Android FTP 错误 - 425 无法打开数据连接

Question

我正在使用它来上传一些文件。如果我在本地连接中它会工作，但如果我使用外部连接，我会收到此消息:425 无法打开数据连接。 来自 ftp 服务器。

我使用 org.apache.commons.net.ftp.FTPClient 和 org.apache.commons.net.ftp.FTPFile 库。

public static String gravaImagem(String photoFile) {
    FTPClient mFtp = new FTPClient();
    try {
    mFtp.connect(FTPHOST, PORTA);
    mFtp.login(USUARIO, SENHA);
    mFtp.setFileTransferMode(FTPClient.BINARY_FILE_TYPE);
    mFtp.setFileType(FTPClient.BINARY_FILE_TYPE);
    String origem = Environment.getExternalStorageDirectory().getPath()+File.separator+"Pictures"+File.separator+"ImageSec"+File.separator+photoFile;
    FileInputStream fis = new FileInputStream(origem);
    mFtp.storeFile(photoFile, fis);
    mFtp.logout();
    mFtp.disconnect();
    } catch (SocketException e) {
    e.printStackTrace();
    return "Fail. (ERR#CON3)";
    } catch (IOException e) {
    e.printStackTrace();
    return "Fail. (ERR#CON4)";
    }
    return "Imagem enviada ao servidor.";
}

调试显示没有异常。

Answer 1

来自互联网:

First - the most common solution: change the active/passive mode settings. But that might not work, and if it does its only a band-aid covering up the real problem.

As I've mentioned in the past, one of the most common reasons that this error occurs is a misconfiguration of the FTP server software itself, related to SSL connections and firewalls, in which the connection tries to establish itself on a bogus ip address. Read more about FTP SSL through a NAT firewall here, some potential solutions are included.

There are other less likely causes, such as:

• The server is configured to always use the same port for passive mode connections, or the client is configured to always use the same port for active mode connections, although in this case usually the software in question should raise a different error first, but I've seen this happen.
• In passive mode, the firewall in front of the FTP server doesn't have the correct ports open. So the server tells the client to connect to ipaddress 1.2.3.4 on port x, but the firewall doesn't allow incoming connections on port x. Most firewalls are smart enough to open up the port when it sees the PASV response. Vice versa for active mode and the firewall in front of the FTP client.

来 self : 我在 andoird 上使用过这个库，它运行良好，所以请参阅我的复制/粘贴部分。