Tomcat (MCS-270, Spring 2005)

Introduction

Each of your home directory's quotas has been increased to accomodate a copy of tomcat.

Installing and launching Tomcat

Extract the customized version of tomcat. Switch to the directory in which you wish tomcat to be saved. I'll assume that's in your home directory, but you could put it anywhere.
```
    tar xfz ~wolfe/public/270/tomcat.tgz
```
This should create the directory jakarta-tomcat-4.1.29/
To save time typing, put a symlink from tomcat in your home directory to the installation directory, jakarta-tomcat-4.1.29. (This should be done before changing directory.)
```
    ln -s `pwd`/jakarta-tomcat-4.1.29 ~/tomcat
```
Create a sym link in ~/tomcat/webapps/ to your webapps directory. On mcs-jsp, I named the symlinks webapps-username, so mine is webapps-wolfe.
```
    cd ~/tomcat/webapps
    ln -s ~/webapps ~/tomcat/webapps/webapps-username
```

Create your directory where jsp applications will be stored:

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

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.
Create a sample jsp page in your webapps directory such as hello.jsp. View sample jsp page by entering something like this in the URL:
```
    http://localhost:8080/webapps-username/hello.jsp
```
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/Standalone/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.wolfe.MyClass will be in webapps/WEB-INF/classes/edu/gustavus/wolfe/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.

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 placed NumberGuessBean.java and numguess.jsp (distributed with tomcat) in a single directory along with a Makefile which knows how to compile them. To install, copy the directory to anywhere in your home directory:
```
    cd directory-name-of-your-choosing
    cp -r ~wolfe/public/270/jspapps/num/ .
    cd ./num
    ls -l
```
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 class files. You may wish to take care of that now:
```
   cp -r ~wolfe/public/270/java/com/ ~/tomcat/shared/classes/
```
These are class files which are shared among apps.