java md5 compiling error

Question

Hi all, i just try to use MD5 library in java, but i got some errors,

when I try to compile it, I got this error :

digest(byte[],int,int) in java.security.MessageDigest cannot be applied to (byte[])

I try to compile it by wtk (j2me) What is the problem ?. thanks

here is the code

import java.io.FileInputStream;
import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class MD5 {
    public static String getMD5(String input) {
        try {
            MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] messageDigest = md.digest(input.getBytes());
            BigInteger number = new BigInteger(1, messageDigest);
            String hashtext = number.toString(16);
            // Now we need to zero pad it if you actually want the full 32 chars.
            while (hashtext.length() < 32) {
                hashtext = "0" + hashtext;
            }
            return hashtext;
        }
        catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        }
    }

    public static void main(String[] args) throws NoSuchAlgorithmException {
        System.out.println(getMD5("Javarmi.com"));
    }
}

Answer 1

Since you use WTK, perhaps you have this version of MessageDigest, it doesn't have digest(byte[]). So, you need to write something like this:

int MD_SIZE = 16;
byte[] messageDigest = new byte[MD_SIZE];
byte[] message = ...;
md.update(message, 0, message.length);
md.digest(messageDigest, 0, MD_SIZE);

Also note that you use String.getBytes(), so your digest depends on the system default encoding. You need to use String.getBytes(String encoding) in order to get portable results.