概述：pycharm中想引用requests庫，失敗 ，遇到的3個大問題及解決方案如下：
（一）問題1：命令窗口中安裝requests --- pip install requests 失敗
提示：Requirement already satisfied （原因：因為和已存在的requests庫沖突導致）
C:\Users\Administrator>pip install requests
Requirement already satisfied: requests in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (2.27.1)
Requirement already satisfied: idna<4,>=2.5 in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (from requests) (3.3)
Requirement already satisfied: charset-normalizer~=2.0.0 in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (from requests) (2.0.10)
Requirement already satisfied: certifi>=2017.4.17 in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (from requests) (2021.10.8)
Requirement already satisfied: urllib3<1.27,>=1.21.1 in c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages (from requests) (1.26.8
【解法1】：pip install --target [指定路徑] [指定包]
pip install --target c:\users\administrator\appdata\local\programs\python\python310\lib\site-packages requests
（二）問題2：使用指定路徑安裝requests仍提示錯誤：ValueError: check_hostname requires server_hostname （原因：打開了fiddler使用代理導致）
【解法2】：
關掉fiddler后問題解決！但是，又提示warning You should consider upgrading via the 'C:\Users\Administrator\AppData\Local\Programs\Python\Python310\python.exe -m pip install --upgrade pip' command.
執行 C:\Users\Administrator\AppData\Local\Programs\Python\Python310\python.exe -m pip install --upgrade pip' command 后成功！
（三）問題3：安裝requests成功，但是在pycharm中仍無法引用
【解法3】：在pycharm里面直接下載安裝需要的庫
File->settings->projetct->Python Interpreter 點擊“+”，在Available Packages頁面，搜索 requests -->Install Package
終於 成功引用！！
