查看centOS上自带jdk版本
[root@localhost ~]# rpm -qa |grep java
tzdata-java-2021a-1.el7.noarch
python-javapackages-3.4.1-11.el7.noarch
java-1.8.0-openjdk-headless-1.8.0.292.b10-1.el7_9.x86_64
javapackages-tools-3.4.1-11.el7.noarch
java-1.8.0-openjdk-1.8.0.292.b10-1.el7_9.x86_64
java-1.8.0-openjdk-devel-1.8.0.292.b10-1.el7_9.x86_64
卸载
rpm -e --nodeps java-1.8.0-openjdk-devel-1.8.0.292.b10-1.el7_9.x86_64
xxx
或者全部
rpm -qa | grep java | xargs rpm -e --nodeps
下载
JDK下载地址 选择版本登录下载，本次安装下载8u271
解压
[root@localhost home]# tar -zxvf jdk-8u271-linux-x64.tar.gz
xxx
jdk1.8.0_271/src.zip
jdk1.8.0_271/THIRDPARTYLICENSEREADME-JAVAFX.txt
jdk1.8.0_271/javafx-src.zip
jdk1.8.0_271/jmc.txt
移动到 /usr/local
[root@localhost home]# mv jdk1.8.0_271 /usr/local/
配置环境变量
[root@localhost home]# vim /etc/profile
#在末尾添加
#java environment
#注意jdk实际安装路径
export JAVA_HOME=/usr/local/jdk1.8.0_271
export CLASSPATH=.:$JAVA_HOME/jre/lib/rt.jar:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export PATH=$PATH:$JAVA_HOME/bin
使配置生效
[root@localhost home]# source /etc/profile
检查是否安装成功
[root@localhost home]# java -version
java version "1.8.0_271"
Java(TM) SE Runtime Environment (build 1.8.0_271-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.271-b09, mixed mode)
至此表示安装OK
