#爬取站长素材中的免费建立模板import requestsfrom lxml import etreeimport randomheaders = {    "User-Agent": "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36",    "Connection": "close"      # 防止连接池 一直被占用着  请求结束后马上断开连接  释放连接池中的资源}#第一页的urlurl_page_one = 'http://sc.chinaz.com/jianli/free.html'#其他页 通用的urlurl_demo = 'http://sc.chinaz.com/jianli/free_%d.html'start_page = int(input('enter a start page num:'))end_page = int(input('enter a end page num:'))for i in range(start_page,end_page+1):    if i == 1:        url = url_page_one    else:        url = url_demo%i        response = requests.get(url=url, headers=headers)    response.encoding = 'utf-8'    page_text = response.text        #解析详情页的名称 和 url    tree = etree.HTML(page_text)    div_list = tree.xpath('//div[@id="container"]/div')        for div in div_list:        detail_url = div.xpath('./p/a/@href')[0]        name = div.xpath('./p/a/text()')[0]                #对详情页发起请求        detail_page_text = requests.get(url=detail_url,headers=headers).text                #对详情页的源码数据进行解析：下载地址对应的url        tree = etree.HTML(detail_page_text)                #找到所有的下载地址        li_list = tree.xpath('//div[@class="clearfix mt20 downlist"]/ul/li')                #随机选取一个li标签（li标签中包含了下载地址的url）        li = random.choice(li_list)           download_url = li.xpath('./a/@href')[0]                #进行简历下载  相当于点击下载连接        data = requests.get(url=download_url, headers=headers).content    #content 是以流的形式获取数据        name = name+ ".rar"                with open(name,"wb") as fp:            fp.write(data)                print(name,"下载成功")