有人用apache的ftp包進行訪問FTP么?

<%@ page contentType="text/html; charset=Big5" %>
<%@ page import ="org.apache.commons.net.ftp.*"%>
<%
FTPClient ftp = new FTPClient();
ftp.connect("172.24.14.229");//ip地址.
ftp.login("atonet","***");//用戶名密碼.
int aaa = ftp.getDefaultPort();
String bbb = ftp.getReplyString();
int remotePort = ftp.getRemotePort();
String[] name = ftp.listNames();
FTPFile[] listFile = ftp.listFiles();
我一執行到上面這步的時候就出錯,不知到怎么回事!