问题
I m using Apache FTPClient. I was a do a copy of file in a folder just like cp -p, but from Java. How can I do that using 'sendCommand' method or will it be possible any other way? The rename method moves the file but does not keep a backup copy.
回答1:
There's no standard way to duplicate a remote file over FTP protocol. Some FTP servers support proprietary or non-standard extensions for this though.
So if your are lucky that your server is ProFTPD with mod_copy module, you can use FTP.sendCommand to issue these two commands:
CPFR sourcepath
CPTO targetpath
The second possibility is that your server allows you to execute arbitrary shell commands. This is not common either. If your server supports this you can use SITE EXEC command:
SITE EXEC cp -p sourcepath targetpath
Another workaround is to open a second connection to the FTP server and make the server upload the file to itself by piping a passive mode data connection to an active mode data connection. Implementation of this solution in PHP is shown in FTP copy a file to another place in same FTP.
If neither of this works, all you can do is to download the file to a local temporary location and re-upload it back to the target location.
See also:
- FTP copy a file to another place in same FTP.
- How to copy a file on the ftp server to a directory on the same server in java?
来源：https://stackoverflow.com/questions/33490147/duplicate-remote-file-over-ftp-protocol-in-java-cp-p-to-linux-using-sendcomman