Determining If an Attribute Was Supplied in a DOM Element : Attribute « XML « Java Tutorial

import java.io.File;

import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class Main {
  public static void main(String[] argv) throws Exception{
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    factory.setValidating(true);
    factory.setExpandEntityReferences(false);

    Document doc = factory.newDocumentBuilder().parse(new File("filename"));
    Element element = doc.getElementById("key1");
    Attr attr = (Attr) element.getAttributeNode("attrName");
    boolean wasSpecified = attr != null && attr.getSpecified();
  }
}

33.22.Attribute
	33.22.1.	Adding and Removing an Attribute in a DOM Element
	33.22.2.	Listing All the Attributes of a DOM Element
	33.22.3.	Removing All the Attributes in a DOM Element
	33.22.4.	Remove all attributes by first making a copy of the attribute names and then using the list to remove the attributes:
	33.22.5.	Determining If an Attribute Was Supplied in a DOM Element
	33.22.6.	Accessing attributes of an element
	33.22.7.	Getting and Setting an Attribute in a DOM Element
	33.22.8.	Extracting attribute values from XML elements