运用python3中的urllib爬取贴吧的图片

　　运用python3中的urllib爬取贴吧的图片：

import urllib
import urllib.request
import lxml
import lxml.etree
import re
from urllib import parse
#抓取贴吧页面数量信息
def gettiebalistnumbers(name):    #计算搜索的关键词有多少页  输入名字  返回页数
    url="https://tieba.baidu.com/f?"
    headers = {"User-Agent": "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36 QIHU 360SE"}  # header 字典形式
    word = {"kw": name}  # 接口   贴吧的名字
    word = parse.urlencode(word)  # 编码成字符串
    url = url + word  # 拼接url
    request = urllib.request.Request(url, headers=headers)  # 发送请求
    # 也可以通过调用Request.add_header()  添加/修改一个特定的  header
    request.add_header("Connection", "keep-alive")  # 一直活着
    response = urllib.request.urlopen(request)  # 打开请求
    data = response.read().decode("utf-8")  # 读取数据
    print(response.code)  # 可以查看相应状态码

    restr = "<span class=\"card_infoNum\">([\s\S]*?)</span>"  # 正则这个贴吧有多少帖子
    regex = re.compile(restr, re.IGNORECASE)
    mylist = regex.findall(data)  #寻找页面所有符合条件的
    tienumbers = mylist[0].replace(",","")  #替换逗号
    tienumbers = eval(tienumbers)   #str转化为数字

    restr = "<span class=\"card_menNum\">([\s\S]*?)</span>"  # 正则关注贴吧的数
    regex = re.compile(restr, re.IGNORECASE)
    mylist = regex.findall(data)  # 寻找页面所有符合条件的
    Peoplenumbers = mylist[0].replace(",", "")  # 替换逗号
    Peoplenumbers = eval(Peoplenumbers)  # str转化为数字
    return tienumbers,Peoplenumbers

def gettiebalist(name):   #抓取所有的符合name的页数  输入搜索关键词，返回所有的页数url
    numberstuple=gettiebalistnumbers(name)   #(元组）
    tienumbers=numberstuple[1]   #帖子的数量
    word = {"kw": name}  # 接口   贴吧的名字
    word = parse.urlencode(word)  # 编码成字符串
    tiebalist = []
    if tienumbers%53==0:   #生成页面列表
        for i in range(tienumbers//53):
            tiebalist.append("https://tieba.baidu.com/f?"+word+"&pn="+str(i*50))
    else:
        for i in range(tienumbers//53+1):
            tiebalist.append("https://tieba.baidu.com/f?"+word+"&pn="+str(i*50))
    #print(tiebalist)
    return tiebalist
def geturllistformpage(url):  # 抓取页面的每个帖子url  输入一页url 返回列表内的的所有url
    headers = {"User-Agent": "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0);"}
    request = urllib.request.Request(url, headers=headers)  # 发起请求，
    # 也可以通过调⽤Request.add_header() 添加/修改⼀个特定的 header
    response = urllib.request.urlopen(request)
    data = response.read().decode("utf-8", "ignore")  # 打开请求，抓取数据
    # print(response.code)  # 可以查看响应状态码

    restr = "<ul id=\"thread_list\" class=\"threadlist_bright j_threadlist_bright\">([\s\S]*?)<div class=\"thread_list_bottom clearfix\">"  # 正则表达式，（）只要括号内的数据
    regex = re.compile(restr, re.IGNORECASE)
    mylist = regex.findall(data)
    # print(mylist[0])#抓取整个表格

    restr = "href=\"/p/(\d+)\""  # 正则表达式，（）只要括号内的数据
    regex = re.compile(restr, re.IGNORECASE)
    urltitlelist = regex.findall(data)  #抓取的url变化的数字
    urllist = []
    for title in urltitlelist:
        urllist.append("http://tieba.baidu.com/p/" + title)  # 拼接链接 得到每个页面的帖子url列表
    return urllist

def urllistfrompage(url):  #一个帖子页面的所有页数，输入一个帖子url 返回一个帖子所有页数的url列表
    headers = {"User-Agent": "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36 QIHU 360SE"}  # header 字典形式
    request = urllib.request.Request(url, headers=headers)
    response = urllib.request.urlopen(request)
    data = response.read()#.decode("utf-8","ignore")
    mytree=lxml.etree.HTML(data)
    numbers=eval(mytree.xpath("//*[@class =\"l_reply_num\"]//span[last()]/text()")[0])
    urllist=[]
    for i in range(1,numbers+1):
        urllist.append(url+"?pn="+str(i))
    return urllist
def getjpglistfrompage(url):  #输入一个分页的url  提取所有的图片url 并保存到本地
    headers = {"User-Agent": "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36 QIHU 360SE"}  # header 字典形式
    request = urllib.request.Request(url, headers=headers)
    response = urllib.request.urlopen(request)
    data = response.read()
    mytree=lxml.etree.HTML(data)
    jpgurllist=mytree.xpath("//*[@class=\"BDE_Image\"]/@src")
    return jpgurllist

name="关晓彤"
jpgnumbers=0
for souurl in gettiebalist(name):
    sousurl=geturllistformpage(souurl)
    for fenurl in sousurl:
        jpgallurl=urllistfrompage(fenurl)
        for rev in jpgallurl:
            for jpgurl in getjpglistfrompage(rev):
                jpgnumbers += 1
                urllib.request.urlretrieve(jpgurl, "jpg/" + str(jpgnumbers) + ".jpg")