public static String MD5(String str)

        {

            MessageDigest md5 = null;

            try

            {

                md5 = MessageDigest.getInstance("MD5");

            }catch(Exception e)

            {

                e.printStackTrace();

                return "";

            }  

            char[] charArray = str.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();

        }