Chapter12.XML

Chapter 12. XML

• Introducing XML

• Parsing an XML Document

• Validating XML Documents

• Locating Information with XPath

• Using Namespaces

• Using the SAX Parser

• Generating XML Documents

• XSL Transformations

The preface of the book Essential XML by Don Box, et al. [Addison-Wesley 2000] states only half-jokingly: "The Extensible Markup Language (XML) has replaced Java, Design Patterns, and Object Technology as the software industry's solution to world hunger." Indeed, as you will see in this chapter, XML is a very useful technology for describing structured information. XML tools make it easy to process and transform that information. However, XML is not a silver bullet. You need domain-specific standards and code libraries to use it effectively. Moreover, far from making Java technology obsolete, XML works very well with Java. Essentially all important XML libraries have been implemented first in the Java programming language, and many of them are unavailable in any other programming language. Since the late 1990s, IBM, Apache, and others have been instrumental in producing high-quality Java libraries for XML processing. Starting with JDK 1.4, Sun has integrated the most important libraries into the Java 2 Platform, Standard Edition.

NOTE

You can download the Java API for XML Processing (JAXP) library from http://java.sun.com/xml to add the same XML processing capabilities to older Java installations.

This chapter introduces XML and covers the XML features of the Java library. As always, we point out along the way when the hype surrounding XML is justified and when you have to take it with a grain of salt and solve your problems the old-fashioned way, through good design and code.