1.查看java版本

[root@CFDB2 ~]# java -version
openjdk version "1.8.0_171"
OpenJDK Runtime Environment (build 1.8.0_171-b10)
OpenJDK 64-Bit Server VM (build 25.171-b10, mixed mode)

2.查看java安装软件

[root@CFDB2 ~]# rpm -qa|grep java
tzdata-java-2018e-3.el7.noarch
java-1.8.0-openjdk-1.8.0.171-8.b10.el7_5.x86_64
java-1.7.0-openjdk-headless-1.7.0.181-2.6.14.8.el7_5.x86_64
java-1.7.0-openjdk-1.7.0.181-2.6.14.8.el7_5.x86_64
javapackages-tools-3.4.1-11.el7.noarch
python-javapackages-3.4.1-11.el7.noarch
java-1.8.0-openjdk-headless-1.8.0.171-8.b10.el7_5.x86_64
[root@CFDB2 ~]#

3.卸载openjdk

.noarch可以不用删除

rpm -e --nodeps java-1.8.0-openjdk-headless-1.8.0.101-3.b13.el7_2.x86_64

4.上传jdk包

官网下载jdk包，上传到服务器上

5.解压

[root@localhost ruanjian]# tar -vzxf jdk-8u191-linux-x64.tar.gz

6.设置环境变量

[root@localhost ruanjian]# vim /etc/profile

末尾添加

#java_home
export JAVA_HOME=/ruanjian/jdk1.8.0_191
export PATH=$PATH:$JAVA_HOME/bin

保存退出，执行

[root@localhost ruanjian]# source /etc/profile

7.测试

[root@localhost ruanjian]# java -version
java version "1.8.0_191"
Java(TM) SE Runtime Environment (build 1.8.0_191-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)
[root@localhost ruanjian]#