How to read XML file in Java

This sample code reads the XML file using DOM parser. DOM parser loads the XML file into the memory and makes an object model of it. This Object modal can be traversed to get its elements.

This code will parse the following MyXMLFile.xml file and print its elements to the console.



XML file: MyXMLFile.xml

<?xml version="1.0"?>
<company>
  <employee>
    <firstname>Tom</firstname>
    <lastname>Cruise</lastname>
  </employee>
  <employee>
    <firstname>Paul</firstname>
    <lastname>Enderson</lastname>
  </employee>
  <employee>
    <firstname>George</firstname>
    <lastname>Bush</lastname>
  </employee>
</company>

import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node; 
import org.w3c.dom.NodeList; 

public class XMLReader {            
   public static void main(String argv[]) {               
      try {                  
        File file = new File("c:\MyXMLFile.xml");                 
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 
        DocumentBuilder db = dbf.newDocumentBuilder(); 
        Document doc = db.parse(file); 
        doc.getDocumentElement().normalize(); 
        System.out.println("Root element " + doc.getDocumentElement().getNodeName()); 
        NodeList nodeLst = doc.getElementsByTagName("employee"); 
        System.out.println("Information of all employees"); 
        for (int s = 0; s < nodeLst.getLength(); s++) { 
           Node fstNode = nodeLst.item(s);
          if (fstNode.getNodeType() == Node.ELEMENT_NODE) { 
              Element fstElmnt = (Element) fstNode; 
              NodeList fstNmElmntLst = fstElmnt.getElementsByTagName("firstname"); 
              Element fstNmElmnt = (Element) fstNmElmntLst.item(0); 
              NodeList fstNm = fstNmElmnt.getChildNodes(); 
              System.out.println("First Name : " + ((Node) fstNm.item(0)).getNodeValue()); 
              NodeList lstNmElmntLst = fstElmnt.getElementsByTagName("lastname"); 
              Element lstNmElmnt = (Element) lstNmElmntLst.item(0); 
              NodeList lstNm = lstNmElmnt.getChildNodes(); 
              System.out.println("Last Name : " + ((Node) lstNm.item(0)).getNodeValue()); 
           }
        }
     } catch (Exception e) { 
        e.printStackTrace(); 
     } 
   } 
} 

Converting Between Strings (Unicode) and Other Character Set Encodings

Many network protocols and files store their characters with a byte-oriented character set such as ISO-8859-1 (ISO-Latin-1). However, Java's native character encoding is Unicode. This example demonstrates how to convert ISO-8859-1 encoded bytes in a ByteBuffer to a string in a CharBuffer and visa versa.

// Create the encoder and decoder for ISO-8859-1  
Charset charset = Charset.forName("ISO-8859-1");
CharsetDecoder decoder = charset.newDecoder();
CharsetEncoder encoder = charset.newEncoder();
try {  
    // Convert a string to ISO-LATIN-1 bytes in a ByteBuffer  
    // The new ByteBuffer is ready to be read.  
    ByteBuffer bbuf = encoder.encode(CharBuffer.wrap("a string"));  
    // Convert ISO-LATIN-1 bytes in a ByteBuffer to a character ByteBuffer and then to a string.  
    // The new ByteBuffer is ready to be read.  
    CharBuffer cbuf = decoder.decode(bbuf);  
    String s = cbuf.toString();  
} catch (CharacterCodingException e) {  
}

In the example above, the encoding and decoding methods created new ByteBuffers into which to encode or decoding the data. Moreover, the newly allocated ByteBuffers are non-direct. The encoder and decoder provide methods that use a supplied ByteBuffer rather than create one. Here's an example that uses these methods:

// Create a direct ByteBuffer.    
// This buffer will be used to send and recieve data from channels.  
ByteBuffer bbuf = ByteBuffer.allocateDirect(1024);  
// Create a non-direct character ByteBuffer  
CharBuffer cbuf = CharBuffer.allocate(1024);  
// Convert characters in cbuf to bbuf  
encoder.encode(cbuf, bbuf, false);  
// flip bbuf before reading from it  
bbuf.flip();  
// Convert bytes in bbuf to cbuf  
decoder.decode(bbuf, cbuf, false);  
// flip cbuf before reading from it  
cbuf.flip();

Hope you think it's helpful :D - this post i found in www.exampledepot.com