一、备份
cd /etc/yum.repos.d/
mkdir bak
mv CentOS-Linux-* bak
二、下载新源
wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo
三、安装软件测试
sudo yum -y install java-11-openjdk-devel
java -version
sudo yum install git
git --version