Python网络爬虫实例2：用Python访问百度贴吧保存图片

 

1.进入一个百度贴吧，并打开一个帖子，复制该网址

2.找到图片，单击右键选择审查元素，复制图片网址前的字符串

img class="BDE_Image" src=

3.编写脚本文件

将网址复制放入 download函数中的url中

 url = 'https://tieba.baidu.com/p/4765578807'

将复制的字符串放入find_img函数中赋值给a的语句：

a = html.find('img class="BDE_Image" src=')  

更改要保存的页数

def download(folder = 'picture',pages = 3):  

整体代码如下：

import urllib.request
import os
def url_open(url):
    req = urllib.request.Request(url)
    req.add_header('User-Agent','Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.90 Safari/537.36 2345Explorer/9.3.2.17331 ')
    response = urllib.request.urlopen(req)
    html = response.read()
    return html
     

def find_imgs(url):
    html = url_open(url).decode('utf-8')
    img_addrs = []
    a = html.find('img class="BDE_Image" src=')  
    while a != -1:
        b = html.find('.jpg',a,a+255)
        img_addrs.append(html[a+27:b+4])   ##img class="BDE_Image" src= 共26个字符，因此img_addrs应从第27个字符开始，.jpg共4个字符
        a = html.find('img class="BDE_Image" src=',b)
    return img_addrs
            

def save_imgs(folder,img_addrs):
    for each in img_addrs:
        filename =  each.split('/')[-1]   
        with open(filename,'wb') as f:
            img = url_open(each)
            f.write(img)
    

def download(folder = 'picture',pages = 3):
    os.mkdir(folder)
    os.chdir(folder)
    url = 'https://tieba.baidu.com/p/4765578807'
    page_num = 0
    
    for i in range(pages):
        page_num += 1 
        ##page_url = url +  str(page_num)
        page_url = url + '?pn=' + str(page_num)
        img_addrs = find_imgs(page_url)
        save_imgs(folder,img_addrs)

if __name__ == '__main__':
    download()

4.编译运行

运行结果如下，图片被保存入指定文件夹