import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

/**

 * MD5

 */

public class MD5Util {

    public static char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};

    public static String md5(String s) {

        try {

            MessageDigest messagedigest = MessageDigest.getInstance("MD5");

            messagedigest.update(s.getBytes());

            byte[] digestByte = messagedigest.digest();

            return bufferToHex(digestByte, 0, digestByte.length);

        } catch (NoSuchAlgorithmException e) {

            e.printStackTrace();

            return null;

        }

    }

    private static String bufferToHex(byte bytes[], int m, int n) {

        StringBuffer stringbuffer = new StringBuffer(2 * n);

        int k = m + n;

        for ( int  l = m; l < k; l++) {

            appendHexPair(bytes[l], stringbuffer);

        }

        return stringbuffer.toString();

    }

    private static void appendHexPair(byte bt, StringBuffer stringbuffer) {

        char c0 = hexDigits[(bt &  0xf0 ) >>  4 ];

        char c1 = hexDigits[bt &  0xf ];

        stringbuffer.append(c0);

        stringbuffer.append(c1);

    }

}