CentOS 7系统中JDK的安装与配置

操作系统版本：CentOS Linux release 7.2.1511 (Core)

JDK版本：jdk-8u111-nb-8_2-linux-x64.sh

安装方式：Shell脚本安装

下载地址：http://www.oracle.com/technetwork/java/javase/downloads/index.html

安装准备：

（1）查看系统已安装JDK版本（已安装JDK版本为OpenJDK）：

[[email protected] ~]# java -version
openjdk version "1.8.0_65"
OpenJDK Runtime Environment (build 1.8.0_65-b17)
OpenJDK 64-Bit Server VM (build 25.65-b01, mixed mode)

（2）查看已安装JDK详细信息：

[[email protected] ~]# rpm -qa | grep java
java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64
tzdata-java-2015g-1.el7.noarch
python-javapackages-3.4.1-11.el7.noarch
javapackages-tools-3.4.1-11.el7.noarch

java-1.7.0-openjdk-headless-1.7.0.91-2.6.2.3.el7.x86_64
java-1.7.0-openjdk-1.7.0.91-2.6.2.3.el7.x86_64
java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64

（3）卸载已安装的OpenJDK：

[[email protected] ~]# rpm -e --nodeps tzdata-java-2015g-1.el7.noarch
[[email protected] ~]# rpm -e --nodeps java-1.7.0-openjdk-headless-1.7.0.91-2.6.2.3.el7.x86_64
[[email protected] ~]# rpm -e --nodeps java-1.7.0-openjdk-1.7.0.91-2.6.2.3.el7.x86_64
[[email protected] ~]# rpm -e --nodeps java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64
[[email protected] ~]# rpm -e --nodeps java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64

安装步骤：

（1）在Windows系统中从上述网站下载最新版JDK 64位版本。

（2）用WinSCP工具将下载的JDK文件传入虚拟机中CentOS系统的/usr/local文件夹下。

（3）进入/usr/local文件夹，查看jdk-8u111-nb-8_2-linux-x64.sh脚本的执行权限：

[[email protected] ~]# cd /usr/local
[[email protected] local]# ls
bin  games    jdk-8u111-nb-8_2-linux-x64.sh  lib64    sbin   src
etc  include  lib                            libexec  share
[[email protected] local]# ls -l
total 289396
drwxr-xr-x. 2 root root      4096 Aug 12  2015 bin
drwxr-xr-x. 2 root root      4096 Aug 12  2015 etc
drwxr-xr-x. 2 root root      4096 Aug 12  2015 games
drwxr-xr-x. 2 root root      4096 Aug 12  2015 include
-rw-r--r--. 1 root root 296300544 Nov  7 16:29 jdk-8u111-nb-8_2-linux-x64.sh
drwxr-xr-x. 2 root root      4096 Aug 12  2015 lib
drwxr-xr-x. 2 root root      4096 Aug 12  2015 lib64
drwxr-xr-x. 2 root root      4096 Aug 12  2015 libexec
drwxr-xr-x. 2 root root      4096 Aug 12  2015 sbin

drwxr-xr-x. 5 root root      4096 Nov  6 14:01 share
drwxr-xr-x. 2 root root      4096 Aug 12  2015 src

（4）增加root用户对 jdk-8u111-nb-8_2-linux-x64.sh文件的执行权限：

[[email protected] local]# chmod u+x jdk-8u111-nb-8_2-linux-x64.sh 
[[email protected] local]# ls -l
total 289396
drwxr-xr-x. 2 root root      4096 Aug 12  2015 bin
drwxr-xr-x. 2 root root      4096 Aug 12  2015 etc
drwxr-xr-x. 2 root root      4096 Aug 12  2015 games
drwxr-xr-x. 2 root root      4096 Aug 12  2015 include
-rwxr--r--. 1 root root 296300544 Nov  7 16:29 jdk-8u111-nb-8_2-linux-x64.sh

drwxr-xr-x. 2 root root      4096 Aug 12  2015 lib
drwxr-xr-x. 2 root root      4096 Aug 12  2015 lib64
drwxr-xr-x. 2 root root      4096 Aug 12  2015 libexec
drwxr-xr-x. 2 root root      4096 Aug 12  2015 sbin
drwxr-xr-x. 5 root root      4096 Nov  6 14:01 share
drwxr-xr-x. 2 root root      4096 Aug 12  2015 src

（5）运行该JDK shell脚本：

[[email protected] local]# ./jdk-8u111-nb-8_2-linux-x64.sh 
Configuring the installer...
Searching for JVM on the system...
Preparing bundled JVM ...

Extracting installation data...
Running the installer wizard...

（6）配置系统变量。在/etc/profile文件末尾加入以下系统变量：

JAVA_HOME=/usr/local/jdk1.8.0_111
JRE_HOME=/usr/local/jdk1.8.0_111/jre
PATH=$JAVA_HOME/bin:$JRE_HOME/bin:$PATH
CLASSPATH=.:$JAVA_HOME/jre/lib/ext:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export JAVA_HOME JRE_HOME PATH CLASSPATH

（7）使文件/etc/profile中的系统变量生效（本次只是临时生效，下次系统启动自动加载系统变量，才会永久生效）：

[[email protected] ~]# source /etc/profile

（9）验证配置是否正确：

[[email protected] ~]# echo $PATH
/usr/local/jdk1.8.0_111/bin:/usr/local/jdk1.8.0_111/jre/bin:/usr/lib64/qt3.3/bin:/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin:/root/bin
[[email protected] ~]# java -version
java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.111-b14, mixed mode)