Logging in Java with the JDK 1.4 Logging API and Apache log4j

333 Pages·2003·6.2 MB·English

by  Samudra Gupta (auth.)

Logging in Java with
the JDK 1.4 Logging API
and Apache log4j
SAMUDRA GUPTA
APress Media, LLC
Logging in Java with the JDK 1.4 Logging API and Apache log4j
Copyright ©2003 by Samudra Gupta
Originally published by Springer-Verlag New York, Inc. in 2003
Softcover reprint of the hardcover 1st edition 2003
All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying, recording, or by any information storage or retrieval
system, without the prior written permission of the copyright owner and the publisher.
Printed and bound in the United States of America 12345678910
Trademarked names may appear in this book. Rather than use a trademark symbol with every
occurrence of a trademarked name, we use the names only in an editorial fashion and to the benefit
of the trademark owner, with no intention of infringement of the trademark.
library of Congress Cataloging-in-Publication Data
Gupta, Samudra,l974-
Logging in Java with the JDK l.4logging API and Apache log4j I Samudra Gupta.
p.cm.
ISBN 978-1-4302-5398-3 ISBN 978-1-4302-0765-8 (eBook)
DOI 10.1007/978-1-4302-0765-8
l. Java (Computer program language) 2. Apache (Computer file : Apache
Group) 3. Application logging (Computer science) 4. Application software--Development-
Management. 5. Debugging in computer science. I. Title.
QA76.73.J38G86 2003
005.13'3--dc21
2003005480
Technical Reviewer: Jeff Heaton
Editorial Directors: Dan Appleman, Gary Cornell, Simon Hayes, Martin Streicher,
Karen Watterson, John Zukowski
Assistant Publisher: Grace Wong
Developmental Editors: Tracy Brown Collins, Ami Knox
Copy Editor: Ami Knox
Production Manager: Karl Brooks
Compositor: Susan Glinert Stevens
Proofreader: Lori Bring
Indexer: Ann Rogers
Artist and Cover Designer: Kurt Krames
Manufacturing Manager: Tom Debolski
The information in this book is distributed on an "as is" basis, without warranty. Although every
precaution has been taken in the preparation of this work, neither the author(s) nor Apress shall have
any liability to any person or entity with respect to any loss or damage caused or alleged to be caused
directly or indirectly by the information contained in this work.
To the lotus feet ofB hagavan Sri Ramakrishna
Contents at a Glance
About the Author and Technical Reviewer ............................................. viii
Acknowledgments ................................................................................................... ix
Preface ...................................................................................................................... x
Chapter 1 Introduction to Application Logging ................................ 1
Chapter 2 JDK 1.4 Logging API ................................................................. 11
Chapter 3 Formatting JDK 1.4 Logging Information ........................ 59
Chapter 4 Extending the Logging Framework ....................................... 73
Chapter 5 Understanding Apache log4j ................................................ 121
Chapter 6 Formatting Logging Information in log4j .................... 177
Chapter 7 Advanced Logging with log4j .............................................. 199
Chapter 8 Extending log4j to Create Custom
Logging Components .................................................................... 235
Chapter 9 Using the Apache Log Tag Library ................................... 285
Chapter 10 Best Practices ........................................................................ 299
Index ...................................................................................................................... 315
iv
Contents
About the Author and Technical Reviewer ............................. viii
Acknowledgments ............................................................................................. ix
Preface ...................................................................................................................... x
Chapter 1 Introduction to Application Logging ............. 1
What Is Logging? .................................................................................................. 1
Benefits of Logging ........................................................................................... 3
Disadvantages of Logging ................................................................................ 4
How Logging Works ................................................................................................ 5
Evaluating a Logging Package ........................................................................ 7
Popular Java-Based Logging APis ................................................................. 7
The Road Ahead ...................................................................................................... 9
Chapter 2 JDK 1. 4 Logging API .................................................... 11
JDK 1.4 Logging API Overview ...................................................................... 11
LogManager Object .............................................................................................. 15
LogRecord Object ................................................................................................ 17
Logger Object ...................................................................................................... 18
Handler ................................................................................................................... 33
Filter Object ...................................................................................................... 51
File-Based Configuration .............................................................................. 55
Formatter Object ................................................................................................ 58
Conclusion ............................................................................................................. 58
Chapter 3 Formatting JDK 1. 4
Logging Information ....................................................
59
Default Formatter Objects ............................................................................ 59
Localization of Logging Messages ............................................................. 68
Writing Custom Formatters ............................................................................ 69
Conclusion ............................................................................................................. 72
v
Contents
Chapter 4 Extending the Logging Framework ........................
73
Configuring the Logging Framework :. ......................................................... 73
Writing Custom Handlers ................................................................................. 83
Remote Logging .................................................................................................... 94
Logging in Practice ....................................................................................... 102
Conclusion ........................................................................................................... 120
Chapter 5 Understanding Apache log4j ................................
121
Installing log4j .............................................................................................. 121
Overview of the log4j Architecture ....................................................... 122
Configuring log4j ............................................................................................ 125
Level Object ....................................................................................................... 136
Logger Object ..................................................................................................... 136
LogManager Object ............................................................................................ 145
Nested Diagnostic Context (NDC) ............................................................. 146
Message Diagnostic Context (MDC) ........................................................... 147
Appender Object ................................................................................................ 149
Filter Object ..................................................................................................... 166
Layout Object ..................................................................................................... 168
ObjectRenderer .................................................................................................. 168
A Complete log4j Example ............................................................................. 169
Conclusion ........................................................................................................... 175
Chapter 6 Formatting Logging Information
in log4j ...............................................................................
177
The Layout Hierarchy ..................................................................................... 177
The Layout Objects in log4j ...................................................................... 178
Conclusion ........................................................................................................... 198
Chapter 7 Advanced Logging with log4j .............................. 199
A Sample Advanced Logging Application ................................................ 200
Logging to a Database with JDBCAppender ............................................ 202
Implementing JMS-Based Logging with JMSAppender .......................... 212
Working with SocketAppender ...................................................................... 223
Logging to Windows NT Event Log with NTEventLogAppender ......... 228
Distributing Logging Information via SMTPAppender ...................... 229
Making Messages Available Through Telnet
with TelnetAppender ................................................................................ 232
Conclusion ........................................................................................................... 232
vi
Contents
Chapter 8 Extending log4j to Create
Custom Logging Components ................................... 235
Creating the Custom WindowAppender ...................................................... 235
Configuring log4j from a Database ......................................................... 243
Custom Logging Framework ............................................................................ 258
More on Filtering ............................................................................................ 270
Error Handling .................................................................................................. 277
Conclusion ........................................................................................................... 284
Chapter 9 Using the Apache Log Tag Library ................. 285
Installing the Log Tag Library ............................................................... 285
A Simple Example of Using the Log Tag Library .............................. 286
Using a Custom Logger with the Log Tag Library ............................ 291
Description of Log Tags .............................................................................. 292
Creating Custom Tags with the Log Tag Library
to Use a Custom Level ............................................................................ 294
Conclusion ........................................................................................................... 298
Chapter 10 Best Practices ............................................................... 299
Obtaining a Logger ......................................................................................... 299
Using Logger Hierarchy ................................................................................. 301
Logging Messages Efficiently .................................................................... 302
Issues with Localization ............................................................................ 304
Using Location Information ........................................................................ 304
Formatting Logging Information ............................................................... 305
Using Renderer Objects ................................................................................. 305
Using Asynchronous Logging ........................................................................ 306
Using Filter Objects ..................................................................................... 306
Using Nested Diagnostic Context ............................................................. 307
Configuration Issues ..................................................................................... 308
Comparing log4j and JDK 1. 4 Logging API ............................................ 309
Conclusion ........................................................................................................... 313
Index ................................................................................................................... 315
vii
About the Author and
Technical Reviewer
About the Author
Samudra Gupta holds a postgraduate degree in information technology and
management from All India Management Association, India, and has around six
years of experience in designing and developing Web-based applications ranging
from research-based projects toe-commerce applications. He started his career
as a research engineer at the Indian Institute of Technology, Kanpur, India, and
he is presently working as an independent Java consultant in the United Kingdom,
architecting and developing several e-commerce-based applications, content
management system software, and retail-based software. Samudra also writes
articles for Java World and Java Developer's Journal, and is a monthly contributor to
Java Boutique (http: I /java boutique. internet. com). When not programming, he
plays a lot of contract bridge.
About the Technical Reviewer
Jeff Heaton is an author, college instructor, and consultant. Jeff lives in Chesterfield,
Missouri. The author of three books and over a dozen journal and magazine
articles, Jeff specializes in Internet, socket- level/ spidering, and artificial intelligence
programming. A Sun-certified Java programmer and a member of the IEEE, Jeff has
a masters degree in information management from Washington University in St. Louis.
viii
Acknowledgments
ALTHOUGH THERE APPEARs only one name on the cover of this book, the credit for
this accomplishment goes to many. I would first of all like to thank everybody in
the Apress family for making a dream come true for me by publishing this book.
Special thanks go to John Zukowski, Editorial Director, Apress, for signing me to
write this book and suggesting many ideas during the course of putting the manu
script together to make this book a better one. Grace Wong, Assistant Publisher,
deserves all the credit for her guidance from the manuscript stage to the production
stage of this book. Tracy Brown Collins and Ami Knox both have done a splendid
job with development and copyediting of this book, contributing so many valuable
ideas and making this book coherent and consistent throughout. Without their
great efforts, many mistakes might have made their way into this book. I also thank
the production team at Apress-Kari Brooks, Production Manager, as well as
Susan Glinert Stevens, Lori Bring, and Ann Rogers-for their commendable job in
the final production of this book.
I am greatly thankful to Jeff Heaton, Technical Reviewer, who suggested
numerous improvements to make this book more accurate and useful. I feel
honored to have his name associated with this book. My heartfelt thanks must also
go to Paul Burden and Ashish Patel, two of the great programmers I have had the
privilege to work with, for contributing their most valuable ideas from the initial
stages of this book.
I take this opportunity to express my deepest gratitude and convey my
most humble regards to Doctor T.V. Prabhakar, Department of Computer Science
and Engineering, Indian Institute of Technology, Kanpur, India, who initiated
me into the world of computer science. Without his most valuable and affectionate
guidance, it just could not have been the same. My special thanks go to
Mr. N. V. Brahmaji Rao, Doctor Amit Neogi, and Doctor Chaitali Roy for encouraging
me throughout my efforts in writing this book. Without their encouragement,
I might not have ventured to do so.
Lastly, my parents and my elder brother (whom I call Dadabhai) have been a
source of constant inspiration and encouragement throughout. I offer them my
sincerest regards, and words cannot express my gratitude to them. In the end, I say
a big "thank you" to all my friends, too many to name individually, and you know
whoyouare.
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