用java寫個(gè)文件加密的代碼該怎么寫

import java.awt.*;

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import java.awt.event.*;

import javax.swing.*;

import java.io.*;

import java.security.*;

import javax.crypto.*;

import javax.crypto.spec.*;

/**

文件名：FileEncrypter.java

JDK：1.40以上

說明：文件加密

加密方法：三重DES加密

加密過程：對選中的文件加密后在同文件夾下生成一個(gè)增加了".tdes"

擴(kuò)展名的加密文件

解密過程：對選中的加密文件（必須有".tdes"擴(kuò)展名）進(jìn)行解密

*/

public class FileEncrypter extends JFrame{

public static final int WIDTH = 550;

public static final int HEIGHT = 200;

public static void main(String args[]) {

FileEncrypter fe = new FileEncrypter();

fe.show();

}

FileEncrypter(){

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("文件選擇");

c.add(fp);

final KeyPanel pp = new KeyPanel("密碼");

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,"請選擇文件！","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,"請選擇文件！","提示",JOptionPane.OK_OPTION);

}

});

}

/**

加密函數(shù)

輸入：

要加密的文件，密碼（由0-F組成，共48個(gè)字符，表示3個(gè)8位的密碼）如：

AD67EA2F3BE6E5ADD368DFE03120B5DF92A8FD8FEC2F0746

其中：

AD67EA2F3BE6E5AD DES密碼一

D368DFE03120B5DF DES密碼二

92A8FD8FEC2F0746 DES密碼三

輸出：

對輸入的文件加密后，保存到同一文件夾下增加了".tdes"擴(kuò)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;iFILEIN.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;iBYTOUT.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,"密碼長度必須等于48！","錯誤信息",JOptionPane.ERROR_MESSAGE);

}catch(Exception e){

e.printStackTrace();

}

}

/**

解密函數(shù)

輸入：

要解密的文件，密碼（由0-F組成，共48個(gè)字符，表示3個(gè)8位的密碼）如：

AD67EA2F3BE6E5ADD368DFE03120B5DF92A8FD8FEC2F0746

其中：

AD67EA2F3BE6E5AD DES密碼一

D368DFE03120B5DF DES密碼二

92A8FD8FEC2F0746 DES密碼三

輸出：

對輸入的文件解密后，保存到用戶指定的文件中。

*/

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));

//用戶指定要保存的文件

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;iFILEIN.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;iBYTOUT.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,"密碼長度必須等于48！","錯誤信息",JOptionPane.ERROR_MESSAGE);

}catch(Exception e){

JOptionPane.showMessageDialog(

this,"解密失敗，請核對密碼！","提示",JOptionPane.OK_OPTION);

}

}

/**

用DES方法加密輸入的字節(jié)

bytKey需為8字節(jié)長，是加密的密碼

*/

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方法解密輸入的字節(jié)

bytKey需為8字節(jié)長，是解密的密碼

*/

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);

}

/**

輸入密碼的字符形式，返回字節(jié)數(shù)組形式。

如輸入字符串：AD67EA2F3BE6E5AD

返回字節(jié)數(shù)組：{173,103,234,47,59,230,229,173}

*/

private byte[] getKeyByStr(String str){

byte[] bRet = new byte[str.length()/2];

for(int i=0;iSTR.LENGTH()

Integer itg =

new Integer(16*getChrInt(str.charAt(2*i)) + getChrInt(str.charAt(2*i+1)));

bRet[i] = itg.byteValue();

}

return bRet;

}

/**

計(jì)算一個(gè)16進(jìn)制字符的10進(jìn)制值

輸入：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;

}

}

/**

文件選擇組件。

*/

class FilePanel extends JPanel{

FilePanel(String str){

JLabel label = new JLabel(str);

JTextField fileText = new JTextField(35);

JButton chooseButton = new JButton("瀏覽...");

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;

}

}

/**

密碼生成組件。

*/

class KeyPanel extends JPanel{

KeyPanel(String str){

JLabel label = new JLabel(str);

JTextField fileText = new JTextField(35);

JButton chooseButton = new JButton("隨機(jī)產(chǎn)生");

this.add(label);

this.add(fileText);

this.add(chooseButton);

clickAction ca = new clickAction(this);

chooseButton.addActionListener(ca);

}

//返回生成的密碼（48個(gè)字符長度）

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;iBYT.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;

}

}

JAVA代碼中怎么限制輸入的字符長度

使用DocumentFilter

import java.awt.EventQueue;

import java.awt.GridBagLayout;

import java.awt.Toolkit;

import javax.print.attribute.AttributeSet;

import javax.swing.JFrame;

import javax.swing.JTextField;

import javax.swing.UIManager;

import javax.swing.UnsupportedLookAndFeelException;

import javax.swing.text.AbstractDocument;

import javax.swing.text.BadLocationException;

import javax.swing.text.DocumentFilter;

import javax.swing.text.DocumentFilter.FilterBypass;

public class FilterTest {

public static void main(String[] args) {

new FilterTest();

}

public FilterTest() {

EventQueue.invokeLater(new Runnable() {

@Override

public void run() {

try {

UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {

}

JTextField field = new JTextField(10);

((AbstractDocument)field.getDocument()).setDocumentFilter(new SizeFilter(5));

JFrame frame = new JFrame("Testing");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setLayout(new GridBagLayout());

frame.add(field);

frame.pack();

frame.setLocationRelativeTo(null);

frame.setVisible(true);

}

});

}

public class SizeFilter extends DocumentFilter {

private int maxCharacters;

public SizeFilter(int maxChars) {

maxCharacters = maxChars;

}

public void insertString(FilterBypass fb, int offs, String str, AttributeSet a)

throws BadLocationException {

if ((fb.getDocument().getLength() + str.length()) = maxCharacters) {

super.insertString(fb, offs, str, a);

} else {

Toolkit.getDefaultToolkit().beep();

}

}

public void replace(FilterBypass fb, int offs, int length, String str, AttributeSet a)

throws BadLocationException {

if ((fb.getDocument().getLength() + str.length()

- length) = maxCharacters) {

super.replace(fb, offs, length, str, a);

} else {

Toolkit.getDefaultToolkit().beep();

}

}

}

}

java編程如何實(shí)現(xiàn)限制賬號密碼長度和包含數(shù)字、字母？

正則表達(dá)式，是最好的方式。

下面這個(gè)正是判斷必須同時(shí)包含數(shù)字和字母的。長度單獨(dú)檢測。

public static void main(String[] argv) {

String reg = "^(\\d+[A-Za-z]+[A-Za-z0-9]*)|([A-Za-z]+\\d+[A-Za-z0-9]*)$";

String name1 = "aaaaaaaaaaa";

String name2 = "123566778";

String name3 = "123123dfgdg";

String name4 = "sdf1rgdd2398gfdhgdwg32452342";

System.out.println(name1.matches(reg));

System.out.println(name2.matches(reg));

System.out.println(name3.matches(reg));

System.out.println(name4.matches(reg));

}

當(dāng)前題目：java限制密碼長度代碼 java密碼加密代碼
標(biāo)題鏈接：http://vcdvsql.cn/article18/hejdgp.html

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