安装jdk

yum install -y java-1.8.0-openjdk.x86_64

默认安装到usr/lib/jvm目录下

查看JDK信息，输入命令：java -version
检测JDK安装包，输入命令：rpm -qa | grep java

进入安装目录。

输入命令：cd /usr/lib/jvm

删除Java相关文件，输入命令：rm -rf /usr/lib/jvm 

配置环境

输入命令：vim /etc/profile

#java environment
export JAVA_HOME=/home/jdk/jdk1.8.0_261
export CLASSPATH=.:${JAVA_HOME}/jre/lib/rt.jar:${JAVA_HOME}/lib/dt.jar:${JAVA_HOME}/lib/tools.jar
export PATH=$PATH:${JAVA_HOME}/bin#java environment
export JAVA_HOME=/home/jdk/jdk1.8.0_261
export CLASSPATH=$:CLASSPATH:$JAVA_HOME/lib/
export PATH=$PATH:$JAVA_HOME/bin#java environment
export JAVA_HOME=/home/jdk/jdk1.8.0_261
export JRE_HOME=${JAVA_HOME}/jre  
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib  
export PATH=${JAVA_HOME}/bin:$PATH

输入命令：s