2017.08.14 Python爬虫实战之Bs4获取百度贴吧内容

1.目标分析：http://tieba.baidu.com/f?kw=%E6%9D%83%E5%8A%9B%E7%9A%84%E6%B8%B8%E6%88%8F&ie=utf-8

说明浏览器接受的是utf8的编码

（1）在浏览器上单击下一页，pn就会增加50：http://tieba.baidu.com/f?kw=%E6%9D%83%E5%8A%9B%E7%9A%84%E6%B8%B8%E6%88%8F&ie=utf-8&pn=50

（2）查看帖子和源代码：

2.项目实施：

（1）创建项目：查看项目所需的标签项：

 （2）项目文件结构：

（3）项目源代码，文件    getCommetInfo.py：

#! /usr/bin/env python
#-*- coding:utf-8 -*-

import urllib2
from bs4 import BeautifulSoup
from mylog import MyLog as mylog

class Item(object):
    title=None  #帖子标题
    firstAuthor=None #帖子创建者
    firstTime=None   #帖子创建时间
    reNum=None   #总回复数
    content=None  #最后回复内容
    lastAuthor=None  #最后回复者
    lastTime=None   #最后回复时间

class GetTiebaInfo(object):
    def __init__(self,url):
        self.url=url
        self.log=mylog()
        self.pageSum=5
        self.urls=self.getUrls(self.pageSum)
        self.items=self.spider(self.urls)
        self.pipelines(self.items)

    def getUrls(self,pageSum):
        urls=[ ]
        pns=[str(i*50) for i in range(pageSum)]
        ul=self.url.split('=')
        for pn in pns:
            ul[-1]=pn
            url='='.join(ul)
            urls.append(url)
        self.log.info(u'获取URLS成功')
        return urls

    def spider(self,urls):
        items=[ ]
        for url in urls:
            htmlContent=self.getResponseContent(url)
            soup=BeautifulSoup(htmlContent,'lxml')
            tagsli=soup.find_all('li',attrs={'class':' j_thread_list clearfix'})

            for tag in tagsli:
                item=Item()
                item.title=tag.find('a',attrs={'class':'j_th_tit '}).get_text().strip()
                item.firstAuthor=tag.find('span',attrs={'class':'frs-author-name-wrap'}).a.get_text().strip()
                item.firstTime=tag.find('span',attrs={'title':u'创建时间'.encode('utf8')}).get_text().strip()
                item.reNum=tag.find('span',attrs={'title':u'回复'.encode('utf8')}).get_text().strip()
                item.content=tag.find('div',attrs={'class':'threadlist_abs threadlist_abs_onlyline '}).get_text().strip()
                item.lastAuthor=tag.find('span',attrs={'class':'tb_icon_author_rely j_replyer'}).a.get_text().strip()
                item.lastTime=tag.find('span',attrs={'title':u'最后回复时间'.encode('utf8')}).get_text().strip()

                items.append(item)
                self.log.info(u'获取标题<<%s>>的项成功' %item.title)

        return items

    def pipelines(self,items):
         fileName=u'百度贴吧_权力的游戏.txt'.encode('GBK')
         with open(fileName,'w') as fp:
             for item in items:
                 fp.write('title:%s 	 author:%s 	 firstTime:%s 
 content:%s 
 return:%s 
 lastAuthor:%s 	 lastTime:%s 



'
                          %(item.title.encode('utf8'),item.firstAuthor.encode('utf8'),item.firstTime.encode('utf8'),item.content.encode('utf8'),
                            item.reNum.encode('utf8'),item.lastAuthor.encode('utf8'),item.lastTime.encode('utf8'))
                          )
                 self.log.info(u'标题为<<%s>>的项输入到"%s"成功' %(item.title,fileName.decode('GBK')))



    def getResponseContent(self,url):
         try:
             response=urllib2.urlopen(url.encode('utf8'))
         except:
             self.log.error(u'python 返回 URL:%s 数据失败' %url)
         else:
             self.log.info(u'Python 返回URL:%s A数据成功' %url)
             return response.read()
if __name__ == '__main__':
    url=u'http://tieba.baidu.com/f?kw=%E6%9D%83%E5%8A%9B%E7%9A%84%E6%B8%B8%E6%88%8F&ie=utf-8&pn=50'
    GTI=GetTiebaInfo(url)


（4）项目源代码，文件mylog.py：

#! /usr/bin/env python
#-*- coding:utf-8 -*-

import logging
import getpass
import sys

class MyLog(object):
    ###########类MyLog的构造函数
    def __init__(self):
        self.user=getpass.getuser()
        self.logger=logging.getLogger(self.user)
        self.logger.setLevel(logging.DEBUG)

    #########日志文件名
        self.logFile=sys.argv[0][0:-3]+'.log'
        self.formatter=logging.Formatter('%(asctime)-12s %(levelname)-8s %(name)-10s %(message)-12s 
')

    #########日志显示到屏幕并输出到日志文件中
        self.logHand=logging.FileHandler(self.logFile,encoding='utf8')
        self.logHand.setFormatter(self.formatter)
        self.logHand.setLevel(logging.DEBUG)


        self.logHandSt=logging.StreamHandler()
        self.logHandSt.setFormatter(self.formatter)
        self.logHandSt.setLevel(logging.DEBUG)

        self.logger.addHandler(self.logHand)
        self.logger.addHandler(self.logHandSt)
    #####日志的5个级别对应以下5个函数
    def debug(self,msg):
        self.logger.debug(msg)
    def info(self,msg):
        self.logger.info(msg)

    def warn(self,msg):
        self.logger.warn(msg)

    def error(self,msg):
        self.logger.error(msg)
    def critical(self,msg):
        self.logger.critical(msg)


if __name__ == '__main__':
    mylog=MyLog()
    mylog.debug(u"I'm debug 测试中文")
    mylog.info("I'm info")
    mylog.warn("I'm warn")
    mylog.error(u"I'm error 测试中文 ")
    mylog.critical("I'm critical")

（5）右击文件运行结果：

3.代码分析：

 主程序getCommetInfo.py部分解析：