In this example we shall show you how to get an Element’s Attributes using SAX XML parsing. Simple API for XML (SAX) is an event-driven, serial-access mechanism for accessing XML documents. It is frequently used by servlets and network-oriented programs that need to transmit and receive XML documents, because it is the fastest and least memory-intensive mechanism that is currently available for dealing with XML documents, other than the Streaming API for XML (StAX). We have created a Class, GetElementAttributesInSAXXMLParsing that is a handler that extends the DefaultHandler and overrides its startElement(String uri, String localName, String qName, Attributes attributes) API method. The basic steps of the example are described below:
- Create a new instance of the
GetElementAttributesInSAXXMLParsingclass. - Obtain a new instance of a SAXParserFactory, that is a factory API that enables applications to configure and obtain a SAX based parser to parse XML documents.
- Set the parser produced by this code so as not to validate documents as they are parsed, using
setValidating(boolean validating)API method of SAXParserFactory with validating set to false. - Create a new instance of a SAXParser, using
newSAXParser()API method of SAXParserFactory. - Use
parse(File f, DefaultHandler dh)API method of SAXParser to parse the content of the specified XML file, using the specified handler of the example. The handler that we have implemented, overrides thestartElement(String uri, String localName, String qName, Attributes attributes)API method of DefaultHandler. In this method, for each one of the given Attributes it takes its qualified (prefixed) name, its value, namespace URI and local name, usinggetQName(int index),getValue(int index),getURI(int index)andgetLocalName(int index)API methods of Attributes,
as described in the code snippet below.
package com.javacodegeeks.snippets.core;
import java.io.File;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
public class GetElementAttributesInSAXXMLParsing extends DefaultHandler {
public static void main(String[] args) throws Exception {
DefaultHandler handler = new GetElementAttributesInSAXXMLParsing();
SAXParserFactory factory = SAXParserFactory.newInstance();
factory.setValidating(false);
SAXParser parser = factory.newSAXParser();
parser.parse(new File("in.xml"), handler);
}
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
// get the number of attributes in the list
int length = attributes.getLength();
// process each attribute
for (int i=0; i<length; i++) {
// get qualified (prefixed) name by index
String name = attributes.getQName(i);
System.out.println("Name:" + name);
// get attribute's value by index.
String value = attributes.getValue(i);
System.out.println("Value:" + value);
// get namespace URI by index (if parser is namespace-aware)
String nsUri = attributes.getURI(i);
System.out.println("NS Uri:" + nsUri);
// get local name by index
String lName = attributes.getLocalName(i);
System.out.println("Local Name:" + lName);
}
}
}
Input:
<?xml version="1.0" encoding="UTF-8" ?> <response code="200" description="OK"> <date zone="UTC">2008-11-07</date> <title>Exchange rates for 2008-11-07</title> </response>
Output:
Name:code
Value:200
NS Uri:
Local Name:code
Name:description
Value:OK
NS Uri:
Local Name:description
Name:zone
Value:UTC
NS Uri:
Local Name:zone
This was an example of how to get an Element’s Attributes using SAX XML parsing in Java.
