URLConnection FTP list files

Question

URL url =  new URL(\"ftp://user:pass@ftp.example.com/thefolder/\");
URLConnection connection = url.openConnection();
...
// List files in folder...

Answer 1

The Java SE URLConnection is insuitable for the job of retrieving a list of files from a FTP host. As to FTP, it basically only supports the FTP get or put commands (retrieve or upload file). It does not support the FTP ls command (list files) which you're basically looking for, let alone many others.

You need to look for 3rd party libraries supporting the FTP ls command (and many more). A commonly used one is the Apache Commons Net FtpClient. In its javadoc is demonstrated how to issue a ls:

FTPClient f = new FTPClient();
f.connect(server);
f.login(username, password);
FTPFile[] files = f.listFiles(directory);