XML, XSLT, Java, and JSP: A Case Study in Developing a Web Application docx

XML, XSLT,

Java, and JSP

:

A Case Study in

Developing a

Web Application

Contents At a Glance

1 Introduction and Requirements

2 An Environment for Java Software

Development

3 Java Servlets and JavaServer Pages:

Jakarta Tomcat

4 XML and XSLT: Xerces and Xalan

5 bonForum Chat Application: Use

and Design

6 bonForum Chat Application:

Implementation

7 JavaServer Pages:The Browseable

User Interface

8 Java Servlet and Java Bean:

BonForumEngine and

BonForumStore

9 Java Applet Plugged In:

BonForumRobot

10 JSP Taglib:The bonForum

Custom Tags

11 XML Data Storage Class:

ForestHashtable

12 Online Information Sources

A CDROM Contents

B Some Copyrights and Licenses

C Source Code for bonForum Web

Application

D Sun Microsystems, Inc. Binary

Code License Agreement

00 1089-9 FM 6/26/01 8:20 AM Page i

00 1089-9 FM 6/26/01 8:20 AM Page ii

XML, XSLT, Java

,

and JSP

:

A Case Study in

Developing a Web

Application

201 West 103rd Street, Indianapolis, Indiana 46290

An Imprint of Pearson Education

Boston • Indianapolis • London • Munich • New York • San Francisco

Westy Rockwell

www.newriders.com

00 1089-9 FM 6/26/01 8:20 AM Page iii

Publisher

David Dwyer

Associate Publisher

Al Valvano

Executive Editor

Stephanie Wall

Managing Editor

Gina Brown

Product Marketing

Manager

Stephanie Layton

Publicity Manager

Susan Nixon

Software

Development

Specialist

Jay Payne

Project Editor

Elise Walter

Copy Editor

Krista Hansing

Indexer

Larry Sweazy

Manufacturing

Coordinator

Jim Conway

Book Designer

Louisa Klucznik

Cover Designer

Aren Howell

Proofreader

Jeannie Smith

Composition

Gina Rexrode

XML, XSLT, Java, and JSP: A Case

Study in Developing a Web Application

Translation from the German language edition of: XML,

XSLT, Java, and JSP by Westy Rockwell  2000 Galileo Press

GmbH Bonn, Germany

FIRST EDITION: July 2001

All rights reserved. No part of this book may be reproduced

or transmitted in any form or by any means, electronic or

mechanical, including photocopying or recording, or by any

information storage and retrieval system, without written

permission from the publisher, except for the inclusion of

brief quotations in a review.

International Standard Book Number: 0-7357-1089-9

Library of Congress Catalog Card Number: 00-110885

05 04 03 02 01 7 6 5 4 3 2 1

Interpretation of the printing code:The rightmost double￾digit number is the year of the book’s printing; the right￾most single-digit number is the number of the book’s

printing. For example, the printing code 01-1 shows that the

first printing of the book occurred in 2001.

Composed in Bembo and MCPdigital by New Riders

Publishing

Printed in the United States of America

Trademarks

All terms mentioned in this book that are known to be

trademarks or service marks have been appropriately capital￾ized. New Riders Publishing cannot attest to the accuracy of

this information. Use of a term in this book should not be

regarded as affecting the validity of any trademark or service

mark. Java and JavaServer Pages (JSP) are registered trade￾marks of Sun Microsystems, Inc.

Warning and Disclaimer

This book is designed to provide information about XML,

XSLT, Java, and JSP. Every effort has been made to make this

book as complete and as accurate as possible, but no war￾ranty or fitness is implied.

The information is provided on an as-is basis.The authors

and New Riders Publishing shall have neither liability nor

responsibility to any person or entity with respect to any loss

or damages arising from the information contained in this

book or from the use of the discs or programs that may

accompany it.

00 1089-9 FM 6/26/01 8:20 AM Page iv

❖

THIS BOOK IS DEDICATED

TO MEMORIES

OF YOU,

DON ROCKWELL, SR.

YOU GAVE SO MUCH TO ME!

DID I EVER SAY ENOUGH, SOMEHOW,

FOR YOU TO KNOW HOW MUCH I LOVE YOU?

WITHOUT YOUR LOVE AND KIND

GENEROSITY,

I WOULD NOT FEEL HALF SO FORTUNATE

TO BE ALIVE TODAY. BESIDES THAT,

YOU TAUGHT ME TO ENJOY THIS LIFE,

SWIM IN THE BLUE OCEANS,AND

DIVE DOWN SO DEEPLY.

I WOULD MISS YOU FOREVER,

IF I WERE NOT SO SURE

THAT YOU ARE

HERE.

THANK YOU!

W. R.

❖

00 1089-9 FM 6/26/01 8:20 AM Page v

TABLE OF CONTENTS

1 Introduction and

Requirements 1

1.1 The Goal of This Book 1

1.2 Why Use This Book? 2

1.3 How to Use This Book 4

1.4 Some Choices Facing Web

Application Developers 6

1.5 Development Choices Made for

This Book 8

1.6 A Note About Platform

Independence 14

2 An Environment for

Java Software

Development 15

2.1 Java 2 Platform,

Standard Edition 15

2.2 Compiling Java Programs 19

2.3 Running Java Programs 30

2.4 Debugging Java Programs 32

2.5 Other Features of ElixirIDE 33

3 Java Servlets and

JavaServer Pages:

Jakarta Tomcat 35

3.1 Apache Software

Foundation 35

3.2 Jakarta Tomcat 36

3.3 Installing Tomcat 37

3.4 Running Tomcat 39

00 1089-9 FM 6/26/01 8:21 AM Page vi

3.5 Tomcat Examples of Servlets and

JSPs 49

3.6 Adding Your Tomcat Web

Application 49

3.7 Java Servlets and JSPs 53

3.8 The ServletConfig and

ServletContext Classes 57

3.9 Web Application Scopes 58

4 XML and XSLT: Xerces

and Xalan 61

4.1 Apache XML Project 61

4.2 Installing Xerces 62

4.3 Xerces Parses XML 64

4.4 SAX Sees XML as Events 67

4.5 Installing Xalan 67

4.6 Xalan Transforms XML Using

XSLT 70

4.7 Using Beanshell with Xalan 72

4.8 Using Xalan from the Command

Line 73

4.9 Zvon XSL Tutorial 73

4.10 Xerces and Xalan versus XT

and XP 73

4.11 JSP and XML Synergy 74

5 bonForum Chat Application:

Use and Design 77

5.1 Installing and Running

bonForum 77

5.2 Changing the bonForum Web

Application 83

5.3 Using XML to Design Web

Applications 86

5.4 XML Data Flows in Web

Applications 98

Contents vii

00 1089-9 FM 6/26/01 8:21 AM Page vii

6 bonForum Chat Application:

Implementation 103

6.1 Building the bonForum Web

Chat 103

6.2 Displaying and Selecting Chat

Subjects 138

6.3 Displaying Chat Messages 140

6.4 Finding the Chat Element 146

6.5 Displaying and Selecting Chats

148

6.6 Displaying Guests in Chat 150

6.7 Outputting the bonForum Data

as XML 150

6.8 Future of bonForum Project

151

7 JavaServer Pages:The

Browseable User

Interface 155

7.1 JSP-Based Web Applications

155

7.2 Viewing bonForum from Its JSP

Documents 163

7.3 Further Discussion About the JSP

in bonForum 187

8 Java Servlet and Java Bean:

BonForumEngine and

BonForumStore 189

8.1 The BonForumEngine

Servlet 189

8.2 The BonForumStore Class 262

9 Java Applet Plugged In:

BonForumRobot 285

9.1 Hands-on with Java Applets 285

9.2 XSLTProcessor Applet 290

9.3 BonForumRobot 290

viii Contents

00 1089-9 FM 6/26/01 8:21 AM Page viii

10 JSP Taglib:The bonForum

Custom Tags 303

10.1 Java Servlets, JSP, and Tag

Libraries 303

10.2 The bonForum Tag Library

316

10.3 The OutputDebugInfoTag

Class 324

10.4 The OutputPathNamesTag

Class 331

10.5 The OutputChatMessagesTag

Class 340

10.6 XSLT and the TransformTag

Class 352

10.7 Displaying the Available Chats

371

10.8 Displaying the Available

bonForums 376

10.9 Displaying the Guests

in a Chat 379

11 XML Data Storage Class:

ForestHashtable 385

11.1 Overview of bonForum Data

Storage 385

11.2 The NodeKey Class 387

11.3 The BonNode Class 388

11.4 ForestHashtable Maps Data

Trees 390

11.5 Caching Keys for Fast Node

Access 398

11.6 Adding ForestHashtable Nodes

404

11.7 Deleting ForestHashtable Nodes

411

11.8 Editing ForestHashtable Nodes

414

11.9 Getting ForestHashtable as

XML 416

Contents ix

00 1089-9 FM 6/26/01 8:21 AM Page ix

11.10 More Public ForestHashtable

Methods 424

11.11 Initializing the bonForumXML

Database 427

11.12 Runtime bonForumXML

Database 429

11.13 More ForestHashtable

Considerations 432

12 Online Information

Sources 437

12.1 Always Useful Sites 437

12.2 Apache Software Foundation

438

12.3 Big Corporations 438

12.4 CSS 439

12.5 DOM Information 439

12.6 HTML 439

12.7 HTTP 439

12.8 Java 440

12.9 JavaServer Pages 441

12.10 Java Servlets 443

12.11 Linux 445

12.12 Open Source 445

12.13 RDF 446

12.14 Web Applications 446

12.15 Web Browsers 446

12.16 Web Servers 446

12.17 XML 447

12.18 XSL 452

A CD-ROM Contents 455

\Sun 456

\Apache 456

\bonForum 456

\tools 458

E-Book 458

x Contents

00 1089-9 FM 6/26/01 8:21 AM Page x

B Some Copyrights

and Licenses 459

BonForum License 459

Apache Xerces License 460

Apache Xalan License 461

Jakarta Tomcat License 462

C Source Code for

bonForum Web

Application 465

D Sun Microsystems, Inc.

Binary Code License

Agreement 703

Index

Contents xi

00 1089-9 FM 6/26/01 8:21 AM Page xi

xii

About the Author

Westy Rockwell considers himself a world citizen. Currently he is a

senior developer at tarent GmbH, a Web development company in

Bonn, Germany. His greatest pleasure is enjoying the company of his

wife, Zamina, and their two daughters, Joaquina and Jennifer.

Somehow, they tolerate his intense involvement with computers.

Westy has more than 15 years of experience as a professional soft￾ware developer, but his involvement with computers dates back

longer yet. In 1965, he programmed the Pythagorean theorem into

an IBM 1620 with punched cards. His faculty adviser told him to

stop spending so much time on programming, which had no career

future. In 1970, while studying IBM 360 programming, he was con￾sidered too radical for saying that computers would one day play

chess. It was not until the early 1980s, with the arrival of micro￾computers, that his career and his passion could merge.

His real software education came from deeply hacking many

microcomputers, including the ZX80, the Osborne, the Vic20, the

C64, various Amigas, and, of course, IBM PCs. His career, mean￾while, involved him with more respectable software and hardware,

including UNIX, workstations, minicomputers, mainframes, and, of

course, IBM PCs. Interest in hardware design, along with C and

assembly languages, culminated in 1994 when he built the prototype

for an extremely successful dual-processor alcohol analyser, including

the PCB design, operating system, and application software.

Soon afterward, while developing man-machine interfaces, the pre￾release version of Borland Delphi turned Westy into a Windows

developer. He went on to work on three-tier systems based on

Windows NT, including corporate asset management, document

imaging, and work management systems. For more than a year now

he has refused to touch SQL or Visual tools, and he is enthusiastically

pursuing Web browser- and server-based applications using Java,

Tomcat, Xerces, and Xalan.

00 1089-9 FM 6/26/01 8:21 AM Page xii

xiii

About the Technical Reviewers

These reviewers contributed their considerable hands-on expertise to the entire

development process for XML, XSLT, Java, and JSP:A Case Study in Developing a Web

Application.As the book was being written, these dedicated professionals reviewed all

the material for technical content, organization, and flow.Their feedback was critical

to ensuring that XML, XSLT, Java, and JSP:A Case Study in Developing a Web

Application fits our reader’s need for the highest-quality technical information.

Brad Irby holds a bachelor of computer science degree from the University of

North Carolina, and he has been a programmer and system designer since 1985. He

has worked with many different languages and databases over the years, but he now

specializes in application development using a Microsoft SQL Server back end.A pri￾vate consultant for eight years, Brad has been following the progress of the W3C and

the XML specification since its inception, and he has done extensive work using the

XML extensions of SQL Server to transfer data over secure internet links. He can be

reached at [email protected].

Perry Tew graduated from Georgia Institute of Technology with a degree in chemi￾cal engineering, but he has since fallen in love with computer programming. Perry

began his IT career as a MCSD and currently programs with Java. He works as an

integration specialist for a major contact lens producer. He spends his free time with

his wife, Paula, basking in they joy of parenthood brought by the arrival of their

newborn, Joshua.

Acknowledgments

Most of all, I want to thank Jennifer, Joaquina and Zamina Rockwell, who are the real

treasures in my life.Without their love, understanding, playfulness and patience this

book could never have been written.

There are so many others to thank, I know I will omit some here: those who

toiled behind the scenes, those who taught me, worked with me, helped me come to

this point in my professional career. If you are one of these, I would like to thank you

as well. Please forgive the unintentional omission of your name.

Thanks are especially due to Elmar Geese, CEO of tarent GmbH, for making this

book possible.Also, Manfred Weltecke, for his masterful translation of the first book

version into German, to which it largely owes its success. Much credit for that success

also belongs to Harald Aberfeld, Michael Klink and Florian Hawlitzek, for their tech￾nical editing of the German edition.

00 1089-9 FM 6/26/01 8:21 AM Page xiii

xiv

Thanks to all my colleagues at tarent GmbH, for their selfless support of the book

project:Alex Steeg,Alexander Scharch, Boris Esser, Harald Aberfeld, Hendrik Helwich,

Kerstin Weber, Markus Heiliger, Martina Hundhausen, Matthias Esken, May-Britt

Baumann, Michael Klink, Robert Schuster,Thomas Mueller-Ackermann,Vanessa

Haering, and Vera Schwingenheuer. My absence from their projects while working on

this book created extra work for them; I appreciate that truly.

Thanks to the staff of Galileo Press, especially my editors Judith Stevens and

Corinna Stefani, for making the German edition happen. Others there whose work

on the book is appreciated are: proofreaders Claudia Falk and Hoger Schmidt, cover

designer Barbara Thoben, illustrator Leo Leowald, producer Petra Strauch, and com￾puter typographer Joerg Gitzelmann.Thanks also to Petra Walther and Stefan

Krumbiegel of Galileo Press for supporting the German edition online.

Thanks to Lau Shih-Hor and Agnes Chin of Elixir Technologies, for adding value

to the CDROM.Thanks to the developers of TextPad, so useful for a technical writer.

Thanks to Jen Wilson for creating bonForum.links2go.com, in support of the book

project.

This book depends so much upon those who make the open source projects it and

its example project depend upon.Thanks to all involved with the Apache Software

Foundation, especially its Jakarta and Apache XML projects.Thanks also to the staff

and providers of SourceForge for making it a superb place to develop and learn about

open source software.Thanks to Sun for making its JDK available for learning Java.

Many thanks to the staff of New Riders who made the English version of the

book happen. Especially to Stephanie Wall (Executive Editor), who went way beyond

the call of duty to keep the book alive until publication, and to Elise Walter (Project

Editor), who always kept her good humor no matter how late my requests for changes

came to her.The book was vastly improved by the “no-holds-barred” technical edi￾tors, including Brad Irby, Erin Mulder, and Perry Tew.Thanks to Jay Payne (Media

Developer), who produced the CD-ROM.After working with words for over a year

myself, I know I owe so much of this book’s existence to Krista Hansing (Copy

Editor), Larry Sweazy (Indexer), Gina Rexrode (Compositor).Thanks also to Susan

Nixon (Public Relations).

Thanks to Jeffrey E. Northridge, whose friendship and partnership-in-programming

has been so valued by me.Thanks to Jaime del Palacio, a superb software developer

(and nephew).Thanks to PhoenixFire, for giving me that first, all-important chance as

a professional software developer (If you read this, please contact me!).Thanks to John

Haefeli of ISI, who provided so many difficult real-world problems to solve with C.

Thanks to Alvaro Pastor, Glenn Forrester, and all the gang who were at Intoximeters

West, especially to Doug, Iza, Petcy who helped so much to develop me as a software

developer.Thanks to Paul McEvoy for his mentoring and my appreciation of cafe

latte.Thanks to Elliot Mehrbach for helping me learn SQL and Delphi.

Finally, I would like to thank especially Daph, Cita and Marcos Rockwell, and all

my other relatives, for their unconditional love.Thanks also to Nature and Life, for

their unconditional and priceless support.

00 1089-9 FM 6/26/01 8:21 AM Page xiv

xv

Tell Us What You Think

As the reader of this book, you are the most important critic and commentator.We

value your opinion and want to know what we’re doing right, what we could do bet￾ter, what areas you’d like to see us publish in, and any other words of wisdom you’re

willing to pass our way.

As an Executive Editor at New Riders Publishing, I welcome your comments.You

can fax, email, or write me directly to let me know what you did or didn’t like about

this book—as well as what we can do to make our books stronger.

Please note that I cannot help you with technical problems related to the topic of this book,

and that due to the high volume of mail I receive, I might not be able to reply to every message.

When you write, please be sure to include this book’s title and author, as well as

your name and phone or fax number. I will carefully review your comments and share

them with the author and editors who worked on the book.

Fax: 317-581-4663

Email: [email protected]

Mail: Stephanie Wall

Executive Editor

New Riders Publishing

201 West 103rd Street

Indianapolis, IN 46290 USA

00 1089-9 FM 6/26/01 8:21 AM Page xv