Java XML Tutorial - Java Document.getDocumentElement()

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Syntax

Document.getDocumentElement() has the following syntax.

Element getDocumentElement()

Example

In the following code shows how to use Document.getDocumentElement() method.

import static org.w3c.dom.Node.ATTRIBUTE_NODE;
import static org.w3c.dom.Node.CDATA_SECTION_NODE;
import static org.w3c.dom.Node.COMMENT_NODE;
import static org.w3c.dom.Node.DOCUMENT_TYPE_NODE;
import static org.w3c.dom.Node.ELEMENT_NODE;
import static org.w3c.dom.Node.ENTITY_NODE;
import static org.w3c.dom.Node.ENTITY_REFERENCE_NODE;
import static org.w3c.dom.Node.NOTATION_NODE;
import static org.w3c.dom.Node.PROCESSING_INSTRUCTION_NODE;
import static org.w3c.dom.Node.TEXT_NODE;
/*w w  w .j  a v  a  2 s . c om*/
import java.io.IOException;
import java.io.StringReader;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.DocumentType;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

public class Main {
  public static void main(String args[]) {
    DocumentBuilderFactory builderFactory = DocumentBuilderFactory.newInstance();
    builderFactory.setNamespaceAware(true);       // Set namespace aware
    builderFactory.setValidating(true);           // and validating parser feaures
    builderFactory.setIgnoringElementContentWhitespace(true); 
    
    DocumentBuilder builder = null;
    try {
      builder = builderFactory.newDocumentBuilder();  // Create the parser
    } catch(ParserConfigurationException e) {
      e.printStackTrace();
    }
    Document xmlDoc = null;

    try {
      xmlDoc = builder.parse(new InputSource(new StringReader(xmlString)));

    } catch(SAXException e) {
      e.printStackTrace();

    } catch(IOException e) {
      e.printStackTrace();
    }
    DocumentType doctype = xmlDoc.getDoctype();       
    if(doctype == null) {                             
      System.out.println("DOCTYPE is null");
    } else {                                          
      System.out.println("DOCTYPE node:\n" + doctype.getInternalSubset());
    }

    System.out.println("\nDocument body contents are:");
    listNodes(xmlDoc.getDocumentElement(),"");         // Root element & children
  }
  static void listNodes(Node node, String indent) {
    String nodeName = node.getNodeName();
    System.out.println(indent+" Node: " + nodeName);
    short type = node.getNodeType();
    System.out.println(indent+" Node Type: " + nodeType(type));
    if(type == TEXT_NODE){
      System.out.println(indent+" Content is: "+((Text)node).getWholeText());
    }
    
    NodeList list = node.getChildNodes();       
    if(list.getLength() > 0) {                  
      System.out.println(indent+" Child Nodes of "+nodeName+" are:");
      for(int i = 0 ; i<list.getLength() ; i++) {
        listNodes(list.item(i),indent+"  ");     
      }
    }         
  }

  static String nodeType(short type) {
    switch(type) {
      case ELEMENT_NODE:                return "Element";
      case DOCUMENT_TYPE_NODE:          return "Document type";
      case ENTITY_NODE:                 return "Entity";
      case ENTITY_REFERENCE_NODE:       return "Entity reference";
      case NOTATION_NODE:               return "Notation";
      case TEXT_NODE:                   return "Text";
      case COMMENT_NODE:                return "Comment";
      case CDATA_SECTION_NODE:          return "CDATA Section";
      case ATTRIBUTE_NODE:              return "Attribute";
      case PROCESSING_INSTRUCTION_NODE: return "Attribute";
    }
    return "Unidentified";
  }

  static String xmlString ="<?xml version=\"1.0\"?>" +
      "  <!DOCTYPE address" +
      "  [" +
      "     <!ELEMENT address (buildingnumber, street, city, state, zip)>" +
      "     <!ATTLIST address xmlns CDATA #IMPLIED>" +
      "     <!ELEMENT buildingnumber (#PCDATA)>" +
      "     <!ELEMENT street (#PCDATA)>" +
      "     <!ELEMENT city (#PCDATA)>" +
      "     <!ELEMENT state (#PCDATA)>" +
      "     <!ELEMENT zip (#PCDATA)>" +
      "  ]>" +
      "" +
      "  <address>" +
      "    <buildingnumber> 29 </buildingnumber>" +
      "    <street> South Street</street>" +
      "    <city>Vancouver</city>" +
      "" +
      "    <state>BC</state>" +
      "    <zip>V6V 4U7</zip>" +
      "  </address>";
}

The code above generates the following result.

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