python打开url并按指定块读取网页内容的方法

import urllib
pagehandler = urllib.urlopen("http://www.baidu.com")
outputfile = open("index.html", "wb")
while 1:
 data = pagehandler.read(512)
 if not data:
  break
 outputfile.write(data)
outputfile.close()
pagehandler.close()