composer Changed current directory to没反应
根据官方手册执行composer global require "laravel/installer"
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