Java 远程url文件sha256加密

public static String getSHA256(String filePath) throws Exception {
        InputStream fis = null;
        URL url = new URL(filePath);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("GET");
        MessageDigest digest = MessageDigest.getInstance("SHA-256");
        byte[] buffer = new byte[1024];

        int responseCode = connection.getResponseCode();
        if (responseCode == HttpURLConnection.HTTP_OK) {
            fis = connection.getInputStream();
            int bytesRead;
            while ((bytesRead = fis.read(buffer)) != -1) {
                digest.update(buffer, 0, bytesRead);
            }
            fis.close();
        } else {
            throw new IOException("HTTP request failed with response code: " + responseCode);
        }

        byte[] sha256Bytes = digest.digest();

        StringBuilder sb = new StringBuilder();
        for (byte b : sha256Bytes) {
            sb.append(String.format("%02x", b));
        }

        String sha256 = sb.toString();
        return sha256;
    }