JSONDecodeError: Expecting value: line 1 column 1 (char 0)

JSONDecodeError                           Traceback (most recent call last)<ipython-input-8-c6de33151325> in <module>()     11 url_visit='http://kuaidi100.com/query?type=shentong&postid={}'.format(postid)     12 crawl_content=urlrequest.urlopen(url_visit).read()---> 13 json_content=json.loads(crawl_content.decode("utf8"))     14 i=0     15 for i in 10:~\AppData\Local\conda\conda\envs\course_py35\lib\json\__init__.py in loads(s, encoding, cls, object_hook, parse_float, parse_int, parse_constant, object_pairs_hook, **kw)    317             parse_int is None and parse_float is None and    318             parse_constant is None and object_pairs_hook is None and not kw):--> 319         return _default_decoder.decode(s)    320     if cls is None:    321         cls = JSONDecoder~\AppData\Local\conda\conda\envs\course_py35\lib\json\decoder.py in decode(self, s, _w)    337     338         """--> 339         obj, end = self.raw_decode(s, idx=_w(s, 0).end())    340         end = _w(s, end).end()    341         if end != len(s):~\AppData\Local\conda\conda\envs\course_py35\lib\json\decoder.py in raw_decode(self, s, idx)    355             obj, end = self.scan_once(s, idx)    356         except StopIteration as err:--> 357             raise JSONDecodeError("Expecting value", s, err.value) from None    358         return obj, endJSONDecodeError: Expecting value: line 1 column 1 (char 0)
原因 ， url_visit='http://www.kuaidi100.com/query?type=shentong&postid={}'.format(postid)  我少些了WWW
先去把网址看一下是否可用再说