CentOS 7.3 中安装 JDK 及环境变量配置

CentOS_7.3_x64

jdk-8u144-linux-x64

root

一、查看并卸载系统中的 jdk

[root@RemoteEshaon ~]# rpm -qa | grep java

javapackages-tools-3.4.1-6.el7_0.noarch
python-javapackages-3.4.1-6.el7_0.noarch
java-1.7.0-openjdk-1.7.0.75-2.5.4.2.el7_0.x86_64
tzdata-java-2015a-1.el7.noarch
java-1.7.0-openjdk-headless-1.7.0.75-2.5.4.2.el7_0.x86_64

[root@RemoteEshaon ~]# rpm -e --nodeps javapackages-tools-3.4.1-6.el7_0.noarch
[root@RemoteEshaon ~]# rpm -e --nodeps python-javapackages-3.4.1-6.el7_0.noarch
[root@RemoteEshaon ~]# rpm -e --nodeps tzdata-java-2015a-1.el7.noarch
[root@RemoteEshaon ~]# rpm -e --nodeps java-1.7.0-openjdk-headless-1.7.0.75-2.5.4.2.el7_0.x86_64

[root@RemoteEshaon ~]# rpm -qa | grep java[root@RemoteEshaon ~]#

二、安装 jdk

/usr

java

[root@RemoteEshaon ~]# mkdir /usr/java
[root@RemoteEshaon ~]# cd /usr/java

[root@RemoteEshaon ~]# cd /usr/java
[root@RemoteEshaon java]#  wget --no-cookies --no-check-certificate --header "Cookie: oraclelicense=accept-securebackup-cookie" http://download.oracle.com/otn-pub/java/jdk/8u144-b01/090f390dda5b47b9b721c7dfaa008135/jdk-8u144-linux-x64.rpm[/code] 
（3）安装 jdk，默认安装到当前路径 
/usr/java

[root@RemoteEshaon java]# sudo yum localinstall jdk-8u144-linux-x64.rpm

//...
//...
//...
Installed:
jdk-8u144-linux-x64.rpm 2000:1.8.0_102-fcs

Complete!
[root@RemoteEshaon java]#


（4）查看 jdk 安装目录

[root@RemoteEshaon java]# cd /usr/java
[root@RemoteEshaon java]# ls -lsah
total 12K
4.0K drwxr-xr-x   3 root root 4.0K Aug 31 15:32 .
4.0K drwxr-xr-x. 14 root root 4.0K Jul 22 13:15 ..
0 lrwxrwxrwx   1 root root   16 Aug 31 15:24 default -> /usr/java/latest
4.0K drwxr-xr-x   9 root root 4.0K Aug 31 15:24 jdk1.8.0_144
0 lrwxrwxrwx   1 root root   22 Aug 31 15:24 latest -> /usr/java/jdk1.8.0_144
[root@RemoteEshaon java]#


（5）在当前目录下 
/usr/java
 检验安装是否成功

[root@RemoteEshaon java]# java -version
java version "1.8.0_144"
Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)
[root@RemoteEshaon java]#


至此，安装成功！

（5）删除 RPM 文件

[root@RemoteEshaon java]# rm -rf jdk-8u144-linux-x64.rpm


三、在 root 用户下配置 JDK 环境变量
编辑环境变量配置文件：用Vim打开配置文件
/etc/profile，在文件末尾加入下面代码，保存并退出。

（1）切换目录，打开配置文件
/etc/profile

[root@RemoteEshaon java]# cd /etc/
[root@RemoteEshaon etc]# vim profile


（2）在文件末尾加入下面代码：

82 # User specific environment and startup programs
83     export JAVA_HOME=/usr/java/jdk1.8.0_144
84     export JRE_HOME=/usr/java/jdk1.8.0_144/jre
85     export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib:$CLASSPATH
86     export PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH


（3）使环境变量即时生效：

[root@RemoteEshaon etc]# source /etc/profile


（4）测试 jdk 环境是否配置成功

[root@RemoteEshaon etc]# cd
[root@RemoteEshaon ~]# java -version
java version "1.8.0_144"
Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)
[root@RemoteEshaon ~]#


至此，环境变量配置成功！

【参考】

[1] CentOS 7安装JDK

[2] How to install Oracle JDK 8 on CentOS

[3] LInux安装jdk的三种方法

[4] CentOS 7 配置Java环境变量

[5] 每天一个linux命令（23）：Linux 目录结构