Lab 6B

Building an XML Server

XML Server Architecture

Instructions

	Tool	Official Site	Local Cache	Size	Installation Procedure
1	Java Development Kit (JDK) Java Runtime Environment (JRE) Compiler, debugger, other tools Java 2 SDK, Standard Edition (J2SE) Software Development Kit (SDK)	j2sdk-1_3_1-win.exe from java.sun.com	j2sdk-1_3_1-win.exe from keller.com	32.8 MB	Run the downloaded file directly; it self-extracts. Install it at C:\tools\jdk1.3.1. Reboot. Problems? Here are details.
2	Tomcat servlet wrapper An enhanced Apache-like web server Includes the Java API for XML Processing (JAXP, in a Java source file named javax.xml) Class libraries: a parser API, a transformer (stylesheet) API, W3C's DOM, XML.org's SAX Documented here	jakarta-tomcat-3.3.1.zip from apache.org	jakarta-tomcat-3.3.1.zip from keller.com	4.7 MB	Unzip it into C:\tools\jakarta-tomcat-3.3.1
3	The Xalan XSLT processor Applies XSLT stylesheets to XML data Includes the Xerces XML parser Documented here	xalan-j_2_4_D1-bin.zip from apache.org	xalan-j_2_4_D1-bin.zip from keller.com	9.3 MB	Unzip it into C:\tools\xalan-j_2_4_D1

Copy the following files from

C:\tools\xalan-j_2_4_D1\bin

to

C:\tools\jakarta-tomcat-3.3.1\lib\apps

JAR Name	Description
xalan.jar	XSL processor
xalanservlet.jar	sample servlets
xml-apis.jar	JAXP (see below)
xercesImpl.jar	JAXP-compliant XML parser

• In a DOS (command prompt) window, enter:

  set JAVA_HOME=C:\tools\jdk1.3.1
  cd C:\tools\jakarta-tomcat-3.3.1\bin\
  startup

• Verify that it's running by opening http://localhost:8080/ in your browser.

• Keep an eye on the server log. It is displayed in a window entitled Tomcat 3.3 that pops up when you run Tomcat. Observe that requests and errors are logged.

• It is named servlet.XSLTServletWithParams

• It is one of several sample servlets in xalanservlet.jar which is included with Xalan

• Documented here

• View a servlet-preprocessed XML document in your browser by entering (as a single string) the URL:

  http://localhost:8080/servlet/servlet.XSLTServletWithParams?
  URL=file:/tools/xalan-j_2_4_D1/samples/SimpleTransform/birds.xml&
  xslURL=file:/tools/xalan-j_2_4_D1/samples/SimpleTransform/birds.xsl

  ...or simply click here.

• Substitute for the local stylesheet and XML data file the following URLs:

  • http://www.keller.com/downloads/xml/lab6b.xml

  • http://www.keller.com/downloads/xml/lab6b.xsl

  That is, in place of file:/... substitute http://...

  The modified URL becomes:

  http://localhost:8080/servlet/servlet.XSLTServletWithParams?
  URL=http://www.keller.com/downloads/xml/lab6b.xml&
  xslURL=http://www.keller.com/downloads/xml/lab6b.xsl

  Save yourself some typing by clicking here.

  This demonstrates that the various components of an application can be distributed around the web while the stylesheet processing is done on the local server.

The directory in which to install these files is:

C:\tools\xalan-j_2_4_D1\samples\SimpleTransform

Caveat: Xalan is fussy about the stylesheet namespace. Be sure to declare it as:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">

Read the Java source code for servlet.XSLTServletWithParams to get an idea of the architecture of an XML-generating program. The full pathname of this file is:

C:\tools\xalan-j_2_4_D1\samples\servlet\XSLTServletWithParams.java

Observe that the crucial line of code -- in which the stylesheet transformation is done -- is line 130:

transformer.transform(xmlSource, new StreamResult(out));