domtreetest.java

对于要加密的文档,www有一套标准,约定用于加密的文档应当组成一定的格式.对于符合这个格式的xml文档,本程序能从中提前rsa加密密钥和明文进行加密.本程序还提供rsa密钥生成接口和加密解密接口.

/**
   @version 1.0 2001-09-01
   @author Cay Horstmann
*/

import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.io.*;
import java.lang.reflect.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.tree.*;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
import java.lang.*;
import org.w3c.dom.*;
import org.xml.sax.*;

/**
   This program displays an XML document as a tree.
*/
public class DOMTreeTest
{
   public static void main(String[] args)
   {
      JFrame frame = new DOMTreeFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.show();
   }
}

/**
   This frame contains a tree that displays the contents of
   an XML document.
*/
class DOMTreeFrame extends JFrame
{
   public DOMTreeFrame()
   {
      setTitle("DOMTreeTest");
      setSize(WIDTH, HEIGHT);

      JMenu fileMenu = new JMenu("File");
      JMenuItem openItem = new JMenuItem("Open");
      openItem.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {

               try
               {
				   openFile();
				}
               catch(TransformerException e)
               {
				}
				catch(IOException r)
				{
					}
            }
         });
      fileMenu.add(openItem);

      JMenuItem exitItem = new JMenuItem("Exit");
      exitItem.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               System.exit(0);
            }
         });
      fileMenu.add(exitItem);

      JMenuBar menuBar = new JMenuBar();
      menuBar.add(fileMenu);
      setJMenuBar(menuBar);
   }

   /**
      Open a file and load the document.
   */
   public void openFile()throws TransformerException,IOException
   {
      JFileChooser chooser = new JFileChooser();
      chooser.setCurrentDirectory(new File("."));

      chooser.setFileFilter(new
         javax.swing.filechooser.FileFilter()
         {
            public boolean accept(File f)
            {
               return f.isDirectory()
                  || f.getName().toLowerCase().endsWith(".xml");
            }
            public String getDescription()
            {
               return "XML files";
            }
         });

      int r = chooser.showOpenDialog(this);
      if (r != JFileChooser.APPROVE_OPTION) return;
      File f = chooser.getSelectedFile();
      saveDocument(f);

   }


	private void saveDocument(File f)throws TransformerException,IOException
	{
		try
			        {
			           if (builder == null)
			           {
			              DocumentBuilderFactory factory
			                 = DocumentBuilderFactory.newInstance();
			              builder = factory.newDocumentBuilder();
			           }

			            doc = builder.parse(f);
			           Element root = doc.getDocumentElement();
						/*String back ="www";
						Element nodeback = doc.createElement(back);
						nodeback.setAttribute("hight","36");
						Text text = doc.createTextNode(back);
						nodeback.appendChild(text);
						root.appendChild(nodeback);
						*/
			           NodeList children = root.getChildNodes();
			           rootFirstTraverse(root);

						Transformer t = TransformerFactory.newInstance().newTransformer();
						t.transform(new DOMSource(doc),new StreamResult(new FileOutputStream(f)));


			        }
			        catch (IOException exception)
			        {
			           JOptionPane.showMessageDialog(this, exception);
			        }
			        catch (ParserConfigurationException exception)
			        {
			           JOptionPane.showMessageDialog(this, exception);
			        }
			        catch (SAXException exception)
			        {
			           JOptionPane.showMessageDialog(this, exception);
		      }

	}

   private void rootFirstTraverse(Node node)
   {
			while(node!=null)
			{


				if(node.getFirstChild()==null)// && node instanceof Node
				{
					try
					{
						Text textNode =(Text)node;
						String text = textNode.getData().trim();
						//move out the blank characters
						if(!text.equals(""))
						{
							//replace here with the function what you used to encription the text
							System.out.println(text);
							System.out.println(proc(text));
							textNode.setNodeValue(proc(text));
						}

					}
					catch(ClassCastException e)
					{
						//process the exception throwed when the node do not have text value
						//System.out.println("此处为空!");
					}

				}//if
				rootFirstTraverse(node.getFirstChild());
				node=node.getNextSibling();

			}//while


	}

	private String proc(String from)
	{
		String result;
		result = from.substring(0,1);
		return result;
	}

	private Document doc;
	private Document newdoc;
   private String name;
   private int size;
   private DocumentBuilder builder;
   private static final int WIDTH = 400;
   private static final int HEIGHT = 400;

}