The javax.xml.parsers.DocumentBuilderFactory Class

Super Class : java.lang.Object.

Members

Overview

This class provides the factory that enables applications to create a parser to parse XML documents and also create DOM Document. This class is not thread safe and user should take care regarding creation of DocumentBuilderFactory and it is suggested to have one instance per Thread. This class is generally used to get javax.xml.parsers.DocumentBuilder instance and use that to produce a org.w3c.dom.Document.

Application code does not deal directly with specific parse implementation such as Xerces or Crimson. Instead you write code against abstract classes provided by JAXP apis. This level of indirection allows you to choose and pick among different implementation without even recompiling your application.

Method Overviews

Important methods of this class are newInstance(),   newDocumentBuilder(), setNamespaceAware(boolean awareness) and setValidating(boolean validating).

Example of newInstance()

This method is used to create an instance of DocumentBuilderFactory. This is a abstract class and newInstance method uses the lookup method to load appropriate DocumentBuilderFactory. Generally

·        Use the value of javax.xml.parsers.DocumentBuilderFactory system property.

You can set the system property as {your factory class} = your factory class impl (It  may be org.apache.crimson.jaxp.DocumentBuilderFactoryImpl or org.apache.xerces.jaxp.DocumentBuilderFactoryImpl).

·        IfJRE/lib/jaxp.properties exists, then look for a javax.xml.parsers.DocumentBuilderFactory = Implementation entry in the file.

·        Use a JAR file service provider to look for a file called META-INF/services/ javax.xml.parsers.DocumentBuilderFactory in any jar file on the CLASSPATH.

·        Use default javax.xml.parsers.DocumentBuilderFactory instance(org.apache.crimson.jaxp.DocumentBuilderFactoryImpl will be used as a default implementation).

By default, it loads org.apache.crimson.jaxp.DocumentBuilderFactoryImpl instance.

Example of newDocumentBuilder()

This method creates an instance of javax.xml.parsers.DocumentBuilder. You can use newDocument() method to create a org.w3c.dom.Document interface or use parse() method to parse xml from various xml sources. These input sources are InputStreams, Files, URLs, and SAX InputSources.

Example of setValidating(boolean)

This method is used to validate an xml document during parsing. By default it is false.

Example of setNamespaceAware(boolean). This method is used to provide namespace aware for the parser and by default it is false.

Example of How to Create DocumentBuilderFactory

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.DocumentBuilder;

import java.io.File;

public class MainClass {

  public MainClass() {

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

    try{

      DocumentBuilder docBuilder = factory.newDocumentBuilder();

      docBuilder.parse(Inputsource);

    }catch(javax.xml.parsers.ParserConfigurationException e){

      e.printStackTrace();

    }catch(java.io.IOException e){

      e.printStackTrace();

    }catch(org.xml.sax.SAXException e){

      e.printStackTrace();

    }

  }

  public static void main(String args[]){

  MainClass mainClass = new MainClass();

  }

}