1 直接下载

这种方法会把要下载的文件全部读进内存，只适用于小文件

import requests
url = 'http://hgdownload.cse.ucsc.edu/goldenPath/rn6/bigZips/rn6.fa.gz'
resp = requests.get(url)
with open('rn6.fa.gz', 'wb') as out:
    out.write(resp.content)

2 分块下载

设置stream=True，当执行iter_content时才开始下载指定大小，节省内存

import requests
url = 'http://hgdownload.cse.ucsc.edu/goldenPath/rn6/bigZips/rn6.fa.gz'
resp = requests.get(url, stream=True)
with open('rn6.fa.gz', 'wb') as out:
    for trunk in resp.iter_content(4096):  # 每次下载4096字节的数据
        out.write(content)