如果文件已经下载，如何防止从URL下载文件

Question

我需要下载文件，并可能在断开连接后下载零件。尝试下载已经完全下载的文件时出现错误。尝试获取输入流时，我从服务器获取416错误代码。我通过添加条件downloadedFileSize

try {
                    File file = Path.of(downloadOutputFolder, fileName).toFile();
                    boolean append = false;
                    connection = (HttpURLConnection) url.openConnection();

                    if (file.exists()) {
                        connection.setRequestProperty("Range", String.format("bytes=%s-", file.length()));
                        append = true;
                    }
                    if (!file.exists() || file.exists() && file.length() < getFileSizeFromUrl(url)) {
                        try (InputStream downloadStream = connection.getInputStream();
                             FileOutputStream fileOutputStream = new FileOutputStream(file, append)) {
                            int byteRead;
                            byte[] buffer = new byte[BUFFER_SIZE];
                            while ((byteRead = downloadStream.read(buffer)) != -1) {
                                fileOutputStream.write(buffer, 0, byteRead);
                            }
                        }
                    }...

private int getFileSizeFromUrl(URL url) {
    HttpURLConnection connection = null;
    try {
        connection = (HttpURLConnection) url.openConnection();
        return connection.getContentLength();
    } catch (IOException e) {
        log.error("Error during open URL connection to {}", url, e);
    } finally {
        if (connection != null) {
            connection.disconnect();
        }
    }
    return -1;
}

是否可以使用url连接api处理这些情况？不是通过添加条件file.length()<getFileSizeFromUrl(url)。