JDK安装

一.下载安转包

https://www.oracle.com/java/technologies/javase/javase-jdk8-downloads.html

二. 解压  

 shell>tar -zxvf jdk-8u291-linux-x64.tar.gz

三.配置环境变量  

        vi /etc/profile  

添加内容：

        export JAVA_HOME=/usr/local/jdk1.8.0_291

        export PATH=$PATH:$JAVA_HOME/bin

        export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar