对于Python2.7来说，内置的FTP_TLS类并不支持Implicit FTP Over TLS加密方式的FTP Server操作，为支持Implicit FTP Over TLS加密方式，必须重载内置的FTP_TLS类，具体代码如下：

import ftplibclass FTP_TLS(ftplib.FTP_TLS):    def __init__(self, host='', user='', passwd='', acct='', keyfile=None, certfile=None, timeout=180):        ftplib.FTP_TLS.__init__(self, host, user, passwd, acct, keyfile, certfile, timeout)    def connect(self, host='', port=0, timeout=-999):        if host != '':            self.host = host        if port > 0:            self.port = port        if timeout != -999:            self.timeout = timeout        try:            self.sock = socket.create_connection((self.host, self.port), self.timeout)            self.af = self.sock.family            self.sock = ssl.wrap_socket(self.sock, self.keyfile, self.certfile, ssl_version=ssl.PROTOCOL_TLSv1)            self.file = self.sock.makefile('rb')            self.welcome = self.getresp()        except Exception as e:            print e        return self.welcome    def download(self, remote_file_name, local_file_name):        with open(local_file_name, 'wb') as fp:            self.retrbinary('RETR %s' % remote_file_name, fp.write)

下载的示例代码如下所示：

host = 'XXX'    port = 2222    user = 'user'    password = 'pass'    local_dir = './data'    ftp = FTP_TLS()    ftp.connect(host, port)    LOG.debug('begin to login')    ftp.login(user, password)    LOG.debug('login succeed')    LOG.debug('welcome info = %s', ftp.getwelcome())    ftp.prot_p()    ftp.cwd('/crexbatch')    ftp.download('People.zip', 'People.zip')    ftp.retrlines('LIST')    fnames = ftp.nlst()    open('crexbatch.txt', 'wb').write('\r\n'.join(fnames))