01.import socket 
02.import time 
03.timeout = 20  
04.socket.setdefaulttimeout(timeout)#这里对整个socket层设置超时时间。后续文件中如果再使用到socket，不必再设置  
05.sleep_download_time = 10 
06.time.sleep(sleep_download_time) #这里时间自己设定  
07.request = urllib.request.urlopen(url)#这里是要读取内容的url  
08.content = request.read()#读取，一般会在这里报异常  
09.request.close()#记得要关闭 

try: 
  time.sleep(self.sleep_download_time) 
  request = urllib.request.urlopen(url) 
  content = request.read() 
  request.close() 
   
except UnicodeDecodeError as e: 
     
  print('-----UnicodeDecodeError url:',url) 
   
except urllib.error.URLError as e: 
  print("-----urlError url:",url) 
 
except socket.timeout as e: 
  print("-----socket timout:",url) 

def Download_auto(downloadlist,fun,sleep_time=15): 
  while True:     
    try: # 外包一层try  
      value = fun(downloadlist,sleep_time) # 这里的fun是你的下载函数，我当函数指针传进来。 
      # 只有正常执行方能退出。  
      if value == Util.SUCCESS: 
        break 
    except : # 如果发生了10054或者IOError或者XXXError 
      sleep_time += 5 #多睡5秒，重新执行以上的download.因为做了检查点的缘故，上面的程序会从抛出异常的地方继续执行。防止了因为网络连接不稳定带来的程序中断。 
      print('enlarge sleep time:',sleep_time) 

# 打印下载信息  
def reporthook(blocks_read, block_size, total_size): 
  if not blocks_read: 
    print ('Connection opened') 
  if total_size < 0: 
    print ('Read %d blocks' % blocks_read) 
  else: 
    # 如果找不到，页面不存在，可能totalsize就是0，不能计算百分比  
    print('downloading:%d MB, totalsize:%d MB' % (blocks_read*block_size/1048576.0,total_size/1048576.0)) 
    
 
def Download(path,url): 
#url = 'http://downloads.sourceforge.net/sourceforge/alliancep2p/Alliance-v1.0.6.jar' 
  #filename = url.rsplit("/")[-1]  
  try: 
  # python自带的下载函数  
    urllib.request.urlretrieve(url, path, reporthook) 
  except IOError as e: # 如果找不到，好像会引发IOError。 
    print("download ",url,"/nerror:",e) 
  print("Done:%s/nCopy to:%s" %(url,path))