WARNING: The repository located at pypi.douban.com is not a trusted or secure host and is being ignored. If this repository is available via HTTPS we recommend you use HTTPS instead, otherwise you may silence this warning and allow it anyway with '--trusted-host pypi.douban.com'.
解决方式:
文件则加上 trusted-host=镜像站域名
临时则加上 --trusted-host 域名