以下操作都是在阿里云服务器上进行，默认yum源就是阿里云的。如果默认不是阿里云或者163的，建议修改之后再进行yum操作。修改yum源为阿里源
检查是否已经安装
rpm -qa | grep java
rpm -qa | grep jdk
rpm -qa | grep gcj没有输出则代表没有安装
查看是否检索包含Java1.8的列表
[root@Spider1 ~]# yum list java-1.8*
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Available Packages
java-1.8.0-openjdk.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk.x86_64 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-accessibility.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-accessibility.x86_64 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-accessibility-debug.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-accessibility-debug.x86_64 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-debug.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-debug.x86_64 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-demo.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-demo.x86_64 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-demo-debug.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-demo-debug.x86_64 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-devel.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-devel.x86_64 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-devel-debug.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-devel-debug.x86_64 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-headless.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-headless.x86_64 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-headless-debug.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-headless-debug.x86_64 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-javadoc.noarch 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-javadoc-debug.noarch 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-javadoc-zip.noarch 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-javadoc-zip-debug.noarch 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-src.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-src.x86_64 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-src-debug.i686 1:1.8.0.181-3.b13.el7_5 updates
java-1.8.0-openjdk-src-debug.x86_64 1:1.8.0.181-3.b13.el7_5 updates安装Java1.8下的所有文件
yum install java-1.8.0-openjdk* -y验证
此种安装方式省去了环境变量配置的环节
[root@Spider1 ~]# java -version
openjdk version "1.8.0_181"
OpenJDK Runtime Environment (build 1.8.0_181-b13)
OpenJDK 64-Bit Server VM (build 25.181-b13, mixed mode)
[root@Spider1 ~]# jps
3721 Jps
[root@Spider1 ~]# javac
Usage: javac <options> <source files>
where possible options include:
-g Generate all debugging info
-g:none Generate no debugging info
......略可以发现，在没有手动配置环境变量的前提下，jps、javac等命令能够正常执行。