Lecture Notes for the T540 Networked Game Design with Java

T540 Spring Semester 2002

Lecture Notes Seventeen: WebApps. Server-side Java (II)

In which we finish the installation of Tomcat.

Here's my ~/.cshrc

#
#  .cshrc  - This file is executed whenever a C shell is started.
#

# set the umask, which controls the permissions on new files you create/
# 022 denies write access to other people, but not read access.
# 077 denies read and write access to other people.

umask 022

# Set the PATH.  You can put your own personal commands in 
# your ~/bin directory.
#
# Note for use on Solaris:
#       Put /usr/ucb in your path before /usr/bin and /usr/sbin if you
#           want the bsd-ish versions of things like ps and df.
#       Put /usr/bin and /usr/sbin in your path before /usr/ucb if you
#           want the svr4-ish versions of things like ps and df.
#	If you don't know the difference between bsd and svr4, then
#       it is safe to just leave this as it is.
#
set path = ( ~/bin \
        /home/user1/mysql/bin /usr/local/gnu/bin /usr/bin \
        /usr/local/bin /usr/sbin /usr/ucb \
	/usr/bin/X11 /usr/openwin/bin /usr/dt/bin /opt/SUNWspro/bin \
	/usr/ccs/bin /usr/local/gnu/bin )

# This prevents programs from dumping a large file called "core"
# in the current directory when they crash.
# If you really do want these core files, delete this line.
limit coredumpsize 0

# Tell the shell how many previous commands to remember.  You can
# view the previous commands using the history command
set history=20

# Uncomment the following line if you don't want ^D to log you out
#set ignoreeof

# The following lines tell the shell to periodically check for new mail
# and print the messages "You have new mail" when mail arrives.
# This is a separate sort of mail notification from that provided
# by biff (see your .login file) 
setenv MAIL /var/mail/$USER
set mail=$MAIL

# You may want to set the prompt to something fancy.  The following
# line puts the hostname, your username, and the current command number
# in the prompt
#set prompt="[`whoami`@`hostname`:\!] " 
set prompt="`hostname`% "

# Select a default printer.  Under Solaris, some programs use PRINTER
# and others use LPDEST.  See the printers man page (man printers)
# for a list of available printers.
#setenv PRINTER psburrow
#setenv LPDEST psburrow

# You can create aliases for common commands.  The following line
# makes lls equivalent to 'ls -l'
alias lls ls -l

       setenv JAVA_HOME   /l/jdk

       setenv CATALINA_HOME /u/dgerman/tomcat/jakarta-tomcat-4.0.3

       setenv CLASSPATH   .:$CATALINA_HOME/common/lib/servlet.jar

# setenv startTomcat $TOMCAT_HOME/bin/startup.sh
# setenv stopTomcat  $TOMCAT_HOME/bin/shutdown.sh

Please make sure yours is compatible.

Here's a description of the Tomcat folders.

$CATALINA_HOME/bin         # contains the startup/shutdown scripts 
              /conf        # main config files: server.xml, a global web.xml 
              /server      # contains Tomcat Java Archive files 
              /lib         # JAR files that the servlet engine depends on 
              /common/lib  # JAR files shared between Tomcat components (server.jar) 
              /jasper      # JAR files for Jasper the JSP compiler 
              /logs        # contains Tomcat's log files 
              /src         # source files 
              /webapps     # where all web applications are deployed 
              /work        # where all servlets generated from JSP are placed

Here's my server.xml

burrowww.cs.indiana.edu% pwd  
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.3/conf
burrowww.cs.indiana.edu% ls -ld server.xml
-rw-r--r--   1 dgerman  faculty      2846 Mar 21 12:59 server.xml
burrowww.cs.indiana.edu% cat server.xml

<Server port="36401" shutdown="SHUTDOWN" debug="0">


  <Service name="Tomcat-Standalone">

    <Connector className="org.apache.catalina.connector.http.HttpConnector"
               port="36400" minProcessors="5" maxProcessors="75"
               enableLookups="true" 
               acceptCount="10" debug="0" connectionTimeout="60000"/>

    <Engine name="Standalone" defaultHost="localhost" debug="0">

      <Logger className="org.apache.catalina.logger.FileLogger"
              prefix="catalina_log." suffix=".txt"
              timestamp="true"/>

      <Realm className="org.apache.catalina.realm.MemoryRealm" />

      <Host name="localhost" debug="0" appBase="webapps" unpackWARs="true">

        <Valve className="org.apache.catalina.valves.AccessLogValve"
                 directory="logs"  prefix="localhost_access_log." suffix=".txt"
                 pattern="common"/>

        <Logger className="org.apache.catalina.logger.FileLogger"
                 directory="logs"  prefix="localhost_log." suffix=".txt"
	        timestamp="true"/>

        <Context path="/manager" docBase="manager" 
         debug="0" privileged="true"/>

        <Context path="/one" docBase="one" debug="0" reloadable="true" /> 

        <Context path="/examples" docBase="examples" debug="0"
                 reloadable="true" crossContext="true">
          <Logger className="org.apache.catalina.logger.FileLogger"
                     prefix="localhost_examples_log." suffix=".txt"
        	  timestamp="true"/>
          <Ejb   name="ejb/EmplRecord" type="Entity"
                 home="com.wombat.empl.EmployeeRecordHome"
               remote="com.wombat.empl.EmployeeRecord"/>

          <Environment name="maxExemptions" type="java.lang.Integer"
                      value="15"/>
          <Parameter name="context.param.name" value="context.param.value"
                     override="false"/>
          <Resource name="jdbc/EmployeeAppDb" auth="SERVLET"
                    type="javax.sql.DataSource"/>
          <ResourceParams name="jdbc/EmployeeAppDb">
            <parameter><name>user</name><value>sa</value></parameter>
            <parameter><name>password</name><value></value></parameter>
            <parameter><name>driverClassName</name>
              <value>org.hsql.jdbcDriver</value></parameter>
            <parameter><name>driverName</name>
              <value>jdbc:HypersonicSQL:database</value></parameter>
          </ResourceParams>
          <Resource name="mail/Session" auth="Container"
                    type="javax.mail.Session"/>
          <ResourceParams name="mail/Session">
            <parameter>
              <name>mail.smtp.host</name>
              <value>localhost</value>
            </parameter>
          </ResourceParams>
        </Context>

      </Host>

    </Engine>

  </Service>



</Server>
burrowww.cs.indiana.edu%

I have already prepared a server.xml for each one of you.

Here's where you can find them:

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/public/tomcats
burrowww.cs.indiana.edu% ls -ld serv*
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.arausche
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.bkeese
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.cmfriend
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.cmhall
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.dgerman
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.dheald
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.gpolit
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.jchong
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.jffox
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.jfleetwo
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.jlbaumga
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.meblewis
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.ncincott
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.nlu
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.thom
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.thscott
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.wehrlich
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.wpernice
-rw-r--r--   1 dgerman  faculty      2774 Mar 21 11:00 server.xml.yinjin
burrowww.cs.indiana.edu%

Once you have server.xml place start Tomcat.

burrowww.cs.indiana.edu% ps -ef | grep dgerman
 dgerman 16121 18943  0 08:00:02 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 16119 18943  0 08:00:02 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 25984 23278  0 13:31:34 pts/42   0:00 grep dgerman
 dgerman 16101 18943  0 08:00:02 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 18943     1  0   Feb 12 ?        0:03 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 23278 23006  0 12:05:26 pts/42   0:00 -csh
 dgerman 16141 18943  0 08:00:03 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 24021 18943  0 12:06:30 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 24034 18943  0 12:06:31 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 16100 18943  0 08:00:02 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
burrowww.cs.indiana.edu% $CATALINA_HOME/bin/startup.sh
Using CATALINA_BASE:   /nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.3
Using CATALINA_HOME:   /nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.3
Using CATALINA_TMPDIR: /nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.3/temp
Using JAVA_HOME:       /l/jdk
burrowww.cs.indiana.edu% ps -ef | grep dgerman
 dgerman 16121 18943  0 08:00:02 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 26019     1  3 13:32:03 pts/42   0:05 /l/jdk/bin/../bin/sparc/native_threads/java -Djava.endorsed.dirs=/nfs/paca/home
 dgerman 16119 18943  0 08:00:02 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 16101 18943  0 08:00:02 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 18943     1  0   Feb 12 ?        0:03 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 23278 23006  0 12:05:26 pts/42   0:00 -csh
 dgerman 26033 23278  0 13:32:08 pts/42   0:00 grep dgerman
 dgerman 16141 18943  0 08:00:03 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 24021 18943  0 12:06:30 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 24034 18943  0 12:06:31 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
 dgerman 16100 18943  0 08:00:02 ?        0:00 /u/dgerman/apache/apache_1.3.22/bin/httpd
burrowww.cs.indiana.edu%

Then test it, here's the list of assigned ports:

201,BL,1255,36000,Last Name, First Name    ,dgerman      ,36400
201,BL,T540,36084,Baumgartner, Jason       ,jlbaumga     ,36402
201,BL,T540,36085,Cincotta, Nicholas       ,ncincott     ,36404
201,BL,T540,36086,Ehrlichman, Wesley       ,wehrlich     ,36406
201,BL,T540,36087,Fleetwood, Joshua        ,jfleetwo     ,36408
201,BL,T540,36088,Fox, John                ,jffox        ,36410
201,BL,T540,36089,Friend, Christopher      ,cmfriend     ,36412
201,BL,T540,36090,Hall, Christopher        ,cmhall       ,36414
201,BL,T540,36091,Heald, David             ,dheald       ,36416
201,BL,T540,36092,Keese, Brian             ,bkeese       ,36418
201,BL,T540,36093,Lewis, Megan             ,meblewis     ,36420
201,BL,T540,36094,Lu, Nan                  ,nlu          ,36422
201,BL,T540,36095,Polit, Gregory           ,gpolit       ,36424
201,BL,T540,36096,Rauscher, Andrew         ,arausche     ,36426
201,BL,T540,36097,Scott, Thomas            ,thscott      ,36428
201,BL,T540,36098,CHONG, Ji Young          ,jchong       ,36430
201,BL,T540,36099,Pernice, Wolfram         ,wpernice     ,36432
201,BL,T540,36109,Jin, Ying                ,yinjin       ,36434
201,BL,T540,36111,Gillespie, Thom          ,thom         ,36436

These ports are already written in the server.xml.username files.

Try the sample servlets, then the sample JSPs.

Then stop it, using:

$CATALINA_HOME/bin/shutdown.sh

Then start it again and let's develop a simple application.

The code we need to use is available in

/l/www/classes/a348/t540/lectures/servlets/jservlet2-examples/ch10

But first let's develop a simple application, call it one.

burrowww.cs.indiana.edu% mkdir one
burrowww.cs.indiana.edu% mkdir one/WEB-IN
burrowww.cs.indiana.edu% mkdir one/WEB-INF/classes
burrowww.cs.indiana.edu% mkdir one/WEB-INF/lib
burrowww.cs.indiana.edu% du -a one
1       one/WEB-INF/classes
1       one/WEB-INF/lib
3       one/WEB-INF
4       one
burrowww.cs.indiana.edu% cd one
burrowww.cs.indiana.edu% ls
WEB-INF
burrowww.cs.indiana.edu% cd WEB-INF
burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.3/webapps/one/WEB-INF
burrowww.cs.indiana.edu%

Then create your deployment descriptor web.xml as follows:

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.3/webapps/one/WEB-INF
burrowww.cs.indiana.edu% ls -l
total 3
drwxr-xr-x   2 dgerman  faculty       512 Mar 21 12:38 classes
drwxr-xr-x   2 dgerman  faculty       512 Mar 21 12:38 lib
-rw-r--r--   1 dgerman  faculty       340 Mar 21 12:46 web.xml
burrowww.cs.indiana.edu% cat web.xml
<?xml version="1.0" encoding="ISO-8859-1"?>

<!DOCTYPE web-app
    PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
    "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>


    <servlet>
        <servlet-name>howdy</servlet-name>
        <servlet-class>HelloWorld</servlet-class>
    </servlet>

</web-app>
burrowww.cs.indiana.edu%

Notice that examples also contain a WEB-INF/web.xml inside.

You now need to create a ServletContext in server.xml

<Context path="/one" docBase="one" debug="0" reloadable="true" />

This line should be added in between the manager and the examples contexts.

We now only need to write, compile, deploy the servlet.

burrowww.cs.indiana.edu% pwd
/nfs/paca/home/user1/dgerman/tomcat/jakarta-tomcat-4.0.3/webapps/one/WEB-INF/classes
burrowww.cs.indiana.edu% ls -ld Hell*.java
-rw-r--r--   1 dgerman  faculty       344 Mar 21 13:03 HelloWorld.java
burrowww.cs.indiana.edu% cat HelloWorld.java
import javax.servlet.*;
import java.io.*;

public class HelloWorld extends GenericServlet {
    int n; 
    public void service(ServletRequest  req,
                        ServletResponse resp) throws  ServletException,
                        IOException {
        n = n + 1; 
        resp.setContentType("text/html");
        PrintWriter out = resp.getWriter();
        out.println("Counter is: " + n);
    }
}
burrowww.cs.indiana.edu% javac Hell*.java
burrowww.cs.indiana.edu% ls -ld *
-rw-r--r--   1 dgerman  faculty       841 Mar 21 13:03 HelloWorld.class
-rw-r--r--   1 dgerman  faculty       344 Mar 21 13:03 HelloWorld.java
burrowww.cs.indiana.edu%

To access it, use this URL:

http://burrowww.cs.indiana.edu:364xx/one/servlet/howdy

The rest of the lecture/lab will be dedicated to chapter 10 from Jason Hunter's book.

That's basically a triple-chat application.

The code we need to use is available in

/l/www/classes/a348/t540/lectures/servlets/jservlet2-examples/ch10

Bibliography for Tomcat, servlets, and J2EE:

Also tutorials on-line at java.sun.com

Tutorial One (Web Services)
Tutorial Two (J2EE Tutorial)

Here now are the steps for the first part.

Say we keep everything in the same application, one.

Start by copying the entire code in the classes folder.

Now we need to identify three groups of files.

Group One: Client Side.

This is composed of the following three files:

DayTimeApplet.java
daytime.html
HttpMessage.java

These are to be placed under Tomcat's htdocs (webapps/ROOT/index.html).

Group Two: Server Side.

This is composed of the following two files:

DayTimeServlet.java
DaemonHttpServlet.java

These are to be placed in classes.

Compile them all.

Notice that we implement applet-servlet connections in five ways:

HTTP with plain text
HTTP with serialized objects
sockets with plain text
sockets with serialized objects
RMI (invoked on a remote object)

Also note that the applet and the servlet will both need a new port number.

That is needed for the socket communication.

The value is to be initialized as a parameter for both.

This will likely be shown next time.

Today we should implement the basic HTTP chat applet.

Last updated: Mar 21, 2002 by Adrian German for A348/A548