PIP安装软件报错：“ERROR: Could not install packages due to an EnvironmentError: HTTPSConnectionPool(host=‘f

最近PIP安装软件总是报错，比如安装openpyxl，报错提示如下：

1.WARNING: Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ConnectTimeoutError(, 'Connection to files.pythonhosted.org timed out.

2.ERROR: Could not install packages due to an EnvironmentError: HTTPSConnectionPool(host=‘files.pythonhosted.org’, port=443): Max retries exceeded with url: /packages/91/d2/30ecd905746d1fee4004daae3f0051bf4b305bee1fe578bd7d1ea712d571/Pillow-7.2.0-cp38-cp38-win_amd64.whl (Caused by ConnectTimeoutError(, ‘Connection to files.pythonhosted.org timed out. (connect timeout=15)’))

以管理员身份运行cmd，cd至python scripts目录，我的安装在"D:Program FilesPython38scripts"

命令：pip install xxx
改为： pip install xxx -i http://pypi.douban.com/simple --trusted-host pypi.douban.com
xxx 为要安装的软件
例如：pip install openpyxl -i http://pypi.douban.com/simple --trusted-host pypi.douban.com

安装成功。