Python下载大文件

def download_file(url):
local_filename = url.split('/')[-1]
# NOTE the stream=True parameter
r = requests.get(url, stream=True)
with open(local_filename, 'wb') as f:
    for chunk in r.iter_content(chunk_size=1024): 
        if chunk: # filter out keep-alive new chunks
            f.write(chunk)
            f.flush()
return local_filename

file = urllib2.urlopen('url')
with open('filename','w') as f:
    while True:
        tmp = file.read(1024)
        if not tmp:
            break 
        f.write(tmp)