Python3多线程爬虫实例讲解代码

# coding=utf-8
import threading, queue, time, urllib
from urllib import request
baseUrl = 'http://www.pythontab.com/html/pythonjichu/'
urlQueue = queue.Queue()
for i in range(2, 10):
 url = baseUrl + str(i) + '.html'
 urlQueue.put(url)
 #print(url)
def fetchUrl(urlQueue):
 while True:
  try:
   #不阻塞的读取队列数据
   url = urlQueue.get_nowait()
   i = urlQueue.qsize()
  except Exception as e:
   break
  print ('Current Thread Name %s, Url: %s ' % (threading.currentThread().name, url))
  try:
   response = urllib.request.urlopen(url)
   responseCode = response.getcode()
  except Exception as e:
   continue
  if responseCode == 200:
   #抓取内容的数据处理可以放到这里
   #为了突出效果， 设置延时
   time.sleep(1)
if __name__ == '__main__':
 startTime = time.time()
 threads = []
 # 可以调节线程数， 进而控制抓取速度
 threadNum = 4
 for i in range(0, threadNum):
  t = threading.Thread(target=fetchUrl, args=(urlQueue,))
  threads.append(t)
 for t in threads:
  t.start()
 for t in threads:
  #多线程多join的情况下，依次执行各线程的join方法, 这样可以确保主线程最后退出， 且各个线程间没有阻塞
  t.join()
 endTime = time.time()
 print ('Done, Time cost: %s ' % (endTime - startTime))

Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/2.html 
Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/3.html 
Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/4.html 
Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/5.html 
Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/6.html 
Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/7.html 
Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/8.html 
Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/9.html 
Done, Time cost: 8.182249069213867

Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/2.html 
Current Thread Name Thread-2, Url: http://www.pythontab.com/html/pythonjichu/3.html 
Current Thread Name Thread-2, Url: http://www.pythontab.com/html/pythonjichu/4.html 
Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/5.html 
Current Thread Name Thread-2, Url: http://www.pythontab.com/html/pythonjichu/6.html 
Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/7.html 
Current Thread Name Thread-2, Url: http://www.pythontab.com/html/pythonjichu/8.html 
Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/9.html 
Done, Time cost: 4.0987958908081055

Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/2.html 
Current Thread Name Thread-2, Url: http://www.pythontab.com/html/pythonjichu/3.html 
Current Thread Name Thread-3, Url: http://www.pythontab.com/html/pythonjichu/4.html 
Current Thread Name Thread-4, Url: http://www.pythontab.com/html/pythonjichu/5.html 
Current Thread Name Thread-2, Url: http://www.pythontab.com/html/pythonjichu/6.html 
Current Thread Name Thread-4, Url: http://www.pythontab.com/html/pythonjichu/7.html 
Current Thread Name Thread-1, Url: http://www.pythontab.com/html/pythonjichu/9.html 
Current Thread Name Thread-3, Url: http://www.pythontab.com/html/pythonjichu/8.html 
Done, Time cost: 2.287320137023926