python网络编程之文件下载实例分析

from ftplib import FTP
import sys
def ftpdownload(path,file):
  ftp = FTP()
  ftp.set_debuglevel(2)
  #打开调试级别2，显示详细信息
  ftp.connect('**IP**')
  #连接ftp服务器
  ftp.login(user,password)
  #输入用户名和密码
  print ftp.getwelcome()
  #显示ftp服务器的欢迎信息
  ftp.cwd(path)
  #选择操作目录
  bufsize = 1024
  #设置缓冲区大小
  file_handler = open(file,'wb').write
  #以写模式在本地打开文件
  strBuffer = 'RETR ' + file
  ftp.retrbinary(strBuffer,file_handler,bufsize)
  #接收服务器上文件并写入本地文件
  ftp.set_debuglevel(0) #关闭调试
  ftp.quit() #退出ftp服务器
if __name__ == '__main__':
  path1 = 'download/test/'
  file1 = 'test1.rar'
  if len(sys.argv) == 3:
    try:
      ftpdownload(sys.argv[1],sys.argv[2])
      #命令行输入文件在ftp上的路径和文件名，    
    except IOError:
      print "please input the correct path and filename"
  else:
    ftpdownload(path1,file1)

from ftplib import FTP
import sys,os
def ftpdownload(path,file):
  ftp = FTP()
  ftp.set_debuglevel(2)
  ftp.connect('**IP**')
  ftp.login(user,password)
  print ftp.getwelcome()
  ftp.cwd(path)
  bufsize = 1024
  file_handler = open(file,'rb')
  #读方式打开上传文件
  strBuffer = 'RETR ' + file
  ftp.storbinary(strBuffer,file_handler,bufsize)
  #上传文件
  ftp.set_debuglevel(0) 
  ftp.quit()
if __name__ == '__main__':
  path1 = 'download/test/'
  file1 = '4.jpg'
  if len(sys.argv) == 3:
    try:
      ftpdownload(sys.argv[1],sys.argv[2])      
    except IOError:
      print "please input the correct path and filename"
  else:
    ftpdownload(path1,file1)

import urllib
import sys
def download(url):
  starttime = datetime.datetime.now()
  print 'download start time is %s'% starttime
  urllib.urlretrieve(url,'test.exe')
  #开始下载，test.exe为下载后保存的文件名
  endtime = datetime.datetime.now()
  print 'download end time is %s'% endtime  
  print 'you download the file use time %s s' % (endtime - starttime).seconds
if __name__ == '__main__':
  if len(sys.argv) == 2:
    try:
      download(sys.argv[1])
    except IOError:
      print 'url not found'
  else:
    download('http://www.python.org/')