Linux安装JDK，配置环境变量

系统：Ubuntu 18.04

JDK：JDK 1.8

一、下载JDK

下载地址：https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

点击下载,弹出登录页面  登录/注册  即可

二、将jdk传至linux云服务器

1.创建目录

sudo mkdir /usr/lib/jdk

2.使用Xshell 6 软件将jdk上传到新建的目录下

三、安装

1.解压缩

tar -zxvf jdk-8u211-linux-x64.tar.gz -C /usr/lib/jdk/

2.修改环境变量

sudo vim ~/.bashrc

文件末尾追加下面内容

#set oracle jdk environment
export JAVA_HOME=/usr/lib/jvm/jdk1.7.0_60  ## 这里要注意目录要换成自己解压的jdk 目录
export JRE_HOME=${JAVA_HOME}/jre  
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib  
export PATH=${JAVA_HOME}/bin:$PATH  

使环境变量马上生效

source ~/.bashrc

3.设置系统默认jdk 版本

sudo update-alternatives --install /usr/bin/java java /usr/lib/jdk/jdk1.8.0_211/bin/java 300
sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jdk/jdk1.8.0_211/bin/javac 300
sudo update-alternatives --install /usr/bin/jar jar /usr/lib/jdk/jdk1.8.0_211/bin/jar 300
sudo update-alternatives --install /usr/bin/javah javah /usr/lib/jdk/jdk1.8.0_211/bin/javah 300
sudo update-alternatives --install /usr/bin/javap javap /usr/lib/jdk/jdk1.8.0_211/bin/javap 300

然后执行:

sudo update-alternatives --config java
sudo update-alternatives --config javac

若是初次安装jdk,会有下面的提示     

   There is only one alternative in link group java (providing /usr/bin/java): 
    /usr/lib/jvm/jdk1.7.0_60/bin/java

4.测试jdk是否安装成功

java -version

java version "1.8.0_211"
Java(TM) SE Runtime Environment (build 1.8.0_211-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.211-b12, mixed mode)


javac -version

Java(TM) SE Runtime Environment (build 1.8.0_211-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.211-b12, mixed mode)
root@myHost:/usr/lib/jdk# javac -version
javac 1.8.0_211

 

jdk安装成功...