Python多线程爬虫获取糗事百科段子(Python爬虫实战2)

2018-02-22 20:08:56来源:cnblogs.com作者:HappyLab人点击

分享

1. 多进程爬虫

  对于数据量较大的爬虫,对数据的处理要求较高时,可以采用python多进程或多线程的机制完成,多进程是指分配多个CPU处理程序,同一时刻只有一个CPU在工作,多线程是指进程内部有多个类似"子进程"同时在协同工作。python中有多种多个模块可完成多进程和多线程的工作,此处此用multiprocessing模块完成多线程爬虫,测试过程中发现,由于站点具有反爬虫机制,当url地址和进程数目较多时,爬虫会报错。

2. 代码内容

#!/usr/bin/python#_*_ coding:utf _*_import reimport time import requestsfrom multiprocessing import Poolduanzi_list = []def get_web_html(url):	'''	@params:获取url地址web站点的html数据	'''	headers = {"User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0"}	try:		req = requests.get(url,headers=headers)		if req.status_code == 200:response = req.text.encode('utf8')	except Exception as e:		print e	return responsedef scrap_qiushi_info(url):	'''	@params:url,获取段子数据信息	'''	html = get_web_html(url)	usernames = re.findall(r'<h2>(.*?)</h2>',html,re.S|re.M)	levels = re.findall('<div class="articleGender /w*Icon">(/d+)</div>',html,re.S|re.M)	laugh_counts = re.findall('<span class="stats-vote">.*?<i class="number">(/d+)</i>',html,re.S|re.M)	comment_counts = re.findall('<i class="number">(/d+)</i> 评论',html,re.S|re.M)	contents = re.findall('<div class="content">.*?<span>(.*?)</span>',html,re.S|re.M)	for username,level,laugh_count,comment_count,content in zip(usernames,levels,laugh_counts,comment_counts,contents):		information = {"username": username.strip(),"level": level.strip(),"laugh_count": laugh_count.strip(),"comment_count": comment_count.strip(),"content": content.strip()		}		duanzi_list.append(information)	time.sleep(1)	return duanzi_listdef normal_scapper(url_lists):	'''	定义调用函数,使用普通的爬虫函数爬取数据	'''	begin_time = time.time()	for url in url_lists:		scrap_qiushi_info(url)	end_time = time.time()	print "普通爬虫一共耗费时长:%f" % (end_time - begin_time)def muti_process_scapper(url_lists,process_num=2):	'''	定义多进程爬虫调用函数,使用mutiprocessing模块爬取web数据	'''	begin_time = time.time()	pool = Pool(processes=process_num)	pool.map(scrap_qiushi_info,url_lists)	end_time = time.time()	print "%d个进程爬虫爬取所耗费时长为:%s" % (process_num,(end_time - begin_time))def main():	'''	定义main()函数,程序入口,通过列表推倒式获取url地址,调用爬虫函数	'''	url_lists = ['https://www.qiushibaike.com/text/page/{}'.format(i) for i in range(1,11)]	normal_scapper(url_lists)	muti_process_scapper(url_lists,process_num=2)if __name__ == "__main__":	main()

 3. 多线程机制

最新文章

123

最新摄影

微信扫一扫

第七城市微信公众平台