XML FAQ   

This is the FAQ page for the XML and Related Technologies forum. Contributions are welcome. Also see XmlLinks.

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Q: The characters() method in my SAX parser doesn't return all the text (or is called more than once). What gives?

Here's what the javadocs of that method say: SAX parsers may return all contiguous character data in a single chunk, or they may split it into several chunks. William Brogden explains :

The characters() method may be called any number of times within a single element because the SAX parser only handles one bufferload of input characters at a time. It is up to the programmer to assemble the text properly.

I normally have a StringBuffer or StringBuilder reference that gets a new instance when the appropriate startElement() is hit and gets additions from each call to the characters() method. When endElement() occurs I use toString() to get the assembled characters and then work on the logic.

JavaDoc:org.xml.sax.ContentHandler

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Java Code Examples

• HowToValidateXmlAgainstSchema
• HowToValidateXmlAgainstAnySchema (or DTD or Relax-NG)
• HowToPrettyPrintXmlWithXsl
• HowToPrettyPrintXmlWithJava
• DocumentToFile
• DocumentToString
• DocumentToByteArray
• StringToDocument
• ByteArrayToDocument
• GetElementValueByNameUsingDom
• GetNodeValue

Various XML-handling code examples can be found on the Example Depot site (see javax.xml.parsers, javax.xml.transform, javax.xml.transform.sax, org.w3c.dom and org.xml.sax at the bottom of the page).

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Articles and introductions

General

• Introduction to XML
• A Technical Introduction to XML

Specifically about Java

• Introduction to XML processing in Java
• Introduction to DOM and SAX Parsing
• Introduction to XML and XML processing in Java
• Using JAXP to process XML
• Creating XML using DOM
• Using JAXP to validate an XML document
• Load, Save and Filter XML Documents Using the DOM Level 3 API
• What's new in JAXP 1.3
• JAXP 1.4 Release Notes
• JAXP FAQ
• Another introduction to JAXP XPath processing
• An Introduction to StAX (Streaming API for XML) (new in JAXP 1.4 and Java 6)
• XQJ - a standard API for XQuery processing in Java; another introduction to XQJ

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Software

• XML Hammer "is a free and open-source tool that simplifies elementary XML actions like checking for well-formedness, validation, transformation and XPath searches using any JAXP implementation".
• Xerces is a powerful XML parser that is now part of the JRE.
• Crimson is a (now obsolete) XML parser that supports DOM, SAX and JAXP 1.1. It was used in the JRE before the switch to Xerces, and is a useful example for studying the inner workings of an XML parser.
• dom4j, JDOM and XOM are alternative Java DOM APIs.
• Xalan and Saxon are XSL-T processors.
• Apache FOP is an XSL-FO processor that can output numerous formats, including PDF, PS, PCL, AFP, Print, AWT and PNG, and to a lesser extent, RTF and TXT.
• Apache Santuario implements XML Signature and XML Encryption
• JAXB is a Java <--> XML binding library.
• Apache Commons Digester is an XML --> Java mapping library
• NekoHTML, HtmlCleaner, jTidy and TagSoup are libraries that clean up HTML and transform it to XML (thus allowing DOM and SAX to work with them).
• a list of open source XML Diff and Patch tools

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CategoryFaq XmlLinks