根据官方手册执行composer global require "laravel/installer"
注意，"laravel/installer" 这里双引号不能少
显示Changed current directory to C:/Users/Administrator/AppData/Roaming/Composer
然后没反应了，因为去国外的镜像地址下载了。
应该先将composer换成国内镜像
composer config -g repo.packagist composer https://packagist.phpcomposer.com
https://blog.csdn.net/qq_37322178/article/details/85129652