下载安装JDK

##下载jdk
yum install java-1.8.0-openjdk.x86_64
Install  1 Package (+64 Dependent packages)

Total download size: 46 M
Installed size: 153 M
Is this ok [y/d/N]: y
...
..
.
Complete!
##看到以上则安装成功

配置环境变量

通过 yum 方式安装 jdk 的软件默认路径为： /usr/lib/jvm

[root@lavm-kixcjxxx ~]# ls -l /usr/lib/jvm
total 4
drwxr-xr-x 3 root root 4096 Jan 12 01:22 java-1.8.0-openjdk-1.8.0.392.b08-2.el7_9.x86_64
lrwxrwxrwx 1 root root   21 Jan 12 01:22 jre -> /etc/alternatives/jre
lrwxrwxrwx 1 root root   27 Jan 12 01:22 jre-1.8.0 -> /etc/alternatives/jre_1.8.0
lrwxrwxrwx 1 root root   35 Jan 12 01:22 jre-1.8.0-openjdk -> /etc/alternatives/jre_1.8.0_openjdk
lrwxrwxrwx 1 root root   51 Jan 12 01:22 jre-1.8.0-openjdk-1.8.0.392.b08-2.el7_9.x86_64 -> java-1.8.0-openjdk-1.8.0.392.b08-2.el7_9.x86_64/jre
lrwxrwxrwx 1 root root   29 Jan 12 01:22 jre-openjdk -> /etc/alternatives/jre_openjdk


## vim打开并且编辑文件
vim ~/.bashrc

##最后一行追加JAVA配置
# 设置Java环境变量
JAVA_HOME=/usr/lib/jvm/jre-1.6.0-openjdk.x86_64
PATH=$PATH:$JAVA_HOME/bin
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export JAVA_HOME CLASSPATH PATH

##保存并退出
ESC -> :wq!

##使配置文件生效
source ~/.bashrc

验证安装成功

[root@lavm-xxxxxxx /]# java -version
openjdk version "1.8.0_392"
OpenJDK Runtime Environment (build 1.8.0_392-b08)
OpenJDK 64-Bit Server VM (build 25.392-b08, mixed mode)