8/6/2019 Tomcat in MAC

http://slidepdf.com/reader/full/tomcat-in-mac 1/11

 

Search 

Advanced Search  

Log In | Not a Member?  Support 

ADC Home > Internet & Web > Java >

Java Servlets on Mac OS X

For the past few years, Java has been gaining popularity as a server-side programming language. Java’s object-

oriented nature and native network protocol handlers make it well suited for the web, especially for larger webapplications. There are several ways to use Java in combination with your web servers, but the most popularmethods involve Java servlets. Java servlets are extensions to a server, usually an HTTP (web) server, thatallow developers to create custom dynamic applications. The most popular and stable servlet containers havelong been available for Unix environments. With the introduction of the Unix-based Mac OS X, server-side Javais finally a serious option for web developers working on the Mac.

In this article, I’ll show you how to install and configure the Tomcat servlet container on your Mac OS Xplatform. Then I’ll describe how you can create and deploy some simple servlets and JavaServer Pages (JSPs).In Part II you’ll see how to use Javaserver Pages (JSP) with Tomcat. 

The Jakarta Tomcat Servlet Container

Tomcat is the Jakarta Project’s open-source servlet container and is released under the Apache SoftwareLicence. Tomcat provides support for Java Servlet and JSP technologies. It’s a feature-rich platform withcapabilities far beyond what we’ll discuss here. Once you’ve gone through this article and the following article, Iencourage you to visit the Jakarta Tomcat Site to learn more.

Installing Tomcat on Mac OS X

Since Mac OS X comes standard with Java 2, installing Tomcat is a breeze. First, you’ll want to download acurrent stable binary release of Tomcat from http://jakarta.apache.org/site/binindex.html. At the time of thiswriting (summer 2001), the latest stable version of Tomcat was 4.0.1, so I have downloaded the file jakarta-tomcat-4.0.1.tar.gz.

Once you’ve downloaded the file, you’ll want to extract it into an appropriate directory, like /usr/local/. To

install files into /usr/local/, you’ll need to give yourself administrator privileges via the sudo command. Also, if 

you don’t have gnutar, you’ll need to install it. It’s part of the Mac OS X Developer Tools. 

liz@localhost:~> sudo sh

Password:

root@localhost:~> mv jakarta-tomcat-4.0.1.tar.gz /usr/local/

root@localhost:~> cd /usr/local/

8/6/2019 Tomcat in MAC

http://slidepdf.com/reader/full/tomcat-in-mac 2/11

root@localhost:local> gnutar -xzvf jakarta-tomcat-4.0.1.tar.gz

That’s it. Tomcat is now installed under /usr/local/jakarta-tomcat-4.0.1/ — or a similar directory if you installed

a different version. Please note that you will need to change the filenames and paths in the examples in thistutorial if your version or installation directory are different from mine.

Now you’ll probably want to change ownership of all the Tomcat files and directories to someone other than theadministrator. Since I use the login “liz” on my system, I’m changing ownership of all files underjakarta-tomcat-

4.0.1/ to “liz”. 

root@localhost:local> chown -R liz:staff /usr/local/jakarta-tomcat-4.0.1

Starting and Stopping Tomcat

Tomcat expects certain environment variables to be defined before it starts. In order to simplify the startup andshutdown processes, you can create re-usable scripts. I usually store scripts like these in a directorycalled bin under my home directory. (That’s pretty standard in the Unix world.) 

liz@localhost:~> mkdir bin

liz@localhost:~> cd bin

liz@localhost:bin>

Now you can create a file (using your favorite text editor, must be saved with unix line endings)called~/bin/start_tomcat with the following contents:

#!/bin/sh

export CATALINA_HOME=/usr/local/jakarta-tomcat-4.0.1

export JAVA_HOME=/usr

$CATALINA_HOME/bin/startup.sh

And a file called ~/bin/stop_tomcat with these contents:

#!/bin/sh

export CATALINA_HOME=/usr/local/jakarta-tomcat-4.0.1

export JAVA_HOME=/usr

$CATALINA_HOME/bin/shutdown.sh

Finally, you must make these files executable:

8/6/2019 Tomcat in MAC

http://slidepdf.com/reader/full/tomcat-in-mac 3/11

liz@localhost:bin> chmod ug+x start_tomcat stop_tomcat

Tomcat as a Stand-alone Service

Tomcat comes with a built-in HTTP server. By default, it runs as a stand-alone service on port 8080. You’ll learn

how to use Tomcat with Apache below. If you’d rather use Tomcat by itself on port 80, you can change the portvalue in your server.xml file, as you’ll see shortly. For now, you can start Tomcat using the script you justcreated.

liz@localhost:~> ~/bin/start_tomcat

Now you can visit http://localhost:8080/ in your web browser to make sure things worked.

If you are unable to connect to Tomcat, you can check for errors by examining your error log:

liz@localhost:~> cat /usr/local/jakarta-tomcat-4.0.1/logs/catalina.out

Viewing the Example ServletsTomcat comes with several example servlets. If you used the above instructions to install Tomcat, you can viewthe examples by pointing your browser to http://localhost:8080/examples/servlets/ 

Custom Web Applications: Configuring Tomcat via server.xml

In order to deploy your own custom servlets, you will need to set a few parameters in the global configuration

file, called server.xml. If you’ve followed the steps above for installing Tomcat, you’ll find the file

at /usr/local/jakarta-tomcat-4.0.1/conf/server.xml . When you’re ready for an overview of all the directives

8/6/2019 Tomcat in MAC

http://slidepdf.com/reader/full/tomcat-in-mac 4/11

in server.xml (and there are many), see your local Tomcat documentation at http://localhost:8080/tomcat-

docs/config/index.html or go to http://jakarta.apache.org/tomcat/tomcat-4.0-doc/config/index.html. For now,however, you can follow the instructions in the section below to get up and running.

Creating and Deploying Servlets

Now you’re ready to deploy your own web applications. First, you’ll make some changes to your server.xmlfile in

order to register your first custom application. In Java servlet lingo, a “Context” represents a web application.The Java Servlet Specification (version 2.2 or later) is fairly particular about the directory structure, which I’llcover shortly. For more on Contexts, see your local Tomcat documentation athttp://localhost:8080/tomcat-docs/config/context.html or visit http://jakarta.apache.org/tomcat/tomcat-4.0-doc/config/context.html. 

In the example below, the application will be accessible via http://localhost:8080/mine (if you are runningTomcat as a stand-alone service on port 8080) or http://localhost/mine (if you are using Tomcat with Apacheon the default HTTP port, 80). The files will live in /usr/local/jakarta-tomcat-4.0.1/webapps/mine .

Notice that the reloadable parameter for the new context is set to “true” for now. This means that servlets are

automatically checked for changes, and are reloaded if necessary. If reloadable is “false”, you will need to re-

start Tomcat each time you re-compile any class files. Reloading is a handy feature, but it causes a significantload on the server, and should be turned off once your web application has been launched and is viewable bythe public.

<!-- you probably want to set "reloadable"

to "true" during development, but you should

set it to be "false" in production. -->

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

<Logger className="org.apache.catalina.logger.FileLogger"

prefix="localhost_mine_log." suffix=".txt"

timestamp="true"/>

</Context>

<!-- note that I've added this new context entry

right above the pre-existing "Examples" context -->

<!-- Tomcat Examples Context -->

Now that you’ve added a new context, you’ll want to create the appropriate directories. For a more completeguide to the standard directory layout defined in the 2.2 Servlet Specification, see your local docsat http://localhost:8080/tomcat-docs/appdev/deployment.html or seehttp://jakarta.apache.org/tomcat/tomcat-4.0-doc/appdev/deployment.html. For now, however, I’ll guide you through a minimal installation that conformsto the standard. Create the following directories:

8/6/2019 Tomcat in MAC

http://slidepdf.com/reader/full/tomcat-in-mac 5/11

liz@localhost:~> cd /usr/local/jakarta-tomcat-4.0.1/webapps

liz@localhost:webapps> mkdir mine

liz@localhost:webapps> mkdir mine/WEB-INF

liz@localhost:webapps> mkdir mine/WEB-INF/classes

liz@localhost:webapps> mkdir mine/WEB-INF/lib

Now you need to create a new configuration file for your application. You can do this by copying an exampleconfiguration file into your new directory and making a few changes.

liz@localhost:webapps> cp ./tomcat-docs/appdev/web.xml.txt ./mine/WEB-INF/web.xml

Next you’ll make a few changes to your new web.xml file. First, set the display-name, description,

and webmasterparameters to appropriate values for your application.

<display-name>My Web Application</display-name>

<description>

Examples by Me

</description>

[...]

<context-param>

<param-name>webmaster</param-name>

<param-value>your@email.address</param-value>

<description>

The EMAIL address of the administrator to whom questions

and comments about this application should be addressed.

</description>

</context-param>

Finally, add a Servlet Definition for your first servlet, along with a mapping so that the servlet can be viewed viaa short URL.

8/6/2019 Tomcat in MAC

http://slidepdf.com/reader/full/tomcat-in-mac 6/11

<servlet>

<servlet-name>Hi</servlet-name>

<description>

Testing

</description>

<servlet-class>Hi</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>Hi</servlet-name>

<url-pattern>/Hi</url-pattern>

</servlet-mapping>

“Hello World” servlet 

Now you’re ready to create your first servlet. Create a file called webapps/mine/WEB-INF/classes/Hi.java with the

following code:

import java.io.*;

import java.text.*;

import java.util.*;

import javax.servlet.*;

import javax.servlet.http.*;

/**

* My test servlet

*

* @author Liz Warner

*/

8/6/2019 Tomcat in MAC

http://slidepdf.com/reader/full/tomcat-in-mac 7/11

8/6/2019 Tomcat in MAC

http://slidepdf.com/reader/full/tomcat-in-mac 8/11

Frameworks/JavaVM.framework/Versions/1.3/Classes/classes.jar:/usr/local/

jakarta-tomcat-4.0.1/common/lib/servlet.jar"

This command will work if you’re using the tcsh shell (if you’re not sure which you’re using, it’s probably tcsh):

liz@localhost:classes> setenv CLASSPATH "/System/Library/

Frameworks/JavaVM.framework/Versions/1.3/Classes/classes.jar:/usr/local/

jakarta-tomcat-4.0.1/common/lib/servlet.jar"

Now you should be ready to compile the servlet. You will also need to restart Tomcat so that your new webapplication will be recognized. If you are new to Unix-based environments, please note that javac is like many

Unix commands in that it exits silently on success. In other words, if you don’t see any error messages,your .java file has been compiled successfully. I’ve added some ls commands to the listing below which you can

use if you’d like to see that your .class file was created.

liz@localhost:classes> ls

Hi.java

liz@localhost:classes> javac Hi.java

liz@localhost:classes> ls

Hi.class Hi.java

liz@localhost:classes> ~/bin/stop_tomcat

liz@localhost:classes> ~/bin/start_tomcat

Now that Tomcat has restarted, you should be ready to load the servlet in your browser.

8/6/2019 Tomcat in MAC

http://slidepdf.com/reader/full/tomcat-in-mac 9/11

 

Servlet to Process a Simple email Form

Now that you’ve learned how to create and deploy servlets, let’s work on something a little more interesting.This servlet, called “mail”, will send an email message to a recipient specified in the code. To register the

servlet, you’ll want to modify the web.xml file for your web application one more time. These lines should look

familiar:

<servlet>

<servlet-name>mail</servlet-name>

<description>

mail example

</description>

<servlet-class>mail</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>mail</servlet-name>

<url-pattern>/mail</url-pattern>

8/6/2019 Tomcat in MAC

http://slidepdf.com/reader/full/tomcat-in-mac 10/11

</servlet-mapping>

Now you can create a file called classes/mail.java that looks like this. 

Once you’ve created the file, you can compile it using the javac command. If it won’t compile, don’t worry. You

may need to add another library to your CLASSPATH variable with one of the following commands (depending

on your current login shell). For sh or bash, here’s the command: 

liz@mail:classes> export

CLASSPATH="$CLASSPATH:/usr/local/jakarta-tomcat-4.0.1/common/lib/mail.jar"

For tcsh, it’s this: 

liz@mail:classes> setenv

CLASSPATH $CLASSPATH":/usr/local/jakarta-tomcat-4.0.1/common/lib/mail.jar"

Now when you visit http://localhost:8080/mine/mail, you should see your new servlet in action:

8/6/2019 Tomcat in MAC

http://slidepdf.com/reader/full/tomcat-in-mac 11/11

 

Conclusion

In this tutorial you’ve learned how to install and run the Jakarta Tomcat servlet container on your Mac OS Xsystem, run some example servlets, and deploy your own web applications. In Part II you’ll see how you canuse JavaServer Pages (JSP), and the Jakarta Project’s JSP Tag Libraries (Taglibs). Part II will also include anoverview of Java database programming on Mac OS X using JDBC and MySQL.

More Information

  Java and Tomcat on Mac OS X, Part II 

Get information on Apple products.

Visit the Apple Store online or at retail locations.

1-800-MY-APPLE

Copyright © 2011 Apple Inc.

All rights reserved. | Terms of use | Privacy Notice