composer config -g repo.packagist composer https://mirrors.aliyun.com/composer/
//以上为全局配置
composer config -g --unset repos.packagist
//以上为取消配置
删除已经安装过的包
composer remove vendor/package
composer update
原文：https://www.cnblogs.com/zhaoxizhe/p/11832284.html