java16进制转字符串方法

public  String printHexString(byte[] b) {
        String res = "";
        for (int i = 0; i < b.length; i++) {
            String hex = Integer.toHexString(b[i] & 0xFF);
            if (hex.length() == 1) {
                hex = '0' + hex;
            }
            res += hex;
        }
        return res;
    }