Issue with org.apache.commons.net.ftp.FTPClient listFiles()

Question

The listFiles() method of org.apache.commons.net.ftp.FTPClient works fine with Filezilla server on 127.0.0.1 but returns null on the r

Answer 1

Each FTP server has a different file list layout (yes, it's not part of the FTP standard, it's dumb), and so you have to use the correct FTPFileEntryParser, either by specifying it manually, or allowing CommonsFTP to auto-detect it.

Auto-detection usually works fine, but sometimes it doesn't, and you have to specify it explicitly, e.g.

FTPClientConfig conf = new FTPClientConfig(FTPClientConfig.SYST_UNIX);

FTPClient client = FTPClient();
client.configure(conf);

This explicitly sets the expected FTP server type to UNIX. Try the various types, see how it goes. I tried finding out myself, but ftp.belnet.be is refusing my connections :(

Answer 2

There was a parsing issue in earlier version of apache-Commons-net , the SYST command which returns the server type when returns null ( abruptly ) was not handled in parsingException . Try using the latest jar of apache-commons-net it may solve your problem.

Answer 3

Have you tried checking that you can list the files using normal FTP client? (For some reason, I cannot even connect to the FTP port of "belnet.be".)

EDIT

According to the javadoc for listFiles(), the parsing is done using the FTPFileEntryParser instance provided by the parser factory. You probably need to figure out which of the parsers matches the FTP server's LIST output and configure the factory accordingly.