java md5方法 for Android

 很简单的方法

    public static String md5(String string) {
        byte[] hash;
        try {
            hash = MessageDigest.getInstance("MD5").digest(string.getBytes("UTF-8"));
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException("Huh, MD5 should be supported?", e);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("Huh, UTF-8 should be supported?", e);
        }

        StringBuilder hex = new StringBuilder(hash.length * 2);
        for (byte b : hash) {
            if ((b & 0xFF) < 0x10) hex.append("0");
            hex.append(Integer.toHexString(b & 0xFF));
        }
        return hex.toString();
    }