一个Python小白5个小时爬虫经历

import urllib.parse
import urllib.request

# params  CategoryId=808 CategoryType=SiteHome ItemListActionName=PostList PageIndex=3 ParentCategoryId=0 TotalPostCount=4000
def getHtml(url,values):
    user_agent='Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/52.0.2743.82 Safari/537.36'
    headers = {'User-Agent':user_agent}
    data = urllib.parse.urlencode(values)
    response_result = urllib.request.urlopen(url+'?'+data).read()
    html = response_result.decode('utf-8')
    return html

#获取数据
def requestCnblogs(index):
    print('请求数据')
    url = 'http://www.cnblogs.com/mvc/AggSite/PostList.aspx'
    value= {
         'CategoryId':808,
         'CategoryType' : 'SiteHome',
         'ItemListActionName' :'PostList',
         'PageIndex' : index,
         'ParentCategoryId' : 0,
        'TotalPostCount' : 4000
    }
    result = getHtml(url,value)
    return result

<div class="post_item"> <div class="digg"> <div class="diggit" onclick="DiggPost('hyper-xl',6417741,281238,1)"> <span class="diggnum" id="digg_count_6417741">1</span> </div> <div class="clear"></div> <div id="digg_tip_6417741" class="digg_tip"></div> </div> <div class="post_item_body"> <h3><a class="titlelnk" href="http://www.cnblogs.com/hyper-xl/p/6417741.html" target="_blank">Python 字符串格式化</a></h3> <p class="post_item_summary"> <a href="http://www.cnblogs.com/hyper-xl/" target="_blank"> <img width="48" height="48" class="pfs" src="//pic.cnblogs.com/face/795666/20160421231717.png" alt="" /> </a> 转载请注明出处 Python2.6+ 增加了str.format函数，用来代替原有的'%'操作符 。它使用比'%'更加直观、灵活。下面详细介绍一下它的使用方法。 下面是使用'%'的例子: 格式很像C语言的printf是不是？由于'%'是一个操作符，只能在左右 两边各放一个参数，因此右边多个值需要用元组或 ... </p> <div class="post_item_foot"> <a href="http://www.cnblogs.com/hyper-xl/" class="lightblue">新月的力量_141</a> 发布于 2017-02-19 23:07 <span class="article_comment"> <a href="http://www.cnblogs.com/hyper-xl/p/6417741.html#commentform" title="" class="gray"> 评论(0) </a> </span> <span class="article_view"> <a href="http://www.cnblogs.com/hyper-xl/p/6417741.html" class="gray"> 阅读 (138) </a> </span> </div> </div> <div class="clear"></div> </div>

from bs4 import BeautifulSoup import request import re #解析最外层 def blogParser(index): cnblogs = request.requestCnblogs(index) soup = BeautifulSoup(cnblogs, 'html.parser') all_div = soup.find_all('div', attrs={'class': 'post_item_body'}, limit=20) blogs = [] #循环div获取详细信息 for item in all_div: blog = analyzeBlog(item) blogs.append(blog) return blogs #解析每一条数据 def analyzeBlog(item): result = {} a_title = find_all(item,'a','titlelnk') if a_title is not None: # 博客标题 result["title"] = a_title[0].string # 博客链接 result["href"] = a_title[0]['href'] p_summary = find_all(item,'p','post_item_summary') if p_summary is not None: # 简介 result["summary"] = p_summary[0].text footers = find_all(item,'div','post_item_foot') footer = footers[0] # 作者 result["author"] = footer.a.string # 作者url result["author_url"] = footer.a['href'] str = footer.text time = re.findall(r"发布于 .+? .+? ", str) result["create_time"] = time[0].replace('发布于 ','') comment_str = find_all(footer,'span','article_comment')[0].a.string result["comment_num"] = re.search(r'\d+', comment_str).group() view_str = find_all(footer,'span','article_view')[0].a.string result["view_num"] = re.search(r'\d+', view_str).group() return result def find_all(item,attr,c): return item.find_all(attr,attrs={'class':c},limit=1)

import match import os import datetime import json def writeToTxt(list_name,file_path): try: #这里直接write item 即可，不要自己给序列化在写入，会导致json格式不正确的问题 fp = open(file_path,"w+",encoding='utf-8') l = len(list_name) i = 0 fp.write('[') for item in list_name: fp.write(item) if i<l-1: fp.write(',\n') i += 1 fp.write(']') fp.close() except IOError: print("fail to open file") #def getStr(item): # return json.dumps(item).replace('\'','\"')+',\n' def saveBlogs(): for i in range(1,2): print('request for '+str(i)+'...') blogs = match.blogParser(i,5) #保存到文件 path = createFile() writeToTxt(blogs,path+'/blog_'+ str(i) +'.json') print('第'+ str(i) +'页已经完成') return 'success' def createFile(): date = datetime.datetime.now().strftime('%Y-%m-%d') path = '/'+date if os.path.exists(path): return path else: os.mkdir(path) return path result = saveBlogs() print(result)