//第一种方式：如下是修改composer.json文件来实现(在json配置的最后加上如下代码)
"repositories": {
"packagist": {
"type": "composer",
"url": "https://packagist.phpcomposer.com"
}
}//第二种方式：或者提前配置composer 默认使用国内镜像
composer config -g repo.packagist composer https://packagist.phpcomposer.com 