python从ftp上下载文件的方法：

首先导入ftp模块；

然后使用【chdir】命令切换工作路径；

再使用“self.ftp.nlst()”命令获取目录下的文件；

最后使用“self.ftp.retrbinary()”命令下载ftp文件即可。

#!/usr/bin/python

# coding=utf-8

import os

from ftplib import FTP # 引入ftp模块

class MyFtp:

ftp = FTP()

def __init__(self,host,port=21):

self.ftp.connect(host,port)

def login(self,username,pwd):

self.ftp.set_debuglevel(2) # 打开调试级别2，显示详细信息

self.ftp.login(username,pwd)

p

rint(self.ftp.welcome)

def downloadFile(self,localpath,remotepath,filename):

os.chdir(localpath) # 切换工作路径到下载目录

self.ftp.cwd( remotepath) # 要登录的ftp目录

self.ftp.nlst() # 获取目录下的文件

file_handle = open(filename,"wb").write # 以写模式在本地打开文件

self.ftp.retrbinary('RETR %s' % os.path.basename(filename),file_handle,blocksize=1024) # 下载ftp文件

# ftp.delete(filename) # 删除ftp服务器上的文件

def close(self):

self.ftp.set_debuglevel(0) # 关闭调试

self.ftp.quit()if __name__ == '__main__':

ftp = MyFtp('host')

ftp.login('username','pwd')

ftp.downloadFile('E:\\RED\\workspace\\appAuto\\apk\\Android10','/mobile/Android/release10/','xxx.apk')

ftp.close()

实例扩展：

#coding=utf-8

'''

ftp自动下载、自动上传脚本，可以递归目录操作

'''

from ftplib import FTP

import os,sys,string,datetime,time

import socket

class MYFTP:

def __init__(self, hostaddr, username, password, remotedir, port=21):

self.hostaddr = hostaddr

self.username = username

self.password = password

self.remotedir = remotedir

self.port = port

self.ftp = FTP()

self.file_list = []

# self.ftp.set_debuglevel(2)

def __del__(self):

self.ftp.close()

# self.ftp.set_debuglevel(0)

def login(self):

ftp = self.ftp

try:

timeout = 300

socket.setdefaulttimeout(timeout)

ftp.set_pasv(True)

print u'开始连接到 %s' %(self.hostaddr)

ftp.connect(self.hostaddr, self.port)

print u'成功连接到 %s' %(self.hostaddr)

print u'开始登录到 %s' %(self.hostaddr)

ftp.login(self.username, self.password)

print u'成功登录到 %s' %(self.hostaddr)

debug_print(ftp.getwelcome())

except Exception:

print u'连接或登录失败'

try:

ftp.cwd(self.remotedir)

except(Exception):

print u'切换目录失败'

def is_same_size(self, localfile, remotefile):

try:

remotefile_size = self.ftp.size(remotefile)

except:

remotefile_size = -1

try:

localfile_size = os.path.getsize(localfile)

except:

localfile_size = -1

debug_print('localfile_size:%d remotefile_size:%d' %(localfile_size, remotefile_size),)

if remotefile_size == localfile_size:

return 1

else:

return 0

def download_file(self, localfile, remotefile):

if self.is_same_size(localfile, remotefile):

debug_print(u'%s 文件大小相同，无需下载' %localfile)

return

else:

debug_print(u'>>>>>>>>>>>>下载文件 %s ... ...' %localfile)

#return

file_handler = open(localfile, 'wb')

self.ftp.retrbinary(u'RETR %s'%(remotefile), file_handler.write)

file_handler.close()

def download_files(self, localdir='./', remotedir='./'):

try:

self.ftp.cwd(remotedir)

except:

debug_print(u'目录%s不存在，继续...' %remotedir)

return

if not os.path.isdir(localdir):

os.makedirs(localdir)

debug_print(u'切换至目录 %s' %self.ftp.pwd())

self.file_list = []

self.ftp.dir(self.get_file_list)

remotenames = self.file_list

#print(remotenames)

#return

for item in remotenames:

filetype = item[0]

filename = item[1]

local = os.path.join(localdir, filename)

if filetype == 'd':

self.download_files(local, filename)

elif filetype == '-':

self.download_file(local, filename)

self.ftp.cwd('..')

debug_print(u'返回上层目录 %s' %self.ftp.pwd())

def upload_file(self, localfile, remotefile):

if not os.path.isfile(localfile):

return

if self.is_same_size(localfile, remotefile):

debug_print(u'跳过[相等]: %s' %localfile)

return

file_handler = open(localfile, 'rb')

self.ftp.storbinary('STOR %s' %remotefile, file_handler)

file_handler.close()

debug_print(u'已传送: %s' %localfile)

def upload_files(self, localdir='./', remotedir = './'):

if not os.path.isdir(localdir):

return

localnames = os.listdir(localdir)

self.ftp.cwd(remotedir)

for item in localnames:

src = os.path.join(localdir, item)

if os.path.isdir(src):

try:

self.ftp.mkd(item)

except:

debug_print(u'目录已存在 %s' %item)

self.upload_files(src, item)

else:

self.upload_file(src, item)

self.ftp.cwd('..')

def get_file_list(self, line):

ret_arr = []

file_arr = self.get_filename(line)

if file_arr[1] not in ['.', '..']:

self.file_list.append(file_arr)

def get_filename(self, line):

pos = line.rfind(':')

while(line[pos] != ' '):

pos += 1

while(line[pos] == ' '):

pos += 1

file_arr = [line[0], line[pos:]]

return file_arr

def debug_print(s):

print s

if __name__ == '__main__':

timenow = time.localtime()

datenow = time.strftime('%Y-%m-%d', timenow)

# 配置如下变量

hostaddr = '211.15.113.45' # ftp地址

username = 'UserName' # 用户名

password = '123456' # 密码

port = 21 # 端口号

rootdir_local = 'E:/mypiv' # 本地目录

rootdir_remote = '/PIV' # 远程目录

f = MYFTP(hostaddr, username, password, rootdir_remote, port)

f.login()

f.download_files(rootdir_local, rootdir_remote)

timenow = time.localtime()

datenow = time.strftime('%Y-%m-%d', timenow)

logstr = u"%s 成功执行了备份n" %datenow

debug_print(logstr)