import org.apache.commons.net.ftp.FTPFile;
import java.util.Calendar;
.....

FTPClient ftp = new FTPClient();
....
FTPFile[] fs = ftp.listFiles();

for (int i = 0; i < fs.length; i++) {
    FTPFile ff = fs[i];
    String fileName=ff.getName();   //文件名
    Calendar c=ff.getTimestamp();   //修改时间
}