1. wget直接下载composer.phar直接下载composer.phar部署目录：(版本下载地址获取)
wget 'https://getcomposer.org/download/1.8.5/composer.phar'
2.将composer部署到全局
mv composer.phar /usr/local/bin/composer
3.设置权限
sudo chmod XXX /usr/local/bin/composer
4.若php安装位置不在/usr/local/bin/,则设置软连接
sudo ln /usr/local/php/bin/php /usr/local/bin/php
5.修改为阿里云镜像
composer config -g repo.packagist composer https://mirrors.aliyun.com/composer/
6.windows下载composer
https://developer.aliyun.com/article/1076259
