python - Python 中的 URL 错误

Question

我试图了解是否可以处理 python 中的以下错误。

所以我有一个程序重复调用以下行:

candidate = urllib2.urlopen(absolute_path)

运行程序几秒钟后，我关闭了 wifi 连接，并收到以下错误:

File "crawler.py", line 28, in urlQuery
  candidate = urllib2.urlopen(absolute_path)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 127, in urlopen
  return _opener.open(url, data, timeout)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 404, in open
  response = self._open(req, data)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 422, in _open
'_open', req)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 382, in _call_chain
  result = func(*args)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 1214, in http_open
  return self.do_open(httplib.HTTPConnection, req)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/urllib2.py", line 1184, in do_open
  raise URLError(err)
urllib2.URLError: <urlopen error [Errno 65] No route to host>

有什么办法可以处理这个错误吗？

Answer 1

取决于您收到此异常时想要执行的操作。您可以使用标准 Python 的异常处理技术 try-except。

try:
    candidate = urllib2.urlopen(absolute_path)
#except Exception as e: # catches any exception
except urllib2.URLError as e: # catches urllib2.URLError in e
    print ('WiFi connection perhaps lost !! Trying one more time...')
    try:
        candidate = urllib2.urlopen(absolute_path)
    except:
        print ('WiFi connection really lost !! Bailing out..')
        print (e) # print outs the exception message