Introduction

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Welcome to Professional Java Servlets 2.3. This book is designed to show you how we can use Java Servlet technology to create powerful and portable enterprise components for use in web applications.

The web tier has emerged as the point of interaction between distributed business services, and so in this book we concentrate on using servlets as the engine behind web applications and component frameworks. We'll see how we can use servlets to control the flow of execution of applications, keep track of users of an application, intercept and modify requests and responses, and interact with web services.

With the development of the 2.3 version of the Servlet specification (finalized in September 2001), the expert group have made a number of changes including:

• Addition of Filtering

• Inclusion of listening or lifecycle events

• J2SE 1.2 required as underlying platform for web containers

• Incorporation of the Javadoc API definitions into the specifications

• Internationalization improvements

• Java Archive (JAR) dependencies

• Classloader improvements

• Various other changes such as new improved error attributes, new security attributes affecting HTTPS requests, and finally

• New classes and method changes and deprecation of the javax.servlet.http.HttpUtils class.

The Servlets 2.3 API specification is also a key component in the Java 2 Patform, Enterprise Edition (J2EE) 1.3 specification, and as we will see in this book, plays a critical role as a controller in application architected in the J2EE platform.

As we go along, we'll explain these concepts thouroughly, using plenty of complete, working examples to demonstrate their use.

Who is this Book For?

This book is aimed at developers who are familiar with the Java language and the core Java APIs. It is assumed that readers are familiar with some basic HTML and XML - although this isn't essential. We'll be using the latest specification of Java Servlet technology - version 2.3.

Servlets are rarely used in isolation but this book does not claim to be exhaustive in all areas, particularly in relation to other Java technologies and APIs such as JDBC, JNDI, and JavaServer Pages. Professional Java Server Programming J2EE 1.3 Edition (ISBN 1-861005-37-7) provides an excellent introduction to the whole J2EE platform.

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