Java的MD5加密和解密

    import  java.security.*;  
    import  java.security.spec.*;  
      
    class  MD5_test {  
     public   final   static  String MD5(String s) {  
      char  hexDigits[] = {  \'0\' ,  \'1\' ,  \'2\' ,  \'3\' ,  \'4\' ,  \'5\' ,  \'6\' ,  \'7\' ,  \'8\' ,  \'9\' ,  
        \'a\' ,  \'b\' ,  \'c\' ,  \'d\' ,  \'e\' ,  \'f\'  };  
      try  {  
       byte [] strTemp = s.getBytes();  
       MessageDigest mdTemp = MessageDigest.getInstance("MD5" );  
       mdTemp.update(strTemp);  
       byte [] md = mdTemp.digest();  
       int  j = md.length;  
       char  str[] =  new   char [j *  2 ];  
       int  k =  0 ;  
       for  ( int  i =  0 ; i < j; i++) {  
        byte  byte0 = md[i];  
        str[k++] = hexDigits[byte0 >>> 4  &  0xf ];  
        str[k++] = hexDigits[byte0 & 0xf ];  
       }  
       return   new  String(str);  
      } catch  (Exception e) {  
       return   null ;  
      }  
     }  
      
     public   static   void  main(String[] args) {  
      // MD5_Test aa = new MD5_Test();   
      System.out.print(MD5_test.MD5("b" ));  
     }  
    }  

[java] view plain copy print?

    import java.security.*;  
    import java.security.spec.*;  
      
    class MD5_test {  
     public final static String MD5(String s) {  
      char hexDigits[] = { \'0\', \'1\', \'2\', \'3\', \'4\', \'5\', \'6\', \'7\', \'8\', \'9\',  
        \'a\', \'b\', \'c\', \'d\', \'e\', \'f\' };  
      try {  
       byte[] strTemp = s.getBytes();  
       MessageDigest mdTemp = MessageDigest.getInstance("MD5");  
       mdTemp.update(strTemp);  
       byte[] md = mdTemp.digest();  
       int j = md.length;  
       char str[] = new char[j * 2];  
       int k = 0;  
       for (int i = 0; i < j; i++) {  
        byte byte0 = md[i];  
        str[k++] = hexDigits[byte0 >>> 4 & 0xf];  
        str[k++] = hexDigits[byte0 & 0xf];  
       }  
       return new String(str);  
      } catch (Exception e) {  
       return null;  
      }  
     }  
      
     public static void main(String[] args) {  
      // MD5_Test aa = new MD5_Test();  
      System.out.print(MD5_test.MD5("b"));  
     }  
    }  

 
Java代码  收藏代码

    import  java.security.MessageDigest;  
      
      
    public   class  MD5andKL {  
     // MD5加码。32位   
     public   static  String MD5(String inStr) {  
      MessageDigest md5 = null ;  
      try  {  
       md5 = MessageDigest.getInstance("MD5" );  
      } catch  (Exception e) {  
       System.out.println(e.toString());  
       e.printStackTrace();  
       return   "" ;  
      }  
      char [] charArray = inStr.toCharArray();  
      byte [] byteArray =  new   byte [charArray.length];  
      
      for  ( int  i =  0 ; i < charArray.length; i++)  
       byteArray[i] = (byte ) charArray[i];  
      
      byte [] md5Bytes = md5.digest(byteArray);  
      
      StringBuffer hexValue = new  StringBuffer();  
      
      for  ( int  i =  0 ; i < md5Bytes.length; i++) {  
       int  val = (( int ) md5Bytes[i]) &  0xff ;  
       if  (val <  16 )  
        hexValue.append("0" );  
       hexValue.append(Integer.toHexString(val));  
      }  
      
      return  hexValue.toString();  
     }  
      
     // 可逆的加密算法   
     public   static  String KL(String inStr) {  
      // String s = new String(inStr);   
      char [] a = inStr.toCharArray();  
      for  ( int  i =  0 ; i < a.length; i++) {  
       a[i] = (char ) (a[i] ^  \'t\' );  
      }  
      String s = new  String(a);  
      return  s;  
     }  
      
     // 加密后解密   
     public   static  String JM(String inStr) {  
      char [] a = inStr.toCharArray();  
      for  ( int  i =  0 ; i < a.length; i++) {  
       a[i] = (char ) (a[i] ^  \'t\' );  
      }  
      String k = new  String(a);  
      return  k;  
     }  
       
     // 测试主函数   
     public   static   void  main(String args[]) {  
      String s = new  String( "a" );  
      System.out.println("原始："  + s);  
      System.out.println("MD5后："  + MD5(s));  
      System.out.println("MD5后再加密："  + KL(MD5(s)));  
      System.out.println("解密为MD5后的："  + JM(KL(MD5(s))));  
     }  
    }  

[java] view plain copy print?

    import java.security.MessageDigest;  
      
      
    public class MD5andKL {  
     // MD5加码。32位  
     public static String MD5(String inStr) {  
      MessageDigest md5 = null;  
      try {  
       md5 = MessageDigest.getInstance("MD5");  
      } catch (Exception e) {  
       System.out.println(e.toString());  
       e.printStackTrace();  
       return "";  
      }  
      char[] charArray = inStr.toCharArray();  
      byte[] byteArray = new byte[charArray.length];  
      
      for (int i = 0; i < charArray.length; i++)  
       byteArray[i] = (byte) charArray[i];  
      
      byte[] md5Bytes = md5.digest(byteArray);  
      
      StringBuffer hexValue = new StringBuffer();  
      
      for (int i = 0; i < md5Bytes.length; i++) {  
       int val = ((int) md5Bytes[i]) & 0xff;  
       if (val < 16)  
        hexValue.append("0");  
       hexValue.append(Integer.toHexString(val));  
      }  
      
      return hexValue.toString();  
     }  
      
     // 可逆的加密算法  
     public static String KL(String inStr) {  
      // String s = new String(inStr);  
      char[] a = inStr.toCharArray();  
      for (int i = 0; i < a.length; i++) {  
       a[i] = (char) (a[i] ^ \'t\');  
      }  
      String s = new String(a);  
      return s;  
     }  
      
     // 加密后解密  
     public static String JM(String inStr) {  
      char[] a = inStr.toCharArray();  
      for (int i = 0; i < a.length; i++) {  
       a[i] = (char) (a[i] ^ \'t\');  
      }  
      String k = new String(a);  
      return k;  
     }  
       
     // 测试主函数  
     public static void main(String args[]) {  
      String s = new String("a");  
      System.out.println("原始：" + s);  
      System.out.println("MD5后：" + MD5(s));  
      System.out.println("MD5后再加密：" + KL(MD5(s)));  
      System.out.println("解密为MD5后的：" + JM(KL(MD5(s))));  
     }  
    }