* close a existing ftp connection
* @return FTPCLient
* @throws PageException
*/
private FTPClient actionClose() throws PageException {
FTPConnection conn = _createConnection();
FTPClient client = pool.remove(conn);
Struct cfftp = writeCfftp(client);
cfftp.setEL("succeeded",Caster.toBoolean(client!=null));
return client;