Python爬虫——抓取贴吧帖子

时间：2023-03-08 16:49:21
Python爬虫——抓取贴吧帖子

抓取百度贴吧帖子

按照这个学习教程，一步一步写出来，中间遇到很多的问题，一一列举

首先， 获得 标题 和 贴子总数

# -*- coding:utf-8 -*-

#!/user/bin/python

import urllib

import urllib2

import re

class BDTB:

    #初始化，传入基地址，是否只看楼主的参数

    def __init__(self, baseUrl, seeLZ):

        self.baseURL = baseUrl

        self.seeLZ = '?see_lz=' + str(seeLZ)

    #传入页码，获取该页帖子的代码

    def getPage(self, pageNum):

        try:

            url = self.baseURL + self.seeLZ + '&pn=' + str(pageNum)

            request = urllib2.Request(url)

            response = urllib2.urlopen(request)

            return response.read()

        except urllib2.URLError, e:

            if hasattr(e, "reason"):

                print u"连接百度贴吧失败,错误原因", e.reason

                return None

    def getTitle(self):

        page = self.getPage(1)

        pattern = re.compile('<h3 class="core_title_txt.*?>(.*?)</h3>', re.S)

        result = re.search(pattern, page)

        if result:

            print result.group(1)

            return result.group(1).strip()

        else:

            return None

    #得到帖子页数

    def getPageNum(self):

        page = self.getPage(1)

        pattern = re.compile('<li class="l_reply_num.*?<span.*?>(.*?)</span',re.S)

        result = re.search(pattern, page)

        if result:

            print "回复个数："

            print result.group(1)

            return result.group(1).strip()

        else:

            return None

baseURL = 'http://tieba.baidu.com/p/3138733512'

bdtb = BDTB(baseURL, 1)

bdtb.getTitle()

bdtb.getPageNum()

PS：我用的火狐浏览器，查看网页源代码，鼠标右击查看 获得 快捷键 Ctrl-U

接下来 抓取 楼层的内容，写好的 程序如下

import urllib

import urllib2

import re

class BDTB:

    #初始化，传入基地址，是否只看楼主的参数

    def __init__(self, baseUrl, seeLZ):

        self.baseURL = baseUrl

        self.seeLZ = '?see_lz=' + str(seeLZ)

    #传入页码，获取该页帖子的代码

    def getPage(self, pageNum):

        try:

            url = self.baseURL + self.seeLZ + '&pn=' + str(pageNum)

            request = urllib2.Request(url)

            response = urllib2.urlopen(request)

            return response.read()

        except urllib2.URLError, e:

            if hasattr(e, "reason"):

                print u"连接百度贴吧失败,错误原因", e.reason

                return None

    def getTitle(self):

        page = self.getPage(1)

        pattern = re.compile('<h3 class="core_title_txt.*?>(.*?)</h3>', re.S)

        result = re.search(pattern, page)

        if result:

            print result.group(1)

            return result.group(1).strip()

        else:

            return None

    #得到帖子页数

    def getPageNum(self):

        page = self.getPage(1)

        pattern = re.compile('<li class="l_reply_num.*?<span.*?>(.*?)</span',re.S)

        result = re.search(pattern, page)

        if result:

            print "回复个数："

            print result.group(1)

            return result.group(1).strip()

        else:

            return None

    def getContent(self,page):

        pattern = re.compile('<div id="post_content_.*? class="d_post_content j_d_post_content ">(.*?)</div>',re.S)

        items = re.findall(pattern,page)

        for item in items:

            print item

baseURL = 'http://tieba.baidu.com/p/3138733512'

bdtb = BDTB(baseURL, 1)

bdtb.getTitle()

bdtb.getPageNum()

bdtb.getContent(1)

但是运行之后一直报错，如下图：

Python爬虫——抓取贴吧帖子

检查代码无数次后，终于.....发现 getContent中 没有获取页码 T_T  在这个函数首句加上

page = self.getPage(1)

即可！！！

终于得到了内容部分，用一下工具类 可将乱七八糟的图片什么的代码去掉

#处理页面标签类

class Tool:

    #去除img标签,7位长空格

    removeImg = re.compile('<img.*?>| {7}|')

    #删除超链接标签

    removeAddr = re.compile('<a.*?>|</a>')

    #把换行的标签换为\n

    replaceLine = re.compile('<tr>|<div>|</div>|</p>')

    #将表格制表<td>替换为\t

    replaceTD= re.compile('<td>')

    #把段落开头换为\n加空两格

    replacePara = re.compile('<p.*?>')

    #将换行符或双换行符替换为\n

    replaceBR = re.compile('<br><br>|<br>')

    #将其余标签剔除

    removeExtraTag = re.compile('<.*?>')

    def replace(self,x):

        x = re.sub(self.removeImg,"",x)

        x = re.sub(self.removeAddr,"",x)

        x = re.sub(self.replaceLine,"\n",x)

        x = re.sub(self.replaceTD,"\t",x)

        x = re.sub(self.replacePara,"\n    ",x)

        x = re.sub(self.replaceBR,"\n",x)

        x = re.sub(self.removeExtraTag,"",x)

        #strip()将前后多余内容删除

        return x.strip()

最后最后，就是这样的了..

# -*- coding:utf-8 -*-

#!/user/bin/python

import urllib

import urllib2

import re

#处理页面标签类

class Tool:

    #去除img标签,7位长空格

    removeImg = re.compile('<img.*?>| {7}|')

    #删除超链接标签

    removeAddr = re.compile('<a.*?>|</a>')

    #把换行的标签换为\n

    replaceLine = re.compile('<tr>|<div>|</div>|</p>')

    #将表格制表<td>替换为\t

    replaceTD= re.compile('<td>')

    #把段落开头换为\n加空两格

    replacePara = re.compile('<p.*?>')

    #将换行符或双换行符替换为\n

    replaceBR = re.compile('<br><br>|<br>')

    #将其余标签剔除

    removeExtraTag = re.compile('<.*?>')

    def replace(self,x):

        x = re.sub(self.removeImg,"",x)

        x = re.sub(self.removeAddr,"",x)

        x = re.sub(self.replaceLine,"\n",x)

        x = re.sub(self.replaceTD,"\t",x)

        x = re.sub(self.replacePara,"\n    ",x)

        x = re.sub(self.replaceBR,"\n",x)

        x = re.sub(self.removeExtraTag,"",x)

        #strip()将前后多余内容删除

        return x.strip()

class BDTB:

    #初始化，传入基地址，是否只看楼主的参数

    def __init__(self, baseUrl, seeLZ, floorTag):

        self.baseURL = baseUrl

        self.seeLZ = '?see_lz=' + str(seeLZ)

        self.tool = Tool()

        #全局file变量，文件写入操作对象

        self.file = None

        #楼层标号， 初始化为1

        self.floor = 1

        #默认标题

        self.defaultTitle = u"百度某某贴吧"

        #是否写入楼层分隔符标记

        self.floorTag = floorTag

    #传入页码，获取该页帖子的代码

    def getPage(self, pageNum):

        try:

            url = self.baseURL + self.seeLZ + '&pn=' + str(pageNum)

            request = urllib2.Request(url)

            response = urllib2.urlopen(request)

            return response.read().decode('utf-8')

        except urllib2.URLError, e:

            if hasattr(e, "reason"):

                print u"连接百度贴吧失败,错误原因", e.reason

                return None

    #获得帖子标题

    def getTitle(self,page):

        page = self.getPage(1)

        pattern = re.compile('<h3 class="core_title_txt.*?>(.*?)</h3>', re.S)

        result = re.search(pattern, page)

        if result:

            #print result.group(1)

            return result.group(1).strip()

        else:

            return None

    #得到帖子页数

    def getPageNum(self,page):

        page = self.getPage(1)

        pattern = re.compile('<li class="l_reply_num.*?<span.*?>(.*?)</span',re.S)

        result = re.search(pattern, page)

        if result:

            #print "回复个数："

            #print result.group(1)

            return result.group(1).strip()

        else:

            return None

    #获得帖子的内容

    def getContent(self,page):

        page = self.getPage(1)

        pattern = re.compile('<div id="post_content_.*?>(.*?)</div>',re.S)

        items = re.findall(pattern,page)

        contents = []

        floor = 1

        for item in items:

            content = "\n" + self.tool.replace(item) + "\n"

            contents.append(content.encode('utf-8'))

            #print self.tool.replace(item)

            #floor += 1

        return contents

    def setFileTitle(self,title):

        if title is not None:

            self.file = open(title + ".txt", "w+")

        else:

            self.file = open(self.defaultTitle + ".txt", "w+")

    def writeData(self,contents):

        for item in contents:

            if self.floorTag == '':

                floorline = "\n" + str(self.floor) + u"-------------------------------------\n"

                self.file.write(floorline)

            self.file.write(item)

            self.floor += 1

    def start(self):

        indexPage = self.getPage(1)

        pageNum = self.getPageNum(indexPage)

        title = self.getTitle(indexPage)

        self.setFileTitle(title)

        if pageNum == None:

            print "URL已失效，请重试"

            return

        try:

            print "该帖子共有" + str(pageNum) + "页"

            for i in range(1,int(pageNum) + 1):

                print "正在写入第" + str(i) + "页数据"

                page = self.getPage(i)

                contents = self.getContent(page)

                self.writeData(contents)

        except IOError,e:

            print "写入异常，原因" + e.message

        finally:

            print "Succeed~"

print u"请输入帖子代码"

baseURL = 'http://tieba.baidu.com/p/' + str(raw_input(u'http://tieba.baidu.com/p/'))

seeLZ = raw_input("是否只看楼主，是输入1，否输入0\\n")

floorTag = raw_input("是否写入楼层信息，是输入1，否输入0\\n")

bdtb = BDTB(baseURL, seeLZ,floorTag)

bdtb.start()
关于decode和encode知识，查看 这个
关于raw_input, 查看 这个

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