这些错误是什么，我该如何处理？

Question

我正在使用这段简单的代码

for l in bios:
    OpenThisLink = url + l
    response = urllib2.urlopen(OpenThisLink)

来打开大约200个网址，并用正则表达式（和BeautifulSoup）进行搜索。但是在打开十几个网址后，我就遇到了这些错误，IDLE也自动退出了。这些错误是什么意思？我该如何处理它们呢？

谢谢。

Traceback (most recent call last):

  File "\PROJECTS\JD\jd10.py", line 15, in <module> response = urllib2.urlopen(OpenThisLink)

  File "C:\Python26\lib\urllib2.py", line 124, in urlopen return _opener.open(url, data, timeout)

  File "C:\Python26\lib\urllib2.py", line 389, in open response = meth(req, response)

  File "C:\Python26\lib\urllib2.py", line 502, in http_response 'http', request, response, code, msg, hdrs)

  File "C:\Python26\lib\urllib2.py", line 421, in error result = self._call_chain(*args)

  File "C:\Python26\lib\urllib2.py", line 361, in _call_chain result = func(*args)

  File "C:\Python26\lib\urllib2.py", line 597, in http_error_302 return self.parent.open(new)

  File "C:\Python26\lib\urllib2.py", line 389, in open response = meth(req, response)

  File "C:\Python26\lib\urllib2.py", line 502, in http_response 'http', request, response, code, msg, hdrs)

  File "C:\Python26\lib\urllib2.py", line 421, in error result = self._call_chain(*args)

  File "C:\Python26\lib\urllib2.py", line 361, in _call_chain result = func(*args)

  File "C:\Python26\lib\urllib2.py", line 597, in http_error_302 return self.parent.open(new)

  File "C:\Python26\lib\urllib2.py", line 389, in open response = meth(req, response)

  File "C:\Python26\lib\urllib2.py", line 502, in http_response 'http', request, response, code, msg, hdrs)

  File "C:\Python26\lib\urllib2.py", line 427, in error return self._call_chain(*args)

  File "C:\Python26\lib\urllib2.py", line 361, in _call_chain result = func(*args)

  File "C:\Python26\lib\urllib2.py", line 510, in http_error_default raise HTTPError(req.get_full_url(), code, msg, hdrs, fp) HTTPError: HTTP Error 404: Not Found

Answer 1

我对你使用的具体库不太了解。不过，从我看到的情况来看，这似乎是一个很长的错误追踪，最后指向了这个原始错误：

HTTP错误：HTTP错误404：未找到

我觉得其中有一个链接是坏的，这导致了一个异常（错误），但没有被处理。

补充一下：我说的“坏”是指服务器无法找到这个页面，所以才出现了404错误。

Answer 2

这里出现的错误是 HTTPError，具体来说，是因为你访问的某个网址返回了404错误。这意味着你请求的页面不存在。你可以选择忽略这个错误：

for l in bios:
    OpenThisLink = url + l
    try:
        response = urllib2.urlopen(OpenThisLink)
    except urllib2.HTTPError:
        pass

或者，你也可以重新抛出这个错误，并附上一个（稍微）更有意义的提示信息：

for l in bios:
    OpenThisLink = url + l
    try:
        response = urllib2.urlopen(OpenThisLink)
    except urllib2.HTTPError as e:
        raise Exception('Error opening %s: %s' % (e.geturl(), e))