爬取网站图片，并下载保存到指定文件夹

源码如下：

# -*- coding: utf-8 -*-
# @Time    : 2017/5/18 17:38
# @Author  : xiaojingjing
# @Site    : 
# @File    : finde_mmimg.py
# @Software: PyCharm
import  urllib.request
import  os,shutil

def url_open(url):
    req=urllib.request.Request(url)
    req.add_header('User-Agent','Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.133 Safari/537.36')
    response=urllib.request.urlopen(url)
    html=response.read()
    return html


def get_page(url):
    html=url_open(url).decode('utf-8')
    a=html.find('current-comment-page')+23
    b=html.find(']',a)

    return html[a:b]

def find_imgs(url):
    html=url_open(url).decode('utf-8')
    img_addrs=[]
    a=html.find('img src=')

    while a!= -1:
        b=html.find('.jpg',a,a+255)
        if b!=-1:
            img_addrs.append('http:'+html[a+9:b+4])
        else:
            b=a+9

        a=html.find('img src=',b)
    print(img_addrs)
    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_mm(folder='ooxx'):
    pages=int(input("请输入需要下载多少页："))
    print("判断文件夹是否存在..........")
    if os.path.exists('ooxx'):
        print("存在,删除中··········")
        shutil.rmtree('ooxx')
        print("删除完毕！")
    else:
        print("新建文件夹",folder,"中...........")
        os.mkdir(folder)
        os.chdir(folder)
        print("新建完成..............")


    url="http://jandan.net/ooxx/"
    page_num=int(get_page(url))

    for i in range(pages):
        page_num -=i
        page_url=url+'page-'+str(page_num)+'#comments'
        img_addrs=find_imgs(page_url)
        save_imgs(folder,img_addrs)


if __name__=='__main__':
    download_mm()