ubuntu20.04 中java的安装及环境配置

 

1、创建java安装目录

root@DESKTOP-1N42TVH:~# mkdir /usr/local/java
root@DESKTOP-1N42TVH:~# cd /usr/local/java/

 

2、下载jdk安装包，url：https://www.oracle.com/java/technologies/downloads/

 

 

root@DESKTOP-1N42TVH:/usr/local/java# wget https://download.oracle.com/otn/java/jdk/8u331-b09/165374ff4ea84ef0bbd821706e29b123/jdk-8u331-linux-x64.tar.gz

 

3、解压安装包

root@DESKTOP-1N42TVH:/usr/local/java# tar -xzvf jdk-8u331-linux-x64.tar.gz
root@DESKTOP-1N42TVH:/usr/local/java# mv jdk-8u331-linux-x64.tar.gz jdk1.8.0_331/
root@DESKTOP-1N42TVH:/usr/local/java# cd jdk1.8.0_331/

 

4、配置系统环境变量，编辑/etc/profile文件，在文件的末尾添加一下信息，保存退出：

root@DESKTOP-1N42TVH:/usr/local/java/jdk1.8.0_331# vim /etc/profile
#java env
export JAVA_HOME=/usr/local/java/jdk1.8.0_331
export JRE_HOME=$JAVA_HOME/jre
export CLASSPATH=.:$CLASSPATH:$JAVA_HOME/lib:$JRE_HOME/lib
export PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin
~
~
~
:wq!

 

 

6、使用source /etc/profile命令使刚才配置的生效

root@DESKTOP-1N42TVH:/usr/local/java/jdk1.8.0_331# source /etc/profile

 

7、测试配置效果

root@DESKTOP-1N42TVH:/usr/local/java/jdk1.8.0_331# java -version
java version "1.8.0_331"
Java(TM) SE Runtime Environment (build 1.8.0_331-b09)
Java HotSpot(TM) 64-Bit Server VM (build 25.331-b09, mixed mode)
root@DESKTOP-1N42TVH:/usr/local/java/jdk1.8.0_331# javac -version
javac 1.8.0_331
root@DESKTOP-1N42TVH:/usr/local/java/jdk1.8.0_331# echo $JAVA_HOME
/usr/local/java/jdk1.8.0_331
root@DESKTOP-1N42TVH:/usr/local/java/jdk1.8.0_331# echo $JRE_HOME
/usr/local/java/jdk1.8.0_331/jre
root@DESKTOP-1N42TVH:/usr/local/java/jdk1.8.0_331# echo $CLASSPATH
.::/usr/local/java/jdk1.8.0_331/lib:/usr/local/java/jdk1.8.0_331/jre/lib