will be of the form webapps-username; for example, mine is webapps-karl:
```
    ln -s ~/webapps ~/tomcat/webapps/webapps-`whoami`
```
Set environment variable for JAVA_HOME to /usr/java/current In a csh shell, use
```
    setenv JAVA_HOME /usr/java/current
```
In the bash shell, use
```
    export JAVA_HOME=/usr/java/current
```
You'll probably want to also set up JAVA_HOME or other environment variables automatically when you log in by adding the above line(s) in your .cshrc file and/or .bashrc file respectively, depending on whether you use csh and/or bash.
Start up tomcat:
```
    ~/tomcat/bin/startup.sh
```
NOTE: You should shutdown tomcat when you are done using
```
    ~/tomcat/bin/shutdown.sh
```
This frees up the 8080 port for a classmate. Also, you can make starting up, shutting down, and restarting tomcat easier by putting the following aliases in .cshrc:
```
    alias sta ~/tomcat/bin/startup.sh
    alias shu ~/tomcat/bin/shutdown.sh
    alias restart ~/tomcat/bin/shutdown.sh \; ~/tomcat/bin/startup.sh
```
Then, you will only need to type sta, shu, or restart to have the desired effect.
Copy my jsp work directory: Go to the directory where you want to do your jsp programming and issue the following command:
```
    cp -r ~karl/public/270/jsp .
```
This will create a directory called jsp which currently contains two sub-directories, one called called hello, which contains the Hello World application I described in class yesterday, and another called num (which is described later).
Install the Hello World application: Move to the jsp/hello directory and type the following command:
```
    make
```
This will use the GNUMakefile in that directory to install the file hello.jsp in the directory ~/webapps.
Launch the Hello World application: You can view sample jsp page by entering something like this in the URL:
```
    http://localhost:8080/webapps-username/hello.jsp
```
Check-off: Show me that you have successfully viewed this file.

Comments

You'll want to launch tomcat yourself rather than using the tomcat process running on mcs-jsp.gac.edu for several reasons:

You can view the log files to help diagnose problems. They are in:
```
    ~/tomcat/logs/
```
In particular,
```
    ~/tomcat/logs/catalina.out
```
will record output sent to System.out

You can also view the java code generated by tomcat in

   ~/tomcat/work/Catalina/localhost/webapps-username/

You'll be able to restart tomcat when you create new webapps. For efficiency reasons, tomcat doesn't go hunting for them on every query.

Where to put files

~/webapps/ is for your jsp files. You may choose to save them in a subdirectory to keep webapps/ clean, such as jsp. Depending on whether you choose to make a jsp directory, the URL to mywebpage.jsp would be
```
    http://localhost:8080/webapps-username/mywebpage.jsp
```
or
```
    http://localhost:8080/webapps-username/jsp/mywebpage.jsp
```
~/webapps/WEB-INF/classes/ is where you'll save compiled .class files. Note that class files must be part of packages, so will be in subdirectories of classes. For example, the class edu.gustavus.karl.MyClass will be in webapps/WEB-INF/classes/edu/gustavus/karl/MyClass.class
~/webapps/WEB-INF/lib/ is for jar files.

Restarting tomcat

When you create a new web application, you may need to restart tomcat for it to see the new application. Do so by

    ~/tomcat/bin/shutdown.sh ; ~/tomcat/bin/startup.sh

It'll take about 30 seconds to a minute to restart. If you did the aliases I described above, you will only need to type shu.

Ending tomcat

Please end your tomcat process before you leave in order to make the machine available for the next user. The correct way is to type

    ~/tomcat/bin/shutdown.sh

or you can choose the brutal but expedient,

    killall java

This will kill all java processes you have launched, including tomcat.

Installing class files

During development, it's convenient to keep all files in one directory. But, as mentioned before, for deployment, class files need to be in a separate directory.

I've also placed a directory num which contains an application I will explain on Thursday. If you go to that directory and type ls, you should see 3 files; please read through them. Observe that the GNUmakefile contains information (which you can edit) about where the webapp files will be deployed.
Install the webapp by editing the line of GNUmakefile to your liking and then type
```
    make
```
Load numguess.jsp in your browser just as you did for hello.jsp. (You may need to restart tomcat if tomcat doesn't find it.)
Now edit numguess.jsp and NumberGuessBean.java to try some experiments. For example, you could, for instance, make the game easy hard-coding your favorite number as the answer. You could also put change the Bean so that it outputs the guess by placing a line like
```
   System.out.println("User guessed: " + guess)
```
in an appropriate place in NumberGuessBean.java. After running the app, you can inspect the catalina.out file to trace the guesses.
Try playing with other sample apps in ~/tomcat/webapps/examples/. You should make copies of the into source directories, like my num directory, copy the GNUmakefile and play.
One last note: In order to install any code which uses the jdbc with mysql, you'll need to install the appropriate jar file. You may wish to take care of that now:
```
   cp -r ~karl/public/270/mysql.jar ~/tomcat/common/lib
```