多线程

from threading import Thread
from urllib import request

def downloader(url):
file_name = url.split(’/’)[-1]

response = request.urlopen(url)
content = response.read()

with open(file_name,'wb') as fp:
    fp.write(content)
print('子线程任务完成！')

if name == ‘main’:
#主进程下面有一个主线程

url_list = [
    'http://www.langlang2017.com/img/logo.png',
    'http://www.langlang2017.com/img/langlang1.png'
]


#创建线程
thread_list = []
for url in url_list:
    t = Thread(target=downloader,args=(url,))
    t.start()#启动线程
    thread_list.append(t)

for t in thread_list:
    t.join()



print('~~~~~~主线程执行完成~~~~~~~')