python爬虫爬去贴吧中的所有图片

import urllib.requestfrom lxml import etreeimport osclass tieba_img(object):    def __init__(self,tieba_name,start_index,end_index):        """                   作用：建立类的初始化                   tieba_name：想要爬取得贴吧名字                   start_index：想要从哪一页开始爬去                   end_index：想要爬取得结束页        """        self.tieba_name=tieba_name        self.start_index=start_index        self.end_index=end_index        self.url="http://tieba.baidu.com/f?"    def start(self):        """            作用：贴吧开始的调度器，用来启动爬虫        """        print("开始爬取了:")        self.tieba_spider()    def tieba_spider(self):        """                   作用：用来处理地址的信息        """        for page in range(start_index,end_index+1):            now_page=(page-1)*50            full_name=self.url+"kw="+self.tieba_name+"&pn="+str(now_page)            self.load_page(full_name)    def load_page(self,full_name):        """                   作用：发送http请求，并且进行解析出每个帖子的地址                   full_name：所要爬取的贴吧的页面        """        headers = {            "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/54.0.2840.99 Safari/537.36"        }        my_request=urllib.request.Request(full_name)        html=urllib.request.urlopen(my_request)        content=etree.HTML(html.read().decode("utf-8"))        # print(html.decode("utf-8"))        # print(content)        link_list = content.xpath('//div[@class="t_con cleafix"]/div/div/div/a/@href')        # print(link_list)        for link in link_list:            full_link="https://tieba.baidu.com"+link            print(full_link)            self.load_img(full_link)    def load_img(self,full_link):        """                   作用：发送http请求，并且进行解析出每个图片的地址，并且将地址存入到文件中                   full_link：所要爬取的每个帖子的地址        """        my_request = urllib.request.Request(full_link)        html = urllib.request.urlopen(my_request)        content = etree.HTML(html.read().decode("utf-8"))        # print(html.decode("utf-8"))        # print(content)        link_list = content.xpath("//img[@class='BDE_Image']/@src")        # print(link_list)        with open("d:xxxxxx.txt","a") as f:            for i in link_list:                f.write(str(i)+"\n")if __name__ == '__main__':    tieba_name=input("请输入想要爬取的哪个贴吧:")    start_index=int(input("请输入想要爬取起始页数:"))    end_index=int(input("请输入想要爬取的终止页数:"))    my_tieba=tieba_img(tieba_name,start_index,end_index)    my_tieba.start()