php -r "copy('https://install.phpcomposer.com/installer', 'composer-setup.php');" #下载安装脚本 － composer-setup.php － 到当前目录
php composer-setup.php #执行安装
php -r "unlink('composer-setup.php');" #删除安装脚本

composer install

mv composer.phar /usr/local/bin/composer
chmod 777 /usr/local/bin/composer

composer --version

composer config -g repos.packagist composer https://mirrors.cloud.tencent.com/composer/
或
composer config -g repo.packagist composer https://packagist.phpcomposer.com

composer update