MD5数据加密

private static void Md5(String plainText ) {
          try {
               MessageDigest md = MessageDigest.getInstance("MD5");
               md.update(plainText.getBytes()); 
               byte b[] = md.digest();  

               int i;

               StringBuffer buf = new StringBuffer("");
               for (int offset = 0; offset < b.length; offset++) {
                     i = b[offset];
                     if(i<0) i+= 256;
                     if(i<16)
                     buf.append("0");
                     buf.append(Integer.toHexString(i));
                }

                          System.out.println("result: " + buf.toString());//32位的加密

                           System.out.println("result: " + buf.toString().substring(8,24));//16位的加密

                } catch (NoSuchAlgorithmException e) { 
                             e.printStackTrace();
                 }
}

                    Md5("12312312312312"); 结果: 
                    result: ba56bab91016bcb37878e06c16e9e68f