MD5加密解密

package endecrypt;    import java.io.UnsupportedEncodingException;  import java.security.MessageDigest;  import java.security.NoSuchAlgorithmException;    /**  * 采用MD5加密解密  * @author tfq  * @datetime 2011-10-13  */  public class MD5Util {        /***      * MD5加码 生成32位md5码      */      public static String string2MD5(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();        }        /**      * 加密解密算法 执行一次加密，两次解密      */       public static String convertMD5(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;        }        // 测试主函数      public static void main(String args[]) {          String s = new String("tangfuqiang");          System.out.println("原始：" + s);          System.out.println("MD5后：" + string2MD5(s));          System.out.println("加密的：" + convertMD5(s));          System.out.println("解密的：" + convertMD5(convertMD5(s)));        }  }