- Sams Teach Yourself XML in 21 Days, Third Edition
- Table of Contents
- About the Author
- Acknowledgments
- We Want to Hear from You!
- Introduction
- Part I: At a Glance
- Day 1. Welcome to XML
- All About Markup Languages
- All About XML
- Looking at XML in a Browser
- Working with XML Data Yourself
- Structuring Your Data
- Creating Well-Formed XML Documents
- Creating Valid XML Documents
- How XML Is Used in the Real World
- Online XML Resources
- Summary
- Q&A
- Workshop
- Day 2. Creating XML Documents
- Choosing an XML Editor
- Using XML Browsers
- Using XML Validators
- Creating XML Documents Piece by Piece
- Creating Prologs
- Creating an XML Declaration
- Creating XML Comments
- Creating Processing Instructions
- Creating Tags and Elements
- Creating CDATA Sections
- Handling Entities
- Summary
- Q&A
- Workshop
- Day 3. Creating Well-Formed XML Documents
- What Makes an XML Document Well-Formed?
- Creating an Example XML Document
- Understanding the Well-Formedness Constraints
- Using XML Namespaces
- Understanding XML Infosets
- Understanding Canonical XML
- Summary
- Q&A
- Workshop
- Day 4. Creating Valid XML Documents: DTDs
- All About DTDs
- Validating a Document by Using a DTD
- Creating Element Content Models
- Commenting a DTD
- Supporting External DTDs
- Handling Namespaces in DTDs
- Summary
- Q&A
- Workshop
- Declaring Attributes in DTDs
- Day 5. Handling Attributes and Entities in DTDs
- Specifying Default Values
- Specifying Attribute Types
- Handling Entities
- Summary
- Q&A
- Workshop
- Day 6. Creating Valid XML Documents: XML Schemas
- Using XML Schema Tools
- Creating XML Schemas
- Dissecting an XML Schema
- The Built-in XML Schema Elements
- Creating Elements and Types
- Specifying a Number of Elements
- Specifying Element Default Values
- Creating Attributes
- Summary
- Q&A
- Workshop
- Day 7. Creating Types in XML Schemas
- Restricting Simple Types by Using XML Schema Facets
- Creating XML Schema Choices
- Using Anonymous Type Definitions
- Declaring Empty Elements
- Declaring Mixed-Content Elements
- Grouping Elements Together
- Grouping Attributes Together
- Declaring all Groups
- Handling Namespaces in Schemas
- Annotating an XML Schema
- Summary
- Q&A
- Workshop
- Part I. In Review
- Well-Formed Documents
- Valid Documents
- Part II: At a Glance
- Day 8. Formatting XML by Using Cascading Style Sheets
- Our Sample XML Document
- Introducing CSS
- Connecting CSS Style Sheets and XML Documents
- Creating Style Sheet Selectors
- Using Inline Styles
- Creating Style Rule Specifications in Style Sheets
- Summary
- Q&A
- Workshop
- Day 9. Formatting XML by Using XSLT
- Introducing XSLT
- Transforming XML by Using XSLT
- Writing XSLT Style Sheets
- Using <xsl:apply-templates>
- Using <xsl:value-of> and <xsl:for-each>
- Matching Nodes by Using the match Attribute
- Working with the select Attribute and XPath
- Using <xsl:copy>
- Using <xsl:if>
- Using <xsl:choose>
- Specifying the Output Document Type
- Summary
- Q&A
- Workshop
- Day 10. Working with XSL Formatting Objects
- Introducing XSL-FO
- Using XSL-FO
- Using XSL Formatting Objects and Properties
- Building an XSL-FO Document
- Handling Inline Formatting
- Formatting Lists
- Formatting Tables
- Summary
- Q&A
- Workshop
- Part II. In Review
- Using CSS
- Using XSLT
- Using XSL-FO
- Part III: At a Glance
- Day 11. Extending HTML with XHTML
- Why XHTML?
- Writing XHTML Documents
- Validating XHTML Documents
- The Basic XHTML Elements
- Organizing Text
- Formatting Text
- Selecting Fonts: <font>
- Comments: <!-->
- Summary
- Q&A
- Workshop
- Day 12. Putting XHTML to Work
- Creating Hyperlinks: <a>
- Linking to Other Documents: <link>
- Handling Images: <img>
- Creating Frame Documents: <frameset>
- Creating Frames: <frame>
- Creating Embedded Style Sheets: <style>
- Formatting Tables: <table>
- Creating Table Rows: <tr>
- Formatting Table Headers: <th>
- Formatting Table Data: <td>
- Extending XHTML
- Summary
- Q&A
- Workshop
- Day 13. Creating Graphics and Multimedia: SVG and SMIL
- Introducing SVG
- Creating an SVG Document
- Creating Rectangles
- Adobe's SVG Viewer
- Using CSS Styles
- Creating Circles
- Creating Ellipses
- Creating Lines
- Creating Polylines
- Creating Polygons
- Creating Text
- Creating Gradients
- Creating Paths
- Creating Text Paths
- Creating Groups and Transformations
- Creating Animation
- Creating Links
- Creating Scripts
- Embedding SVG in HTML
- Introducing SMIL
- Summary
- Q&A
- Workshop
- Day 14. Handling XLinks, XPointers, and XForms
- Introducing XLinks
- Beyond Simple XLinks
- Introducing XPointers
- Introducing XBase
- Introducing XForms
- Summary
- Workshop
- Part III. In Review
- Part IV: At a Glance
- Day 15. Using JavaScript and XML
- Introducing the W3C DOM
- Introducing the DOM Objects
- Working with the XML DOM in JavaScript
- Searching for Elements by Name
- Reading Attribute Values
- Getting All XML Data from a Document
- Validating XML Documents by Using DTDs
- Summary
- Q&A
- Workshop
- Day 16. Using Java and .NET: DOM
- Using Java to Read XML Data
- Finding Elements by Name
- Creating an XML Browser by Using Java
- Navigating Through XML Documents
- Writing XML by Using Java
- Summary
- Q&A
- Workshop
- Day 17. Using Java and .NET: SAX
- An Overview of SAX
- Using SAX
- Using SAX to Find Elements by Name
- Creating an XML Browser by Using Java and SAX
- Navigating Through XML Documents by Using SAX
- Writing XML by Using Java and SAX
- Summary
- Q&A
- Workshop
- Day 18. Working with SOAP and RDF
- Introducing SOAP
- A SOAP Example in .NET
- A SOAP Example in Java
- Introducing RDF
- Summary
- Q&A
- Workshop
- Part IV. In Review
- Part V: At a Glance
- Day 19. Handling XML Data Binding
- Introducing DSOs
- Binding HTML Elements to HTML Data
- Binding HTML Elements to XML Data
- Binding HTML Tables to XML Data
- Accessing Individual Data Fields
- Binding HTML Elements to XML Data by Using the XML DSO
- Binding HTML Tables to XML Data by Using the XML DSO
- Searching XML Data by Using a DSO and JavaScript
- Handling Hierarchical XML Data
- Summary
- Q&A
- Workshop
- Day 20. Working with XML and Databases
- XML, Databases, and ASP
- Storing Databases as XML
- Using XPath with a Database
- Introducing XQuery
- Summary
- Q&A
- Workshop
- Day 21. Handling XML in .NET
- Creating and Editing an XML Document in .NET
- From XML to Databases and Back
- Reading and Writing XML in .NET Code
- Using XML Controls to Display Formatted XML
- Creating XML Web Services
- Summary
- Q&A
- Workshop
- Part V. In Review
- Appendix A. Quiz Answers
- Quiz Answers for Day 1
- Quiz Answers for Day 2
- Quiz Answers for Day 3
- Quiz Answers for Day 4
- Quiz Answers for Day 5
- Quiz Answers for Day 6
- Quiz Answers for Day 7
- Quiz Answers for Day 8
- Quiz Answers for Day 9
- Quiz Answers for Day 10
- Quiz Answers for Day 11
- Quiz Answers for Day 12
- Quiz Answers for Day 13
- Quiz Answers for Day 14
- Quiz Answers for Day 15
- Quiz Answers for Day 16
- Quiz Answers for Day 17
- Quiz Answers for Day 18
- Quiz Answers for Day 19
- Quiz Answers for Day 20
- Quiz Answers for Day 21
Working with XML Data Yourself
Say that you want to extract the data from an XML document yourself, and to work with that data, rather than simply telling a browser how to display it. For example, suppose you want to extract the text from our <heading> element:
<?xml version="1.0" encoding="UTF-8"?> <?xml-stylesheet type="text/css" href="ch01_04.css"?> <document> <heading> Hello From XML </heading> <message> This is an XML document! </message> </document>
One way of gaining access to that data in a browser is to use JavaScript, which browsers like Internet Explorer and Netscape Navigator support. We'll work through that process step by step in Day 15, "Using JavaScript and XML," but you can see a sample HTML page with embedded JavaScript that will do the trick in Listing 1.5.
Example 1.5. Extracting Data from an XML Document Using JavaScript (ch01_05.html)
<HTML> <HEAD> <TITLE> Retrieving data from an XML document </TITLE> <XML ID="firstXML" SRC="ch01_02.xml"></XML> <SCRIPT LANGUAGE="JavaScript"> function getData() { xmldoc= document.all("firstXML").XMLDocument; nodeDoc = xmldoc.documentElement; nodeHeading = nodeDoc.firstChild; outputMessage = "Heading: " + nodeHeading.firstChild.nodeValue; message.innerHTML=outputMessage; } </SCRIPT> </HEAD> <BODY> <CENTER> <H1> Retrieving data from an XML document </H1> <DIV ID="message"></DIV> <P> <INPUT TYPE="BUTTON" VALUE="Read the heading" ONCLICK="getData()"> </CENTER> </BODY> </HTML>
When you open this example in Internet Explorer, it displays a button with the caption "Read the heading", as you see in Figure 1.5. When you click that button, the JavaScript reads the text in the <heading> element in our sample XML document, ch01_02.xml, and displays that text, as you see in the figure. In this way, we've been able to extract data from an XML document—and when you've extracted your data from an XML document, you're free to work on it as you like.
Figure 1.5 Extracting data from an XML document in Internet Explorer.
We'll also take a look at using the Java programming language to handle XML in Day 16, "Using Java and .NET: DOM," and Day 17, "Using Java and .NET: SAX." Java has all kinds of built-in support for working with XML, and you can see a sample Java program in Listing 1.6. Like our JavaScript example, this example reads the text content of the <heading> element in our sample XML document, ch01_02.xml, and displays that text.
Example 1.6. Extracting Data from an XML Document Using Java (ch01_06.java)
import javax.xml.parsers.*; import org.w3c.dom.*; import java.io.*; public class ch01_06 { static public void main(String[] argv) { try { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db = null; try { db = dbf.newDocumentBuilder(); } catch (ParserConfigurationException pce) {} Document doc = null; doc = db.parse("ch01_02.xml"); for (Node node = doc.getDocumentElement().getFirstChild(); node != null; node = node.getNextSibling()) { if (node instanceof Element) { if (node.getNodeName().equals("heading")) { StringBuffer buffer = new StringBuffer(); for (Node subnode = node.getFirstChild(); subnode != null; subnode = subnode. getNextSibling()){ if (subnode instanceof Text) { buffer.append(subnode.getNodeValue()); } } System.out.println(buffer.toString()); } } } } catch (Exception e) { e.printStackTrace(); } } }
When you run this program (see Day 16 for the details), the output looks like this:
%java ch01_06 Hello From XML
As you can see, it's possible to extract data from an XML document, so someone else can write such a document using tags you both agree on, send you that document over the Internet, and you can extract the data you need from the document by searching for elements with specific names. There are thousands of Web-based applications these days, and they've sent and interpreted thousands of XML documents in the time it took you to read this sentence.