有关爬虫的问题

eavv

1. import urllib.request
   
2. import re
   
3. 
   
4. def open_url(url):
   
5.     req=urllib.request.Request(url)
   
6.     req.add_header('user-agent','Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36')
   
7.     page=urllib.request.urlopen(req)
   
8.     html=page.read().decode('utf-8')
   
9.     return html
   
10. def get_img(html):
    
11.     p=r'<img src="http://([^"]+\.jpg)'
    
12.     imagelist=re.findall(p,html)#应用findall方法中，如果给出的re有子组，那么就会把子组的内容单个返回回来
    
13.                                 #如果存在多个子组，将匹配的内容组合成元组 再返回
    
14. 
    
15.     for each in imagelist:
    
16.         print(each)
    
17.         # filename=each.split("/")[-1]
    
18.         # urllib.request.urlretrieve(each,filename,None)
    
19. 
    
20. 
    
21. 
    
22. 
    
23. if __name__=='__main__':
    
24.     url="http://tieba.baidu.com/p/2354064447#!/l/p1"
    
25.     get_img(open_url(url))

复制代码

是这样的，我这样运行的时候程序是可以打印出字符串的
然而，当我调用urllib.request.urlretrieve(each,filename,None)方法后（也就是打印语句下面的两行）后，它就报错
错误信息：
C:\Users\qx\AppData\Local\Programs\Python\Python35-32\python.exe "F:/work place/pycharm/爬虫/get_img.py"
Traceback (most recent call last):
  File "F:/work place/pycharm/爬虫/get_img.py", line 25, in <module>
    get_img(open_url(url))
  File "F:/work place/pycharm/爬虫/get_img.py", line 18, in get_img
    urllib.request.urlretrieve(each,filename,None)
  File "C:\Users\qx\AppData\Local\Programs\Python\Python35-32\lib\urllib\request.py", line 188, in urlretrieve
    with contextlib.closing(urlopen(url, data)) as fp:
  File "C:\Users\qx\AppData\Local\Programs\Python\Python35-32\lib\urllib\request.py", line 163, in urlopen
    return opener.open(url, data, timeout)
  File "C:\Users\qx\AppData\Local\Programs\Python\Python35-32\lib\urllib\request.py", line 451, in open
    req = Request(fullurl, data)
  File "C:\Users\qx\AppData\Local\Programs\Python\Python35-32\lib\urllib\request.py", line 269, in __init__
    self.full_url = url
  File "C:\Users\qx\AppData\Local\Programs\Python\Python35-32\lib\urllib\request.py", line 295, in full_url
    self._parse()
  File "C:\Users\qx\AppData\Local\Programs\Python\Python35-32\lib\urllib\request.py", line 324, in _parse
    raise ValueError("unknown url type: %r" % self.full_url)
ValueError: unknown url type: 'imgsrc.baidu.com/forum/pic/item/bede9735e5dde711c981db20a0efce1b9f1661d5.jpg'

Process finished with exit code 1