这条命令查看你的镜像用的是那个地方的资源
composer config -g -l repo.packagist
于是换了国内的镜像
用cmd 输入以下命令
composer config -g repo.packagist composer https://packagist.phpcomposer.com
composer config -g repo.packagist composer https://mirrors.aliyun.com/composer/
原文:https://www.cnblogs.com/yaoliuyang/p/12815601.html