java - 我正在尝试下载我的网络服务器上的 pdf 文件，但是下载时我的文件已损坏

Question

private Boolean downloadAndSaveFile(String server, int portNumber,String user, String password) throws IOException {

    FTPClient ftp = null;
    // path of a file which is on a web server
    String remoteFile1 = "/public_html/1/c language/Unit_1_HTML_and_Forms.pdf";
    // Path of my device
    File downloadFile1 = new File("/storage/emulated/0/a/new.pdf");
    try {
        ftp = new FTPClient();
        ftp.connect(server, portNumber);
        ftp.login(user, password);
        ftp.setFileType(FTP.BINARY_FILE_TYPE);
        ftp.enterLocalPassiveMode();
        System.out.println("Reached passive");
        OutputStream outputStream1 = new BufferedOutputStream(new FileOutputStream(downloadFile1));
        System.out.println("Stream Created");
        boolean success = ftp.retrieveFile(remoteFile1, outputStream1);
        System.out.println(success);
        return true;
    } catch(Exception e) {
        System.out.println(e);
    } finally {
        if (ftp != null) {
            ftp.logout();
            ftp.disconnect();
        }
    }
    return true;
}

Answer 1

我认为 retriveFile(...) 不会关闭流。返回 true 后尝试刷新并关闭它(outputStream1)