Professional Apache Tomcat 6

642 Pages·2007·6.13 MB·English

by  Vivek Chopra

Professional
Apache Tomcat 6
Vivek Chopra
Sing Li
Jeff Genender
Wiley Publishing, Inc.
ffffiirrss..iinndddd iiiiii 77//1111//0077 66::5544::4433 PPMM
Professional Apache Tomcat 6
Published by
Wiley Publishing, Inc.
10475 Crosspoint Boulevard
Indianapolis, IN 46256
www.wiley.com
Copyright © 2007 by Wiley Publishing, Inc., Indianapolis, Indiana
Published simultaneously in Canada
ISBN: 978-0-471-75361-2
Manufactured in the United States of America
10 9 8 7 6 5 4 3 2 1
Library of Congress Cataloging-in-Publication Data
Chopra, Vivek.
Professional Apache Tomcat 6 / Vivek Chopra, Sing Li, and Jeff Genender.
p. cm.
Includes index.
ISBN 978-0-471-75361-2 (paper/website)
1. Apache Tomcat. 2. Web servers. 3. Web site development. 4. Internet programming. I. Li, Sing. II.
Genender, Jeff M. III. Title.
TK5105.8885.A63C47 2007
005.7'1376—dc22
2007020134
No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any
means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under
Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the
Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center,
222 Rosewood Drive, Danvers, MA 01923, [phone], fax [phone]. Requests to the Publisher for per-
mission should be addressed to the Legal Department, Wiley Publishing, Inc., 10475 Crosspoint Blvd., Indian-
apolis, IN 46256, [phone], fax [phone], or online at http://www.wiley.com/go/permissions.
Limit of Liability/Disclaimer of Warranty: The publisher and the author make no representations or warranties
with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties,
including without limitation warranties of fitness for a particular purpose. No warranty may be created or
extended by sales or promotional materials. The advice and strategies contained herein may not be suitable for
every situation. This work is sold with the understanding that the publisher is not engaged in rendering legal,
accounting, or other professional services. If professional assistance is required, the services of a competent profes-
sional person should be sought. Neither the publisher nor the author shall be liable for damages arising herefrom.
The fact that an organization or Website is referred to in this work as a citation and/or a potential source of further
information does not mean that the author or the publisher endorses the information the organization or Website
may provide or recommendations it may make. Further, readers should be aware that Internet Websites listed in
this work may have changed or disappeared between when this work was written and when it is read.
For general information on our other products and services please contact our Customer Care Department
within the United States at [phone], outside the United States at [phone] or fax [phone].
Trademarks: Wiley, the Wiley logo, Wrox, the Wrox logo, Wrox Programmer to Programmer, and related trade dress
are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affiliates, in the United States and
other countries, and may not be used without written permission. All other trademarks are the property of their
respective owners. Wiley Publishing, Inc., is not associated with any product or vendor mentioned in this book.
Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be
available in electronic books.
ffffiirrss..iinndddd iivv 77//1111//0077 66::5544::4444 PPMM
To Rebecca and Rohan, thanks for all your patience and support.
—Vivek
To my guiding light and spiritual support for the last two decades, Kim.
—Sing
To my wonderful wife, Nazarena, and my children, Madisyn, Weston, and Coleton.
I could not have done this without you.
—Jeff
ffffiirrss..iinndddd vv 77//1111//0077 66::5544::4455 PPMM
About the Authors
Vivek Chopra has more than 13 years of experience as a software architect, developer, and team lead and
has worked in a number of Silicon Valley companies and startups. He writes actively on technology and is
the author of more than half a dozen books on Java, open source software, XML, and Web services. Vivek
has pending patents on Web service technologies, and has been a Java Community Process (JCP) member
for the past three years. He also serves on the expert group for JSR 280 (XML API for Java ME).
Sing Li (who was bitten by the microcomputer bug in the late 1970s) has grown up with the Micropro-
cessor Age. His first personal computer was a $99 do-it-yourself Netronics COSMIC ELF with 256 bytes
of memory, mail-ordered from the back pages of Popular Electronics magazine. A 20-year industry vet-
eran, Sing is a system developer, open source software contributor, and freelance writer specializing in
Java technology, and embedded and distributed systems architecture. He regularly writes for several
popular technical journals and e-zines, and is the creator of the “Internet Global Phone,” one of the very
first Internet phones available. He has authored and co-authored a number of books across diverse tech-
nical disciplines including Geronimo, Tomcat, JSP, servlets, XML, Jini, media streaming, device drivers,
and JXTA.
Jeff Genender has over 18 years of software architecture, team lead, and development experience in
multiple industries. Jeff is an active committer and Project Management Committee (PMC) member for
Apache Geronimo, and a committer on OpenTerracotta, OpenEJB, ServiceMix, and Mojo (Maven plug-
ins). Jeff also serves as a member of the Java Community Process (JCP) expert group for JSR-313 (Java
Platform, Enterprise Edition 6 [Java EE 6] Specification) as a representative of the Apache Software
Foundation. Jeff is an open source evangelist and has successfully brought open source development
efforts, initiatives, and success stories into a number of Global 2000 companies, saving these organiza-
tions millions in licensing costs.
ffffiirrss..iinndddd vviiii 77//1111//0077 66::5544::4455 PPMM
Credits
Executive Editor Vice President and Executive Group Publisher
Bob Elliott Richard Swadley
Development Editor Vice President and Executive Publisher
Sydney Jones Joseph B. Wikert
Technical Editors Project Coordinator, Cover
Rupert Jones Adrienne Martinez
Anne Horton
Proofreader
Copy Editor Kathryn Duggan
Nancy Rapoport
Indexer
Editorial Manager Johnna VanHoose Dinse
Mary Beth Wakefield
Anniversary Logo Design
Production Manager Richard Pacifico
Tim Tate
ffffiirrss..iinndddd iixx 77//1111//0077 66::5544::4455 PPMM
Contents
Introduction xxiii
Chapter 1: Apache Tomcat 1
Humble Beginnings: The Apache Project 2
The Apache Software Foundation 3
Tomcat 3
Distributing Tomcat: The Apache License 4
Comparison with Other Licenses 5
The Big Picture: Java EE 6
Java APIs 6
The Java EE APIs 7
Java EE Application Servers 8
“Agree on Standards, Compete on Implementation” 8
Tomcat and Application Servers 9
Tomcat and Web Servers 9
Summary 10
Chapter 2: Web Applications: Servlets, JSPs, and More 13
A Brief History of Web Applications 13
CGI Scripts: The First Mechanism for Dynamic Content 13
Server Side Java: Servlets 14
JavaServer Pages 19
JSP Tag Libraries 22
JSP EL 23
MVC Architecture 24
Using Appropriate Web Technologies 25
Building and Distributing Web Applications 26
Summary 27
Chapter 3: Tomcat Installation 29
Installing the Java Virtual Machine 29
Installing the JVM on Windows 30
Installing the JVM on Linux 32
ffttoocc..iinndddd xxii 77//1111//0077 11::4488::4477 PPMM
Contents
Installing Tomcat 34
Deciding Which Distribution to Install 34
Verifying the Downloaded File 35
Tomcat Windows Installer 36
Installing Tomcat on Windows Using the ZIP File 41
Installing Tomcat on Linux 42
Building Tomcat from Source 44
Do You Need to Build Tomcat from the Source Code? 44
Downloading the Source Release 44
Subversion Repository 45
Building a Source Release 45
The Tomcat Installation Directory 46
Installing APR 47
Troubleshooting and Tips 48
Class Version Error 49
The Port Number Is in Use 49
Running Multiple Instances 49
A Proxy Is Blocking Access 49
Summary 50
Chapter 4: Tomcat Architecture 51
Tomcat Directory Overview 51
bin Directory 52
conf Directory 52
lib Directory 53
logs Directory 53
temp Directory 53
webapps Directory 53
work Directory 54
An Overview of Tomcat Architecture 54
The Server 55
The Service 56
The Remaining Classes in the Tomcat Architecture 59
Connector Architecture 59
Communication Paths 60
Connector Protocols 61
Choosing a Connector 63
Lifecycle 64
Lifecycle Interface 65
LifecycleListener Interface 65
Configuration by Architecture 66
Summary 67
xii
ffttoocc..iinndddd xxiiii 77//1111//0077 11::4488::4488 PPMM
Contents
Chapter 5: Basic Tomcat Configuration 69
Tomcat 6 Configuration Essentials 70
Files in $CATALINA_HOME/conf 71
Basic Server Configuration 71
Server Configuration via the Default server.xml 72
Operating Tomcat in Application Server Configuration 75
Web Application Context Definitions 82
The Default context.xml File 82
Authentication and the tomcat-users.xml File 86
The Default Deployment Descriptor — web.xml 86
How server.xml, Context Descriptors, and web.xml Work Together 91
Fine-Grained Access Control: catalina.policy 94
catalina.properties: Finer-Grained Control over Access Checks 97
Bootstrapping Configuration 97
A Final Word on Differentiating Between Configuration and Management 98
Tomcat 6 Web-Based GUI Configurator 98
Summary 100
Chapter 6: Advanced Tomcat Features 103
Valves — Interception Tomcat-Style 104
Standard Valves 104
Access Log Implementation 105
Scope of Log Files 106
Single Sign-On Implementation 108
Multiple Sign-On Without the Single Sign-On Valve 109
Configuring a Single Sign-On Valve 111
Form Authenticator Valve 112
Restricting Access via a Request Filter 112
Remote Address Filter 112
Remote Host Filter 113
Configuring Request Filter Valves 113
Request Dumper Valve 114
Persistent Sessions 115
The Need for Persistent Sessions 115
Configuring a Persistent Session Manager 115
JNDI Resource Configuration 118
What Is JNDI? 118
Tomcat and JNDI 119
Typical Tomcat JNDI Resources 120
Configuring Resources via JNDI 121
xiii
ffttoocc..iinndddd xxiiiiii 77//1111//0077 11::4488::4488 PPMM
Contents
Configuring a JDBC DataSource 124
Configuring Mail Sessions 126
Configuring Lifecycle Listeners 129
Lifecycle Events Sent by Tomcat Components 129
The <Listener> Element 129
Tomcat 6 Lifecycle Listeners Configuration 130
Summary 133
Chapter 7: Web Application Configuration 135
Understanding the Contents of a Web Application 135
Public Resources 136
The WEB-INF Directory 138
The META-INF Directory 139
Understanding the Deployment Descriptor (web.xml) 140
The Servlet 2.3–Style Deployment Descriptor 141
The Servlet 2.4/2.5–Style Deployment Descriptor 154
Summary 171
Chapter 8: Web Application Administration 173
Sample Web Application 173
Tomcat Manager Application 175
Enabling Access to the Manager Application 176
Manager Application Configuration 178
Tomcat Manager: Web Interface 180
Displaying Tomcat Server Status 180
Managing Web Applications 181
Deploying a Web Application 182
Tomcat Manager: Managing Applications with Ant 182
Known Issue: Failure While Undeploying Web Applications on Windows 188
Tomcat Manager — Using HTTP Requests 189
List Deployed Applications 190
Deploying a New Application 190
Installing/Deploying Applications in Tomcat 6 191
Deploying a New Application Remotely 192
Deploying a New Application from a Local Path 192
Reloading an Existing Application 194
Listing Available JNDI Resources 195
Listing OS and JVM Properties 196
Stopping an Existing Application 196
Starting a Stopped Application 197
Undeploying a Web Application 198
xiv
ffttoocc..iinndddd xxiivv 77//1111//0077 11::4488::4499 PPMM
Contents
Displaying Session Statistics 198
Querying Tomcat Internals Using the JMX Proxy Servlet 199
Setting Tomcat Internals Using the JMX Proxy Servlet 200
Possible Errors 200
Security Considerations 201
Tomcat Deployer 203
Summary 203
Chapter 9: Class Loaders 205
Class Loader Overview 205
Standard Java SE Class Loaders 207
More on Class Loader Behavior 210
Creating a Custom Class Loader 211
Why Is a Custom Class Loader Needed for Tomcat? 211
Security and Class Loaders 212
Class Loader Delegation 212
Core Class Restriction 212
Separate Class Loader Namespaces 213
SecurityManager 213
Tomcat and Class Loaders 214
System Class Loader 215
Endorsed Standards Override Mechanism 215
Common Class Loader 215
Web Application Class Loader 216
Dynamic Class Reloading 217
Common Class Loader Pitfalls 218
Packages Split Among Different Class Loaders 218
Singletons 218
XML Parsers 219
Summary 220
Chapter 10: HTTP Connectors 221
HTTP Connectors 222
Tomcat 6 HTTP/1.1 Connector 223
The Advanced NIO Connector 227
Comet Asynchronous IO Support 228
The Native APR Connector 228
Configuring Tomcat for CGI Support 232
Configuring Tomcat for SSI Support 234
Configuring the Tomcat 6 SSI Servlet 235
Configuring the Tomcat 6 SSI Filter 237
xv
ffttoocc..iinndddd xxvv 77//1111//0077 11::4488::4499 PPMM