Apache Commons Net FTPClient and listFiles()

Question

Can anyone explain me what's wrong with the following code? I tried different hosts, FTPClientConfigs, it's properly accessible via firefox/filezilla... The problem is I always get empty filelist without any exceptions (files.length == 0). I use commons-net-2.1.jar installed with Maven.

    FTPClientConfig config = new FTPClientConfig(FTPClientConfig.SYST_L8);

    FTPClient client = new FTPClient();
    client.configure(config);

    client.connect("c64.rulez.org");
    client.login("anonymous", "anonymous");
    client.enterRemotePassiveMode();

    FTPFile[] files = client.listFiles();
    Assert.assertTrue(files.length > 0);

The problem is I always get empty filelist without any exceptions (files.length == 0). Question is updated. — Vladimir Mihailenco, Apr 26 '10 at 11:31
It works fine on my FTP server, except that I don't call client.configure(...) — Guillaume, Apr 26 '10 at 11:40
I tried also ftp.belnet.be / ftp.ccc.uba.ar and some private ftp servers and can't get it to work (even without client.configure)... I also tried to disable windows firewall and antivirus... Can you share some working ftp host? — Vladimir Mihailenco, Apr 26 '10 at 11:46
ftp4j basic example works properly, but I would like to know what's wrong with my commons-net code... — Vladimir Mihailenco, Apr 26 '10 at 14:13

score 101 · Accepted Answer · edited Sep 02 '14 at 21:45

101

Found it!

The thing is you want to enter passive mode after you connect, but before you log in. Your code returns nothing for me, but this works for me:

import org.apache.commons.net.ftp.FTPClient;
import java.io.IOException;
import org.apache.commons.net.ftp.FTPFile;

public class BasicFTP {

    public static void main(String[] args) throws IOException {
        FTPClient client = new FTPClient();
        client.connect("c64.rulez.org");
        client.enterLocalPassiveMode();
        client.login("anonymous", "");
        FTPFile[] files = client.listFiles("/pub");
        for (FTPFile file : files) {
            System.out.println(file.getName());
        }
    }
}

Gives me this output:

c128
c64
c64.hu
incoming
plus4

edited Sep 02 '14 at 21:45

JasonMArcher

14,195
22
56
52

answered Mar 03 '11 at 16:06

PapaFreud

3,636
4
34
45

1

(Regarding the BTW comment: `Assert.assertTrue` is from JUnit or TestNG; Java's assert would simply be `assert`. Anyway, I guess the point was just to illustrate desired outcome to readers of the question.) – Jonik Apr 15 '13 at 12:26
@Jonik Oh, that's right. I wasn't paying attention. I removed that bit. – PapaFreud Apr 19 '13 at 07:54
there are localpassive remotepassive, localactive, remoteactive i tried them one after another, and yeh localpassive worked – Junchen Liu Jul 11 '14 at 11:45
Thanks a ton my dear friend, i searched all the website but unable to find any solution to this issue. You code saved me! Just cool – Rajesh Kumar Yadav Jun 05 '19 at 18:49

suketup · Answer 2 · 2017-06-30T19:05:59.440

14

Only using enterLocalPassiveMode() did not work for me.

I used following code, which worked.

    ftpsClient.execPBSZ(0);
    ftpsClient.execPROT("P");
    ftpsClient.type(FTP.BINARY_FILE_TYPE);

Complete example is as below,

    FTPSClient ftpsClient = new FTPSClient();        

    ftpsClient.connect("Host", 21);

    ftpsClient.login("user", "pass");

    ftpsClient.enterLocalPassiveMode();

    ftpsClient.execPBSZ(0);
    ftpsClient.execPROT("P");
    ftpsClient.type(FTP.BINARY_FILE_TYPE);

    FTPFile[] files = ftpsClient.listFiles();

    for (FTPFile file : files) {
        System.out.println(file.getName());
    }

edited Jun 30 '17 at 19:05

answered Jun 01 '17 at 21:47

suketup

469
7
12

Cannot find methods: ftpClient.execPBSZ(0); ftpClient.execPROT("P") – Kamil Nękanowicz Jun 30 '17 at 05:57
Are you using FTPClient or FTPSClient? Those methods only exist in FTPSClient. – suketup Jun 30 '17 at 18:24

score 3 · Answer 3 · edited May 30 '14 at 19:03

3

usually the annonymous user doesn't need a password, try

client.login("anonymous", "");

edited May 30 '14 at 19:03

Paul Richter

10,908
10
52
85

answered Aug 13 '10 at 19:18

Gelvis

189
1
6

score 0 · Answer 4 · answered Dec 27 '20 at 05:10

For me it worked when I used ftpClient.enterLocalPassiveMode() just before calling ftpClient.listFiles(). Here is the full code:

                final List<String> files = new ArrayList<>();
                try {
                    ftpClient.enterLocalPassiveMode();
                    String[] f = null;
                    if (parentDir.isEmpty()) {
                        f = ftpClient.listNames();
                    }else{
                        f = ftpClient.listNames(parentDir);
                    }
                    for (String s :f ) {
                        files.add(s);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                    postError(e.getMessage()!= null?e.getMessage():e.toString());
                }

Apache Commons Net FTPClient and listFiles()

4 Answers4

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