java文本文件加密解密类

[java]代码库

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;

/**
 * 文本文件加密解密类
 *
 * 文件名：FileEncrypter.java JDK：1.40以上 说明：文件加密 加密方法：三重DES加密
 * 加密过程：对选中的文件加密后在同文件夹下生成一个增加了".tdes" 扩展名的加密文件
 *
 * 解密过程：对选中的加密文件（必须有".tdes"扩展名）进行解密
 */
public class Test extends JFrame
{
	public static final int WIDTH = 550;
	public static final int HEIGHT = 200;

	public static void main ( String args[] )
	{
		Test fe = new Test();
		fe.show();
	}

	Test()
	{
		this.setSize ( WIDTH, HEIGHT );
		this.setDefaultCloseOperation ( JFrame.EXIT_ON_CLOSE );
		this.setResizable ( false );
		Toolkit tk = Toolkit.getDefaultToolkit();
		Dimension screenSize = tk.getScreenSize();
		this.setLocation ( ( screenSize.width - WIDTH ) / 2,
		                   ( screenSize.height - HEIGHT ) / 2 );
		this.setTitle ( "文件加密器(TriDES)" );
		Container c = this.getContentPane();
		c.setLayout ( new FlowLayout() );

		final FilePanel fp = new FilePanel ( "文件选择" );
		c.add ( fp );

		final KeyPanel pp = new KeyPanel ( "密码" );
		c.add ( pp );

		JButton jbE = new JButton ( "加密" );
		c.add ( jbE );
		jbE.addActionListener ( new ActionListener()
		{
			public void actionPerformed ( ActionEvent event )
			{
				File file = new File ( fp.getFileName() );
				if ( file.exists() )
					encrypt ( file.getAbsoluteFile(), pp.getKey() );
				else
					JOptionPane.showMessageDialog ( null, "请选择文件！", "提示",
					                                JOptionPane.OK_OPTION );
			}
		} );
		JButton jbD = new JButton ( "解密" );
		c.add ( jbD );
		jbD.addActionListener ( new ActionListener()
		{
			public void actionPerformed ( ActionEvent event )
			{
				File file = new File ( fp.getFileName() );
				if ( file.exists() )
					decrypt ( file.getAbsoluteFile(), pp.getKey() );
				else
					JOptionPane.showMessageDialog ( null, "请选择文件！", "提示",
					                                JOptionPane.OK_OPTION );
			}
		} );
	}

	/**
	 * 加密函数 输入： 要加密的文件，密码（由0-F组成，共48个字符，表示3个8位的密码）如：
	 * AD67EA2F3BE6E5ADD368DFE03120B5DF92A8FD8FEC2F0746 其中： AD67EA2F3BE6E5AD
	 * DES密码一 D368DFE03120B5DF DES密码二 92A8FD8FEC2F0746 DES密码三 输出：
	 * 对输入的文件加密后，保存到同一文件夹下增加了".tdes"扩展名的文件中。
	 */
	private void encrypt ( File fileIn, String sKey )
	{
		try
		{
			if ( sKey.length() == 48 )
			{
				byte[] bytK1 = getKeyByStr ( sKey.substring ( 0, 16 ) );
				byte[] bytK2 = getKeyByStr ( sKey.substring ( 16, 32 ) );
				byte[] bytK3 = getKeyByStr ( sKey.substring ( 32, 48 ) );

				FileInputStream fis = new FileInputStream ( fileIn );
				byte[] bytIn = new byte[ ( int ) fileIn.length() ];
				for ( int i = 0; i < fileIn.length(); i++ )
				{
					bytIn[i] = ( byte ) fis.read();
				}
				// 加密
				byte[] bytOut = encryptByDES (
				                    encryptByDES ( encryptByDES ( bytIn, bytK1 ), bytK2 ), bytK3 );
				String fileOut = fileIn.getPath() + ".tdes";
				FileOutputStream fos = new FileOutputStream ( fileOut );
				for ( int i = 0; i < bytOut.length; i++ )
				{
					fos.write ( ( int ) bytOut[i] );
				}
				fos.close();
				JOptionPane.showMessageDialog ( this, "加密成功！", "提示",
				                                JOptionPane.OK_OPTION );
			}
			else
				JOptionPane.showMessageDialog ( this, "密码长度必须等于48！", "错误信息",
				                                JOptionPane.ERROR_MESSAGE );
		}
		catch ( Exception e )
		{
			e.printStackTrace();
		}
	}

	/**
	 * 解密函数 输入： 要解密的文件，密码（由0-F组成，共48个字符，表示3个8位的密码）如：
	 * AD67EA2F3BE6E5ADD368DFE03120B5DF92A8FD8FEC2F0746 其中： AD67EA2F3BE6E5AD
	 * DES密码一 D368DFE03120B5DF DES密码二 92A8FD8FEC2F0746 DES密码三 输出：
	 * 对输入的文件解密后，保存到用户指定的文件中。
	 */
	private void decrypt ( File fileIn, String sKey )
	{
		try
		{
			if ( sKey.length() == 48 )
			{
				String strPath = fileIn.getPath();
				if ( strPath.substring ( strPath.length() - 5 ).toLowerCase()
				        .equals ( ".tdes" ) )
					strPath = strPath.substring ( 0, strPath.length() - 5 );
				else
				{
					JOptionPane.showMessageDialog ( this, "不是合法的加密文件！", "提示",
					                                JOptionPane.OK_OPTION );
					return;
				}
				JFileChooser chooser = new JFileChooser();
				chooser.setCurrentDirectory ( new File ( "." ) );
				chooser.setSelectedFile ( new File ( strPath ) );
				// 用户指定要保存的文件
				int ret = chooser.showSaveDialog ( this );
				if ( ret == JFileChooser.APPROVE_OPTION )
				{

					byte[] bytK1 = getKeyByStr ( sKey.substring ( 0, 16 ) );
					byte[] bytK2 = getKeyByStr ( sKey.substring ( 16, 32 ) );
					byte[] bytK3 = getKeyByStr ( sKey.substring ( 32, 48 ) );

					FileInputStream fis = new FileInputStream ( fileIn );
					byte[] bytIn = new byte[ ( int ) fileIn.length() ];
					for ( int i = 0; i < fileIn.length(); i++ )
					{
						bytIn[i] = ( byte ) fis.read();
					}
					// 解密
					byte[] bytOut = decryptByDES (
					                    decryptByDES ( decryptByDES ( bytIn, bytK3 ), bytK2 ),
					                    bytK1 );
					File fileOut = chooser.getSelectedFile();
					fileOut.createNewFile();
					FileOutputStream fos = new FileOutputStream ( fileOut );
					for ( int i = 0; i < bytOut.length; i++ )
					{
						fos.write ( ( int ) bytOut[i] );
					}
					fos.close();
					JOptionPane.showMessageDialog ( this, "解密成功！", "提示",
					                                JOptionPane.OK_OPTION );
				}
			}
			else
				JOptionPane.showMessageDialog ( this, "密码长度必须等于48！", "错误信息",
				                                JOptionPane.ERROR_MESSAGE );
		}
		catch ( Exception e )
		{
			JOptionPane.showMessageDialog ( this, "解密失败，请核对密码！", "提示",
			                                JOptionPane.OK_OPTION );
		}
	}

	/**
	 * 用DES方法加密输入的字节 bytKey需为8字节长，是加密的密码
	 */
	private byte[] encryptByDES ( byte[] bytP, byte[] bytKey ) throws Exception
	{
		DESKeySpec desKS = new DESKeySpec ( bytKey );
		SecretKeyFactory skf = SecretKeyFactory.getInstance ( "DES" );
		SecretKey sk = skf.generateSecret ( desKS );
		Cipher cip = Cipher.getInstance ( "DES" );
		cip.init ( Cipher.ENCRYPT_MODE, sk );
		return cip.doFinal ( bytP );
	}

	/**
	 * 用DES方法解密输入的字节 bytKey需为8字节长，是解密的密码
	 */
	private byte[] decryptByDES ( byte[] bytE, byte[] bytKey ) throws Exception
	{
		DESKeySpec desKS = new DESKeySpec ( bytKey );
		SecretKeyFactory skf = SecretKeyFactory.getInstance ( "DES" );
		SecretKey sk = skf.generateSecret ( desKS );
		Cipher cip = Cipher.getInstance ( "DES" );
		cip.init ( Cipher.DECRYPT_MODE, sk );
		return cip.doFinal ( bytE );
	}

	/**
	 * 输入密码的字符形式，返回字节数组形式。 如输入字符串：AD67EA2F3BE6E5AD 返回字节数组：{
	 * 173,103,234,47,59,230,229,173 }
	 */
	private byte[] getKeyByStr ( String str )
	{
		byte[] bRet = new byte[str.length() / 2];
		for ( int i = 0; i < str.length() / 2; i++ )
		{
			Integer itg = new Integer ( 16 * getChrInt ( str.charAt ( 2 * i ) )
			                            + getChrInt ( str.charAt ( 2 * i + 1 ) ) );
			bRet[i] = itg.byteValue();
		}
		return bRet;
	}

	/**
	 * 计算一个16进制字符的10进制值 输入：0-F
	 */
	private int getChrInt ( char chr )
	{
		int iRet = 0;
		if ( chr == "0".charAt ( 0 ) )
			iRet = 0;
		if ( chr == "1".charAt ( 0 ) )
			iRet = 1;
		if ( chr == "2".charAt ( 0 ) )
			iRet = 2;
		if ( chr == "3".charAt ( 0 ) )
			iRet = 3;
		if ( chr == "4".charAt ( 0 ) )
			iRet = 4;
		if ( chr == "5".charAt ( 0 ) )
			iRet = 5;
		if ( chr == "6".charAt ( 0 ) )
			iRet = 6;
		if ( chr == "7".charAt ( 0 ) )
			iRet = 7;
		if ( chr == "8".charAt ( 0 ) )
			iRet = 8;
		if ( chr == "9".charAt ( 0 ) )
			iRet = 9;
		if ( chr == "A".charAt ( 0 ) )
			iRet = 10;
		if ( chr == "B".charAt ( 0 ) )
			iRet = 11;
		if ( chr == "C".charAt ( 0 ) )
			iRet = 12;
		if ( chr == "D".charAt ( 0 ) )
			iRet = 13;
		if ( chr == "E".charAt ( 0 ) )
			iRet = 14;
		if ( chr == "F".charAt ( 0 ) )
			iRet = 15;
		return iRet;
	}
}

/**
 * 文件选择组件。
 */
class FilePanel extends JPanel
{
	FilePanel ( String str )
	{
		JLabel label = new JLabel ( str );
		JTextField fileText = new JTextField ( 35 );
		JButton chooseButton = new JButton ( "浏览..." );
		this.add ( label );
		this.add ( fileText );
		this.add ( chooseButton );
		clickAction ca = new clickAction ( this );
		chooseButton.addActionListener ( ca );

	}

	public String getFileName()
	{
		JTextField jtf = ( JTextField ) this.getComponent ( 1 );
		return jtf.getText();
	}

	private class clickAction implements ActionListener
	{
		clickAction ( Component c )
		{
			cmpt = c;
		}

		public void actionPerformed ( ActionEvent event )
		{
			JFileChooser chooser = new JFileChooser();
			chooser.setCurrentDirectory ( new File ( "." ) );
			int ret = chooser.showOpenDialog ( cmpt );
			if ( ret == JFileChooser.APPROVE_OPTION )
			{
				JPanel jp = ( JPanel ) cmpt;
				JTextField jtf = ( JTextField ) jp.getComponent ( 1 );
				jtf.setText ( chooser.getSelectedFile().getPath() );
			}
		}

		private Component cmpt;
	}
}

/**
 * 密码生成组件。
 */
class KeyPanel extends JPanel
{
	KeyPanel ( String str )
	{
		JLabel label = new JLabel ( str );
		JTextField fileText = new JTextField ( 35 );
		JButton chooseButton = new JButton ( "随机产生" );
		this.add ( label );
		this.add ( fileText );
		this.add ( chooseButton );
		clickAction ca = new clickAction ( this );
		chooseButton.addActionListener ( ca );

	}

	// 返回生成的密码（48个字符长度）
	public String getKey()
	{
		JTextField jtf = ( JTextField ) this.getComponent ( 1 );
		return jtf.getText();
	}

	private class clickAction implements ActionListener
	{
		clickAction ( Component c )
		{
			cmpt = c;
		}

		public void actionPerformed ( ActionEvent event )
		{
			try
			{
				KeyGenerator kg = KeyGenerator.getInstance ( "DES" );
				kg.init ( 56 );
				Key ke = kg.generateKey();
				byte[] bytK1 = ke.getEncoded();
				ke = kg.generateKey();
				byte[] bytK2 = ke.getEncoded();
				ke = kg.generateKey();
				byte[] bytK3 = ke.getEncoded();

				JPanel jp = ( JPanel ) cmpt;
				JTextField jtf = ( JTextField ) jp.getComponent ( 1 );
				jtf.setText ( getByteStr ( bytK1 ) + getByteStr ( bytK2 )
				              + getByteStr ( bytK3 ) );
			}
			catch ( Exception e )
			{
				e.printStackTrace();
			}
		}

		private String getByteStr ( byte[] byt )
		{
			String strRet = "";
			for ( int i = 0; i < byt.length; i++ )
			{
				// System.out.println(byt[i]);
				strRet += getHexValue ( ( byt[i] & 240 ) / 16 );
				strRet += getHexValue ( byt[i] & 15 );
			}
			return strRet;
		}

		private String getHexValue ( int s )
		{
			String sRet = null;
			switch ( s )
			{
			case 0:
				sRet = "0";
				break;
			case 1:
				sRet = "1";
				break;
			case 2:
				sRet = "2";
				break;
			case 3:
				sRet = "3";
				break;
			case 4:
				sRet = "4";
				break;
			case 5:
				sRet = "5";
				break;
			case 6:
				sRet = "6";
				break;
			case 7:
				sRet = "7";
				break;
			case 8:
				sRet = "8";
				break;
			case 9:
				sRet = "9";
				break;
			case 10:
				sRet = "A";
				break;
			case 11:
				sRet = "B";
				break;
			case 12:
				sRet = "C";
				break;
			case 13:
				sRet = "D";
				break;
			case 14:
				sRet = "E";
				break;
			case 15:
				sRet = "F";
			}
			return sRet;
		}

		private Component cmpt;
	}
}