改编自CSDN博主嗨学编程的文章我用 Python 抓取了 7000 多本电子书
关于requests-html：
requests-html0.1.0
中文文档
requests-html0.2.0

#-*- coding:utf-8 -*-
# python3.7   requests-html2.0 pycharm
import requests_html
import requests
import random
import sys

HOMEURL = "http://www.padsweb.rwth-aachen.de/wvdaalst/publications/"
session = requests_html.Session()
list_url = 'http://www.padsweb.rwth-aachen.de/wvdaalst/publications/publications.html'

USER_AGENTS = [
    "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_3) AppleWebKit/535.20 (KHTML, like Gecko) Chrome/19.0.1036.7 Safari/535.20",
    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.71 Safari/537.1 LBBROWSER",
    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/535.11 (KHTML, like Gecko) Chrome/17.0.963.84 Safari/535.11 LBBROWSER",
    "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.1; WOW64; Trident/5.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; .NET4.0E)",
    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E)",
    "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; Trident/4.0; SV1; QQDownload 732; .NET4.0C; .NET4.0E; 360SE)",
    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; QQDownload 732; .NET4.0C; .NET4.0E)",
    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1",
    "Mozilla/5.0 (iPad; U; CPU OS 4_2_1 like Mac OS X; zh-cn) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5",
    "Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:2.0b13pre) Gecko/20110307 Firefox/4.0b13pre",
    "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:16.0) Gecko/20100101 Firefox/16.0",
    "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.64 Safari/537.11",
    "Mozilla/5.0 (X11; U; Linux x86_64; zh-CN; rv:1.9.2.10) Gecko/20100922 Ubuntu/10.10 (maverick) Firefox/3.6.10"
]


# 获取页面中所有可以下载的论文名及链接中的名字
# 如文件名Timed coloured Petri nets and their application to logistics.pdf
#     链接中的名字：publicationsp7.pdf file
def get_list(url):
    response = session.get(url)
    all_link = response.html.find('#main a')  # 获取页面所有图书详情链接
    # <a href="p7.pdf">Timed coloured Petri nets and their application to logistics.</a>
    for link in all_link:
    # for i in range(1,30):
    #     link=all_link[i]
        href = link.attrs['href']
        hrefText = link.text
        if '.pdf' in href:
            # 处理含有多个'/'的情况，取最后一个斜杠后的部分
            pdfName = str(hrefText).split('/')[-1] + ".pdf"
            if '?' in pdfName:
                pdfName = pdfName.replace('?', '')
            url = HOMEURL + str(href)
            download(pdfName, url)


# 下载论文
def download(pdfName, url):
    # 随机浏览器 User-Agent
    headers = {"User-Agent": random.choice(USER_AGENTS)}
    # 获取文件名
    filename = url.split('/')[-1]
    print("filename:", filename, "fileName:", pdfName)
    # 如果 url 里包含 .pdf
    if ".pdf" in url:
        file = 'd://books/' + pdfName  # 文件路径写死了，运行时当前目录必须有名 book 的文件夹
        try:
            with open(file, 'wb') as f:
                print("正在下载 %s" % filename)
                response = requests.get(url, stream=True, headers=headers)

                # 获取文件大小
                total_length = response.headers.get('content-length')
                # print("链接：",url)
                # print('response.content:',response.content)
                # print(requests.get(url))
                # 如果文件大小不存在，则直接写入返回的文本
                if total_length is None:
                    f.write(response.content)
                    # print("文件为空:",pdfName,"\t",url,'\t',response.content)
                else:
                    # 下载进度条
                    dl = 0
                    total_length = int(total_length)  # 文件大小
                    for data in response.iter_content(chunk_size=4096):  # 每次响应获取 4096 字节
                        dl += len(data)
                        f.write(data)
                        done = int(50 * dl / total_length)
                        sys.stdout.write("\r[%s%s]" % ('=' * done, ' ' * (50 - done)))  # 打印进度条
                        sys.stdout.flush()
        except IOError as e:
            print(e)
        else:
            print(filename + '下载完成！')


if __name__ == '__main__':
    get_list(list_url)

安装requests-html过程中出现的问题

1、cannot import name 'HTMLSession' from 'requests_html' (C:\Users\owlish\AppData\Local\Programs\Python\Python37\lib\site-packages\requests_html.py)
很尴尬，我的文件名叫“requests.py”，和关键字冲突，改个名就行了。
2、pycharm安装后找不到本地已经安装的模块

创建虚拟环境

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