接着第一篇继续学习。
一、数据分类
正确数据：id、性别、活动时间三者都有
放在这个文件里file1 = 'ruisi\correct%s-%s.txt' % (startNum, endNum)
数据格式为293001 男 2015-5-1 19:17
没有时间：有id、有性别，无活动时间放这个文件里file2 = 'ruisi\errTime%s-%s.txt' % (startNum, endNum)
数据格式为2566 女 notime
用户不存在：该id没有对应的用户放这个文件里file3 = 'ruisi\notexist%s-%s.txt' % (startNum, endNum)
数据格式为29005 notexist
未知性别：有id，但是性别从网页上无法得知（经检查，这种情况也没有活动时间）放这个文件里 file4 = 'ruisi\unkownsex%s-%s.txt' % (startNum, endNum)
数据格式 221794 unkownsex
网络错误：网断了，或者服务器故障，需要对这些id重新检查放这个文件里 file5 = 'ruisi\httperror%s-%s.txt' % (startNum, endNum)
数据格式 271004 httperror
如何不间断得爬虫信息
本项目有一个考虑：是不间断爬取信息，如果因为断网、BBS服务器故障啥的，我的爬虫程序就退出的话。那我们还得从间断的地方继续爬，或者更麻烦的是从头开始爬。 所以，我采取的方法是，如果遇到故障，就把这些异常的id记录下来。等一次遍历之后，才对这些异常的id进行重新爬取性别。 本文系列（一）给出了一个 getInfo(myurl, seWord)，通过给定链接和给定正则表达式爬取信息。 这个函数可以用来查看性别的最后活动时间信息。 我们再定义一个安全的爬取函数，不会间断程序运行的，这儿用到try except异常处理。这儿代码试了两次getInfo(myurl, seWord),如果第2次还是抛出异常了，就把这个id保存在file5里面
如果能获取到信息，就返回信息
file5 = 'ruisi\httperror%s-%s.txt' % (startNum, endNum)
def safeGet(myid, myurl, seWord):
try:
return getInfo(myurl, seWord)
except:
try:
return getInfo(myurl, seWord)
except:
httperrorfile = open(file5, 'a')
info = '%d %sn' % (myid, 'httperror')
httperrorfile.write(info)
httperrorfile.close()
return 'httperror'
依次遍历，获取id从[1,300,000]的用户信息
我们定义一个函数，这儿的思路是获取sex和time，如果有sex，进而继续判断是否有time；如果没sex，判断是否这个用户不存在还是性别无法爬取。
其中要考虑到断网或者BBS服务器故障的情况。
url1 = 'http://rs.xidian.edu.cn/home.php?mod=space&uid=%s'
url2 = 'http://rs.xidian.edu.cn/home.php?mod=space&uid=%s&do=profile'
def searchWeb(idArr):
for id in idArr:
sexUrl = url1 % (id) #将%s替换为id
timeUrl = url2 % (id)
sex = safeGet(id,sexUrl, sexRe)
if not sex: #如果sexUrl里面找不到性别，在timeUrl再尝试找一下
sex = safeGet(id,timeUrl, sexRe)
time = safeGet(id,timeUrl, timeRe)
#如果出现了httperror，需要重新爬取
if (sex is 'httperror') or (time is 'httperror') :
pass
else:
if sex:
info = '%d %s' % (id, sex)
if time:
info = '%s %sn' % (info, time)
wfile = open(file1, 'a')
wfile.write(info)
wfile.close()
else:
info = '%s %sn' % (info, 'notime')
errtimefile = open(file2, 'a')
errtimefile.write(info)
errtimefile.close()
else:
#这儿是性别是None，然后确定一下是不是用户不存在
#断网的时候加上这个，会导致4个重复httperror
#可能用户的性别我们无法知道，他没有填写
notexist = safeGet(id,sexUrl, notexistRe)
if notexist is 'httperror':
pass
else:
if notexist:
notexistfile = open(file3, 'a')
info = '%d %sn' % (id, 'notexist')
notexistfile.write(info)
notexistfile.close()
else:
unkownsexfile = open(file4, 'a')
info = '%d %sn' % (id, 'unkownsex')
unkownsexfile.write(info)
unkownsexfile.close()
这儿后期检查发现了一个问题
sex = safeGet(id,sexUrl, sexRe)
if not sex:
sex = safeGet(id,timeUrl, sexRe)
time = safeGet(id,timeUrl, timeRe)
这个代码如果断网的时候，调用了3次safeGet，每次调用都会往文本里面同一个id写多次httperror
251538 httperror
251538 httperror
251538 httperror
251538 httperror
多线程爬取信息？
数据统计可以用多线程，因为是独立的多个文本
1、Popen介绍
使用Popen可以自定义标准输入、标准输出和标准错误输出。我在SAP实习的时候，项目组在linux平台下经常使用Popen，可能是因为可以方便重定向输出。
下面这段代码借鉴了以前项目组的实现方法，Popen可以调用系统cmd命令。下面3个communicate()连在一起表示要等这3个线程都结束。
疑惑？
试验了一下，必须3个communicate()紧挨着才能保证3个线程同时开启，最后等待3个线程都结束。
p1=Popen(['python', 'ruisi.py', str(s0),str(s1)],bufsize=10000, stdout=subprocess.PIPE)
p2=Popen(['python', 'ruisi.py', str(s1),str(s2)],bufsize=10000, stdout=subprocess.PIPE)
p3=Popen(['python', 'ruisi.py', str(s2),str(s3)],bufsize=10000, stdout=subprocess.PIPE)
p1.communicate()
p2.communicate()
p3.communicate()
2、定义一个单线程的爬虫
用法：python ruisi.py <startNum> <endNum>
这段代码就是爬取[startNum, endNum)信息，输出到相应的文本里。它是一个单线程的程序，若要实现多线程的话，在外部调用它的地方实现多线程。
# ruisi.py
# coding=utf-8
import urllib2, re, sys, threading, time,thread
# myurl as 指定链接
# seWord as 正则表达式，用unicode表示
# 返回根据正则表达式匹配的信息或者None
def getInfo(myurl, seWord):
headers = {
'User-Agent': 'Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.6) Gecko/20091201 Firefox/3.5.6'
}
req = urllib2.Request(
url=myurl,
headers=headers
)
time.sleep(0.3)
response = urllib2.urlopen(req)
html = response.read()
html = unicode(html, 'utf-8')
timeMatch = seWord.search(html)
if timeMatch:
s = timeMatch.groups()
return s[0]
else:
return None
#尝试两次getInfo()
#第2次失败后，就把这个id标记为httperror
def safeGet(myid, myurl, seWord):
try:
return getInfo(myurl, seWord)
except:
try:
return getInfo(myurl, seWord)
except:
httperrorfile = open(file5, 'a')
info = '%d %sn' % (myid, 'httperror')
httperrorfile.write(info)
httperrorfile.close()
return 'httperror'
#输出一个 idArr 范围，比如[1,1001)
def searchWeb(idArr):
for id in idArr:
sexUrl = url1 % (id)
timeUrl = url2 % (id)
sex = safeGet(id,sexUrl, sexRe)
if not sex:
sex = safeGet(id,timeUrl, sexRe)
time = safeGet(id,timeUrl, timeRe)
if (sex is 'httperror') or (time is 'httperror') :
pass
else:
if sex:
info = '%d %s' % (id, sex)
if time:
info = '%s %sn' % (info, time)
wfile = open(file1, 'a')
wfile.write(info)
wfile.close()
else:
info = '%s %sn' % (info, 'notime')
errtimefile = open(file2, 'a')
errtimefile.write(info)
errtimefile.close()
else:
notexist = safeGet(id,sexUrl, notexistRe)
if notexist is 'httperror':
pass
else:
if notexist:
notexistfile = open(file3, 'a')
info = '%d %sn' % (id, 'notexist')
notexistfile.write(info)
notexistfile.close()
else:
unkownsexfile = open(file4, 'a')
info = '%d %sn' % (id, 'unkownsex')
unkownsexfile.write(info)
unkownsexfile.close()
def main():
reload(sys)
sys.setdefaultencoding('utf-8')
if len(sys.argv) != 3:
print 'usage: python ruisi.py <startNum> <endNum>'
sys.exit(-1)
global sexRe,timeRe,notexistRe,url1,url2,file1,file2,file3,file4,startNum,endNum,file5
startNum=int(sys.argv[1])
endNum=int(sys.argv[2])
sexRe = re.compile(u'em>u6027u522b</em>(.*?)</li')
timeRe = re.compile(u'em>u4e0au6b21u6d3bu52a8u65f6u95f4</em>(.*?)</li')
notexistRe = re.compile(u'(p>)u62b1u6b49uff0cu60a8u6307u5b9au7684u7528u6237u7a7au95f4u4e0du5b58u5728<')
url1 = 'http://rs.xidian.edu.cn/home.php?mod=space&uid=%s'
url2 = 'http://rs.xidian.edu.cn/home.php?mod=space&uid=%s&do=profile'
file1 = '..\newRuisi\correct%s-%s.txt' % (startNum, endNum)
file2 = '..\newRuisi\errTime%s-%s.txt' % (startNum, endNum)
file3 = '..\newRuisi\notexist%s-%s.txt' % (startNum, endNum)
file4 = '..\newRuisi\unkownsex%s-%s.txt' % (startNum, endNum)
file5 = '..\newRuisi\httperror%s-%s.txt' % (startNum, endNum)
searchWeb(xrange(startNum,endNum))
# numThread = 10
# searchWeb(xrange(endNum))
# total = 0
# for i in xrange(numThread):
# data = xrange(1+i,endNum,numThread)
# total =+ len(data)
# t=threading.Thread(target=searchWeb,args=(data,))
# t.start()
# print total
main()
多线程爬虫
代码
# coding=utf-8
from subprocess import Popen
import subprocess
import threading,time
startn = 1
endn = 300001
step =1000
total = (endn - startn + 1 ) /step
ISOTIMEFORMAT='%Y-%m-%d %X'
#hardcode 3 threads
#?]有深究3个线程好还是4或者更多个线程好
#输出格式化的年月日时分秒
#输出程序的耗时（以秒为单位）
for i in xrange(0,total,3):
startNumber = startn + step * i
startTime = time.clock()
s0 = startNumber
s1 = startNumber + step
s2 = startNumber + step*2
s3 = startNumber + step*3
p1=Popen(['python', 'ruisi.py', str(s0),str(s1)],bufsize=10000, stdout=subprocess.PIPE)
p2=Popen(['python', 'ruisi.py', str(s1),str(s2)],bufsize=10000, stdout=subprocess.PIPE)
p3=Popen(['python', 'ruisi.py', str(s2),str(s3)],bufsize=10000, stdout=subprocess.PIPE)
startftime ='[ '+ time.strftime( ISOTIMEFORMAT, time.localtime() ) + ' ] '
print startftime + '%s - %s download start... ' %(s0, s1)
print startftime + '%s - %s download start... ' %(s1, s2)
print startftime + '%s - %s download start... ' %(s2, s3)
p1.communicate()
p2.communicate()
p3.communicate()
endftime = '[ '+ time.strftime( ISOTIMEFORMAT, time.localtime() ) + ' ] '
print endftime + '%s - %s download end !!! ' %(s0, s1)
print endftime + '%s - %s download end !!! ' %(s1, s2)
print endftime + '%s - %s download end !!! ' %(s2, s3)
endTime = time.clock()
print "cost time " + str(endTime - startTime) + " s"
time.sleep(5)
这儿是记录时间戳的日志：
"D:Program FilesPython27python.exe" E:/pythonProject/webCrawler/sum.py
[ 2015-11-23 11:31:15 ] 1 - 1001 download start...
[ 2015-11-23 11:31:15 ] 1001 - 2001 download start...
[ 2015-11-23 11:31:15 ] 2001 - 3001 download start...
[ 2015-11-23 11:53:44 ] 1 - 1001 download end !!!
[ 2015-11-23 11:53:44 ] 1001 - 2001 download end !!!
[ 2015-11-23 11:53:44 ] 2001 - 3001 download end !!!
cost time 1348.99480677 s
[ 2015-11-23 11:53:50 ] 3001 - 4001 download start...
[ 2015-11-23 11:53:50 ] 4001 - 5001 download start...
[ 2015-11-23 11:53:50 ] 5001 - 6001 download start...
[ 2015-11-23 12:16:56 ] 3001 - 4001 download end !!!
[ 2015-11-23 12:16:56 ] 4001 - 5001 download end !!!
[ 2015-11-23 12:16:56 ] 5001 - 6001 download end !!!
cost time 1386.06407734 s
[ 2015-11-23 12:17:01 ] 6001 - 7001 download start...
[ 2015-11-23 12:17:01 ] 7001 - 8001 download start...
[ 2015-11-23 12:17:01 ] 8001 - 9001 download start...
上面是多线程的Log记录，从下面可以看出，1000个用户平均需要500s，一个id需要0.5s。500*300/3600 = 41.666666666667小时，大概需要两天的时间。
我们再试验一次单线程爬虫的耗时，记录如下:
"D:Program FilesPython27python.exe" E:/pythonProject/webCrawler/sum.py
1 - 1001 download start...
1 - 1001 download end !!!
cost time 1583.65911889 s
1001 - 2001 download start...
1001 - 2001 download end !!!
cost time 1342.46874278 s
2001 - 3001 download start...
2001 - 3001 download end !!!
cost time 1327.10885725 s
3001 - 4001 download start...
我们发现一次线程爬取1000个用户耗时的时间也需要1500s，而多线程程序是3*1000个用户耗时1500s。
故多线程确实能比单线程省很多时间。
Note:
在getInfo(myurl, seWord)里有time.sleep(0.3)这样一段代码，是为了防止批判访问BBS，而被BBS拒绝访问。这个0.3s对于上文多线程和单线程的统计时间有影响。
最后附上原始的，没有带时间戳的记录。（加上时间戳，可以知道程序什么时候开始爬虫的，以应对线程卡死情况。）
"D:Program FilesPython27python.exe" E:/pythonProject/webCrawler/sum.py
1 - 1001 download start...
1001 - 2001 download start...
2001 - 3001 download start...
1 - 1001 download end !!!
1001 - 2001 download end !!!
2001 - 3001 download end !!!
cost time 1532.74102812 s
3001 - 4001 download start...
4001 - 5001 download start...
5001 - 6001 download start...
3001 - 4001 download end !!!
4001 - 5001 download end !!!
5001 - 6001 download end !!!
cost time 2652.01624951 s
6001 - 7001 download start...
7001 - 8001 download start...
8001 - 9001 download start...
6001 - 7001 download end !!!
7001 - 8001 download end !!!
8001 - 9001 download end !!!
cost time 1880.61513696 s
9001 - 10001 download start...
10001 - 11001 download start...
11001 - 12001 download start...
9001 - 10001 download end !!!
10001 - 11001 download end !!!
11001 - 12001 download end !!!
cost time 1634.40575553 s
12001 - 13001 download start...
13001 - 14001 download start...
14001 - 15001 download start...
12001 - 13001 download end !!!
13001 - 14001 download end !!!
14001 - 15001 download end !!!
cost time 1403.62795496 s
15001 - 16001 download start...
16001 - 17001 download start...
17001 - 18001 download start...
15001 - 16001 download end !!!
16001 - 17001 download end !!!
17001 - 18001 download end !!!
cost time 1271.42177906 s
18001 - 19001 download start...
19001 - 20001 download start...
20001 - 21001 download start...
18001 - 19001 download end !!!
19001 - 20001 download end !!!
20001 - 21001 download end !!!
cost time 1476.04122024 s
21001 - 22001 download start...
22001 - 23001 download start...
23001 - 24001 download start...
21001 - 22001 download end !!!
22001 - 23001 download end !!!
23001 - 24001 download end !!!
cost time 1431.37074164 s
24001 - 25001 download start...
25001 - 26001 download start...
26001 - 27001 download start...
24001 - 25001 download end !!!
25001 - 26001 download end !!!
26001 - 27001 download end !!!
cost time 1411.45186874 s
27001 - 28001 download start...
28001 - 29001 download start...
29001 - 30001 download start...
27001 - 28001 download end !!!
28001 - 29001 download end !!!
29001 - 30001 download end !!!
cost time 1396.88837788 s
30001 - 31001 download start...
31001 - 32001 download start...
32001 - 33001 download start...
30001 - 31001 download end !!!
31001 - 32001 download end !!!
32001 - 33001 download end !!!
cost time 1389.01316718 s
33001 - 34001 download start...
34001 - 35001 download start...
35001 - 36001 download start...
33001 - 34001 download end !!!
34001 - 35001 download end !!!
35001 - 36001 download end !!!
cost time 1318.16040825 s
36001 - 37001 download start...
37001 - 38001 download start...
38001 - 39001 download start...
36001 - 37001 download end !!!
37001 - 38001 download end !!!
38001 - 39001 download end !!!
cost time 1362.59222822 s
39001 - 40001 download start...
40001 - 41001 download start...
41001 - 42001 download start...
39001 - 40001 download end !!!
40001 - 41001 download end !!!
41001 - 42001 download end !!!
cost time 1253.62498539 s
42001 - 43001 download start...
43001 - 44001 download start...
44001 - 45001 download start...
42001 - 43001 download end !!!
43001 - 44001 download end !!!
44001 - 45001 download end !!!
cost time 1313.50461988 s
45001 - 46001 download start...
46001 - 47001 download start...
47001 - 48001 download start...
45001 - 46001 download end !!!
46001 - 47001 download end !!!
47001 - 48001 download end !!!
cost time 1322.32317331 s
48001 - 49001 download start...
49001 - 50001 download start...
50001 - 51001 download start...
48001 - 49001 download end !!!
49001 - 50001 download end !!!
50001 - 51001 download end !!!
cost time 1381.58027296 s
51001 - 52001 download start...
52001 - 53001 download start...
53001 - 54001 download start...
51001 - 52001 download end !!!
52001 - 53001 download end !!!
53001 - 54001 download end !!!
cost time 1357.78699459 s
54001 - 55001 download start...
55001 - 56001 download start...
56001 - 57001 download start...
54001 - 55001 download end !!!
55001 - 56001 download end !!!
56001 - 57001 download end !!!
cost time 1359.76377246 s
57001 - 58001 download start...
58001 - 59001 download start...
59001 - 60001 download start...
57001 - 58001 download end !!!
58001 - 59001 download end !!!
59001 - 60001 download end !!!
cost time 1335.47829775 s
60001 - 61001 download start...
61001 - 62001 download start...
62001 - 63001 download start...
60001 - 61001 download end !!!
61001 - 62001 download end !!!
62001 - 63001 download end !!!
cost time 1354.82727645 s
63001 - 64001 download start...
64001 - 65001 download start...
65001 - 66001 download start...
63001 - 64001 download end !!!
64001 - 65001 download end !!!
65001 - 66001 download end !!!
cost time 1260.54731607 s
66001 - 67001 download start...
67001 - 68001 download start...
68001 - 69001 download start...
66001 - 67001 download end !!!
67001 - 68001 download end !!!
68001 - 69001 download end !!!
cost time 1363.58255686 s
69001 - 70001 download start...
70001 - 71001 download start...
71001 - 72001 download start...
69001 - 70001 download end !!!
70001 - 71001 download end !!!
71001 - 72001 download end !!!
cost time 1354.17163074 s
72001 - 73001 download start...
73001 - 74001 download start...
74001 - 75001 download start...
72001 - 73001 download end !!!
73001 - 74001 download end !!!
74001 - 75001 download end !!!
cost time 1335.00425259 s
75001 - 76001 download start...
76001 - 77001 download start...
77001 - 78001 download start...
75001 - 76001 download end !!!
76001 - 77001 download end !!!
77001 - 78001 download end !!!
cost time 1360.44054978 s
78001 - 79001 download start...
79001 - 80001 download start...
80001 - 81001 download start...
78001 - 79001 download end !!!
79001 - 80001 download end !!!
80001 - 81001 download end !!!
cost time 1369.72662457 s
81001 - 82001 download start...
82001 - 83001 download start...
83001 - 84001 download start...
81001 - 82001 download end !!!
82001 - 83001 download end !!!
83001 - 84001 download end !!!
cost time 1369.95550676 s
84001 - 85001 download start...
85001 - 86001 download start...
86001 - 87001 download start...
84001 - 85001 download end !!!
85001 - 86001 download end !!!
86001 - 87001 download end !!!
cost time 1482.53886433 s
87001 - 88001 download start...
88001 - 89001 download start...
89001 - 90001 download start...
以上就是关于python实现爬虫统计学校BBS男女比例的第二篇，重点介绍了多线程爬虫，希望对大家的学习有所帮助。
