基python实现多线程网页爬虫
发布时间:2020-12-17 17:24:21 所属栏目:Python 来源:网络整理
导读:今天PHP站长网 52php.cn把收集自互联网的代码分享给大家,仅供参考。 #!/usr/bin/env python#coding=utf-8import threadingimport urllibimport reimport timeg_mutex=threading.Condition()g_pages=[] #从中解析所有url
以下代码由PHP站长网 52php.cn收集自互联网 现在PHP站长网小编把它分享给大家,仅供参考 #!/usr/bin/env python #coding=utf-8 import threading import urllib import re import time g_mutex=threading.Condition() g_pages=[] #从中解析所有url链接 g_queueURL=[] #等待爬取的url链接列表 g_existURL=[] #已经爬取过的url链接列表 g_failedURL=[] #下载失败的url链接列表 g_totalcount=0 #下载过的页面数 class Crawler: def __init__(self,crawlername,url,threadnum): self.crawlername=crawlername self.url=url self.threadnum=threadnum self.threadpool=[] self.logfile=file("log.txt",'w') def craw(self): global g_queueURL g_queueURL.append(url) depth=0 print self.crawlername+" 启动..." while(len(g_queueURL)!=0): depth+=1 print 'Searching depth ',depth,'...nn' self.logfile.write("URL:"+g_queueURL[0]+"........") self.downloadAll() self.updateQueueURL() content='n>>>Depth '+str(depth)+':n' self.logfile.write(content) i=0 while i<len(g_queueURL): content=str(g_totalcount+i)+'->'+g_queueURL[i]+'n' self.logfile.write(content) i+=1 def downloadAll(self): global g_queueURL global g_totalcount i=0 while i<len(g_queueURL): j=0 while j<self.threadnum and i+j < len(g_queueURL): g_totalcount+=1 threadresult=self.download(g_queueURL[i+j],str(g_totalcount)+'.html',j) if threadresult!=None: print 'Thread started:',i+j,'--File number =',g_totalcount j+=1 i+=j for thread in self.threadpool: thread.join(30) threadpool=[] g_queueURL=[] def download(self,filename,tid): crawthread=CrawlerThread(url,tid) self.threadpool.append(crawthread) crawthread.start() def updateQueueURL(self): global g_queueURL global g_existURL newUrlList=[] for content in g_pages: newUrlList+=self.getUrl(content) g_queueURL=list(set(newUrlList)-set(g_existURL)) def getUrl(self,content): reg=r'"(http://.+?)"' regob=re.compile(reg,re.DOTALL) urllist=regob.findall(content) return urllist class CrawlerThread(threading.Thread): def __init__(self,tid): threading.Thread.__init__(self) self.url=url self.filename=filename self.tid=tid def run(self): global g_mutex global g_failedURL global g_queueURL try: page=urllib.urlopen(self.url) html=page.read() fout=file(self.filename,'w') fout.write(html) fout.close() except Exception,e: g_mutex.acquire() g_existURL.append(self.url) g_failedURL.append(self.url) g_mutex.release() print 'Failed downloading and saving',self.url print e return None g_mutex.acquire() g_pages.append(html) g_existURL.append(self.url) g_mutex.release() if __name__=="__main__": url=raw_input("请输入url入口:n") threadnum=int(raw_input("设置线程数:")) crawlername="小小爬虫" crawler=Crawler(crawlername,threadnum) crawler.craw() 以上内容由PHP站长网【52php.cn】收集整理供大家参考研究 如果以上内容对您有帮助,欢迎收藏、点赞、推荐、分享。 (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |