yum install 下载后保存rpm包

keepcache=0 更改为1下载RPM包 不会自动删除

vi /etc/yum.conf 

[main]
cachedir=/var/cache/yum/$basearch/$releasever # 安装包默认下载地址
keepcache=1 # 不会自动删除
debuglevel=2
logfile=/var/log/yum.log
exactarch=1
obsoletes=1
gpgcheck=1
plugins=1
installonly_limit=5
bugtracker_url=http://bugs.centos.org/set_project.php?project_id=23&ref=http://bugs.centos.org/bug_report_page.php?category=yum
distroverpkg=centos-release

只下载安装包，不安装指令

yum install --downloadonly --downloaddir=/home/java java