发送简单的请求：

发送带header的请求：

 发送带参数的请求：

实战（贴吧爬虫）：

import requests

class TiebaSpider:
    #构造函数，传入想要查询的贴吧名字和查询前num页，定义后面方法需要用的属性
    def __init__(self,tieba_name,tieba_num):
        self.tieba_num = tieba_num
        self.tieba_name = tieba_name
        #下面为url访问的格式,kw为贴吧名,pn为代表页数，贴吧可查首页pn=0,第一页50，第二页100,以此类推
        self.url_temp = "https://tieba.baidu.com/f?kw=" + tieba_name + "&ie=utf-8&pn={}"
        #模仿网页访问贴吧
        self.headers = {"User-Agent":"Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 "
                        "(KHTML, like Gecko) Chrome/77.0.3865.120 Safari/537.36"}

    #获取url列表
    def get_urlList(self):
        url_list = []
        for i in range(self.tieba_num):
            url_list.append(self.url_temp.format(i * 50))
        return url_list

    #访问网页，解析网页,返回
    def parse_url(self,url):
        response = requests.get(url,headers=self.headers)
        return response.text #或者response.content.decode('utf-8')

    #保存网页
    def save_html(self,html_str,page_num):
        file_path = "{}-第{}页.html".format(self.tieba_name,page_num)
        with open(file_path,'w',encoding='utf-8') as f:
            f.write(html_str)

    def run(self):
        url_list = self.get_urlList()
        for url in url_list:
            html_str = self.parse_url(url)  #保存的内容
            page_num = url_list.index(url) + 1  #文件的页码
            self.save_html(html_str,page_num)

def main():
    tieba_name = input('请输入想查询的贴吧名：')
    tieba_num = int(input('请输入想要查询前几页：'))
    tieba = TiebaSpider(tieba_name, tieba_num)
    tieba.run()

if __name__ == '__main__':
    main()