Python pip Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available.")

 Windows 10， Python 3.8

pip install opencv-python

Could not fetch URL https://pypi.org/simple/pip/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.org', port=443): Max retries exceeded with url: /simple/pip/ (Caused by SSLError("Can't connect to HTTPS URL because the SSL module is not available."))

解决办法
 
前往下面地址，下载和安装OpenSSL：
    https://slproweb.com/products/Win32OpenSSL.html

下载对应自己系统的OpenSSL的EXE安装包，选择的是 Win64 OpenSSL v1.1.1n （下载文件链接  https://slproweb.com/download/Win64OpenSSL-1_1_1n.exe ），安装之后就可以正常使用了（安装在默认路径C盘）。采用迅雷下载比较快。

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安装 cv2

E:\Eprogramfiles\Anaconda3\Scripts>python
Python 3.8.10 (tags/v3.8.10:3d8993a, May  3 2021, 11:48:03) [MSC v.1928 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()

E:\Eprogramfiles\Anaconda3\Scripts>pip install opencv-python -i https://pypi.mirrors.ustc.edu.cn/simple/