java MD5

public final static String MD5(String s) {
		byte[] btInput = s.getBytes();
		MessageDigest mdInst = null;
		try {
			mdInst = MessageDigest.getInstance("MD5");
		} catch (NoSuchAlgorithmException e) {
			System.out.println("NoSuchAlgorithmException:md5");
			e.printStackTrace();
			return null;
		}
		mdInst.update(btInput);
		byte[] md = mdInst.digest();
		StringBuffer sb = new StringBuffer();
		for (byte i = 0; i < md.length; i++) {
			int val = ((int) md[i]) & 0xff;
			if (val < 16) sb.append("0");
			sb.append(Integer.toHexString(val));
		}
		return sb.toString();
	}