Linux 安装Jdk环境

Linux 安装Jdk环境

jdk下载地址：https://www.oracle.com/technetwork/java/javase/archive-139210.html

1.检查Linux系统是否安装有jdk

[root@kk download]# java -version
openjdk version "1.8.0_232"
OpenJDK Runtime Environment (build 1.8.0_232-b09)
OpenJDK 64-Bit Server VM (build 25.232-b09, mixed mode)

2.查找Linux系统中的java文件

[root@kk download]# rpm -qa | grep java
python-javapackages-3.4.1-11.el7.noarch
java-1.8.0-openjdk-1.8.0.232.b09-0.el7_7.x86_64
javapackages-tools-3.4.1-11.el7.noarch
java-1.8.0-openjdk-headless-1.8.0.232.b09-0.el7_7.x86_64
java-1.8.0-openjdk-headless-debug-1.8.0.232.b09-0.el7_7.x86_64
java-1.8.0-openjdk-devel-debug-1.8.0.232.b09-0.el7_7.x86_64
tzdata-java-2019c-1.el7.noarch
java-1.8.0-openjdk-debug-1.8.0.232.b09-0.el7_7.x86_64

3.卸载系统自带的jdk，检查卸载效果

[root@kk download]# rpm -e --nodeps java-1.8.0-openjdk-1.8.0.232.b09-0.el7_7.x86_64
[root@kk download]# rpm -e --nodeps javapackages-tools-3.4.1-11.el7.noarch
[root@kk download]# rpm -e --nodeps java-1.8.0-openjdk-headless-1.8.0.232.b09-0.el7_7.x86_64
[root@kk download]# rpm -e --nodeps java-1.8.0-openjdk-headless-debug-1.8.0.232.b09-0.el7_7.x86_64
[root@kk download]# rpm -e --nodeps java-1.8.0-openjdk-devel-debug-1.8.0.232.b09-0.el7_7.x86_64
[root@kk download]# rpm -e --nodeps java-1.8.0-openjdk-debug-1.8.0.232.b09-0.el7_7.x86_64

yan 证

[root@kk download]# rpm -qa |grep java
python-javapackages-3.4.1-11.el7.noarch
tzdata-java-2019c-1.el7.noarch

4.解压jdk，进入java目录查看解压效果

cd /usr/local/java
# 解压JDK压缩包
tar -zxvf jdk-8u181-linux-x64.tar.gz
# 解压完成后，删除压缩包
rm -f jdk-8u181-linux-x64.tar.gz

5.配置java环境变量，刷新配置

获取jdk安装的绝对路径，作为标识JAVA_HOME
获取jre安装的绝对路径，作为标识JRE_HOME

打开环境变量配置文件：

vi /etc/profile

具体配置：

JAVA_HOME=/usr/local/java/jdk1.8.0_221
JRE_HOME=/usr/local/java/jdk1.8.0_221/jre
CLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin
export JAVA_HOME JRE_HOME CLASS_PATH PATH

刷新环境变量：

[root@kk opt]# source /etc/profile

6.检查java安装效果

[root@kk opt]# java -version
java version "1.8.0_221"
Java(TM) SE Runtime Environment (build 1.8.0_221-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.221-b11, mixed mode)