import java.awt.*; 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 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 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;  } } 程序运行图：