day10_多线程3

Posted 2020-10-27 laosun0204

# 多线程把六个网站写到文件里(并行)

import requests,time,threading

def write_html(url,name):

    r = requests.get(url)

    with open(name,‘w‘,encoding = ‘utf8‘) as f:

        f.write(r.text)

urls = [‘www.nnzhp.cn‘,‘www.besttest.cn‘,‘www.imdsx.cn‘,‘sb.nnzhp.cn‘,‘bbs.besttest.cn‘,‘video.besttest.cn‘] #六个网站URL

lis = [] # 存放每个线程

start_time = time.time()

for url in urls: # 循环每个url

    new_file = ‘http://‘ + url

    file_name = url + ‘.html‘

    t = threading.Thread(target = write_html,args = (new_url,file_name)) # 实例化一个线程

    lis.append(t)

    t.start() # 启动一个线程

# 启动六个线程，让他们跑着，主线程等他们，join就是主线程在等待每个子线程执行完成

for obj in lis:

   obj.join() # join必须放在启动的六个线程外面

end_time = time.time()

print(‘程序总共运行了‘,end_time - start_time)

主线程等待的意思是让子线程把所有的页面都爬完，然后主线程发送邮件