一、问题描述
当使用pip安装 jupyter notebook的时候出现问题，操作如下：
#在cmd中输入下面命令
pip install jupyter notebook结果报错如下：
如果需要复制内容可以在下面复制（和上面的图片内同相同）
(testpip) C:\Users\chang>pip install jupyter notebook
ERROR: Exception:
Traceback (most recent call last):
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\cli\base_command.py", line 173, in _main
status = self.run(options, args)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\cli\req_command.py", line 203, in wrapper
return func(self, options, args)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\commands\install.py", line 315, in run
requirement_set = resolver.resolve(
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\resolution\resolvelib\resolver.py", line 94, in resolve
result = self._result = resolver.resolve(
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 472, in resolve
state = resolution.resolve(requirements, max_rounds=max_rounds)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 341, in resolve
self._add_to_criteria(self.state.criteria, r, parent=None)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 172, in _add_to_criteria
if not criterion.candidates:
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\resolvelib\structs.py", line 151, in __bool__
return bool(self._sequence)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 140, in __bool__
return any(self)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 128, in <genexpr>
return (c for c in iterator if id(c) not in self._incompatible_ids)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 29, in _iter_built
for version, func in infos:
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\resolution\resolvelib\factory.py", line 272, in iter_index_candidate_infos
result = self._finder.find_best_candidate(
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\index\package_finder.py", line 851, in find_best_candidate
candidates = self.find_all_candidates(project_name)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\index\package_finder.py", line 798, in find_all_candidates
page_candidates = list(page_candidates_it)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\index\sources.py", line 134, in page_candidates
yield from self._candidates_from_page(self._link)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\index\package_finder.py", line 758, in process_project_url
html_page = self._link_collector.fetch_page(project_url)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\index\collector.py", line 490, in fetch_page
return _get_html_page(location, session=self.session)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\index\collector.py", line 400, in _get_html_page
resp = _get_html_response(url, session=session)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\index\collector.py", line 115, in _get_html_response
resp = session.get(
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\requests\sessions.py", line 555, in get
return self.request('GET', url, **kwargs)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_internal\network\session.py", line 454, in request
return super().request(method, url, *args, **kwargs)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\requests\sessions.py", line 542, in request
resp = self.send(prep, **send_kwargs)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\requests\sessions.py", line 655, in send
r = adapter.send(request, **kwargs)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\cachecontrol\adapter.py", line 53, in send
resp = super(CacheControlAdapter, self).send(request, **kw)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\requests\adapters.py", line 439, in send
resp = conn.urlopen(
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\urllib3\connectionpool.py", line 696, in urlopen
self._prepare_proxy(conn)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\urllib3\connectionpool.py", line 964, in _prepare_proxy
conn.connect()
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\urllib3\connection.py", line 359, in connect
conn = self._connect_tls_proxy(hostname, conn)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\urllib3\connection.py", line 500, in _connect_tls_proxy
return ssl_wrap_socket(
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\urllib3\util\ssl_.py", line 453, in ssl_wrap_socket
ssl_sock = _ssl_wrap_socket_impl(sock, context, tls_in_tls)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\site-packages\pip\_vendor\urllib3\util\ssl_.py", line 495, in _ssl_wrap_socket_impl
return ssl_context.wrap_socket(sock)
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\ssl.py", line 500, in wrap_socket
return self.sslsocket_class._create(
File "D:\01-install\20-anaconda\anaconda\envs\testpip\lib\ssl.py", line 997, in _create
raise ValueError("check_hostname requires server_hostname")
ValueError: check_hostname requires server_hostname二、问题分析
通过最后一句话（ValueError: check_hostname requires server_hostname）在网上的查找后找到原因。
由于网络代理（VPN）导致的问题。
三、问题解决
选择关掉VPN来解决问题。
