CentOS 7.5下Java环境的安装配置

1、查看系统中的java环境

　　[root@localhost ~]# java -version

　　openjdk version "1.8.0_101"

　　OpenJDK Runtime Environment (build 1.8.0_101-b13)

　　OpenJDK 64-Bit Server VM (build 25.101-b13, mixed mode)

　　进一步查看JDK信息：

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

　　javapackages-tools-3.4.1-11.el7.noarch

　　java-1.8.0-openjdk-headless-1.8.0.101-3.b13.el7_2.x86_64

　　python-javapackages-3.4.1-11.el7.noarch

　　tzdata-java-2016f-1.el7.noarch

　　java-1.8.0-openjdk-1.8.0.101-3.b13.el7_2.x86_64

　　卸载 OpenJDK：rpm -e --nodeps

　　[root@localhost ~]# rpm -e --nodeps javapackages-tools-3.4.1-11.el7.noarch

　　[root@localhost ~]# rpm -e --nodeps java-1.8.0-openjdk-headless-1.8.0.101-3.b13.el7_2.x86_64

　　[root@localhost ~]# rpm -e --nodeps python-javapackages-3.4.1-11.el7.noarch

　　[root@localhost ~]# rpm -e --nodeps tzdata-java-2016f-1.el7.noarch

　　[root@localhost ~]# rpm -e --nodeps java-1.8.0-openjdk-1.8.0.101-3.b13.el7_2.x86_64

2、安装jdk

　　下载jdk的rpm安装包上传到/usr/local/java

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

cd /usr/local/java 进入jdk所在的文件夹执行安装命令：

[root@localhost java]# rpm -ivh jdk-8u91-linux-x64.rpm

准备中... ################################# [100%]

正在升级/安装...

1:jdk1.8.0_91-2000:1.8.0_91-fcs ################################# [100%]

Unpacking JAR files...

tools.jar...

plugin.jar...

javaws.jar...

deploy.jar...

rt.jar...

jsse.jar...

charsets.jar...

localedata.jar...

jfxrt.jar...

不报错就安装成功

验证：

[root@localhost java]# java -version

java version "1.8.0_91"

Java(TM) SE Runtime Environment (build 1.8.0_91-b14)

Java HotSpot(TM) 64-Bit Server VM (build 25.91-b14, mixed mode)

3、环境变量设置

修改系统环境变量文件

vi + /etc/profile

[root@localhost java]# vi + /etc/profile

fi

HOSTNAME=`/usr/bin/hostname 2>/dev/null`

HISTSIZE=1000

if [ "$HISTCONTROL" = "ignorespace" ] ; then

export HISTCONTROL=ignoreboth

else

export HISTCONTROL=ignoredups

fi

export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL

JAVA_HOME=/usr/java/jdk1.8.0_91

JRE_HOME=/usr/java/jdk1.8.0_91/jre

PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin

CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib

export JAVA_HOME JRE_HOME PATH CLASSPATH

# By default, we want umask to get set. This sets it for login shell

# Current threshold for system reserved uid/gids is 200

# You could check uidgid reservation validity in

# /usr/share/doc/setup-*/uidgid file

if [ $UID -gt 199 ] && [ "`id -gn`" = "`id -un`" ]; then

umask 002

else

umask 022

fi

for i in /etc/profile.d/*.sh ; do

if [ -r "$i" ]; then

if [ "${-#*i}" != "$-" ]; then

. "$i"

else

. "$i" >/dev/null

fi

fi

done

unset i

unset -f pathmunge

"/etc/profile" 82L, 1972C

红色字体的为添加的设置，通常java安装在/usr/java/目录下

使修改生效

[root@localhost ~]# source /etc/profile //使修改立即生效

验证配置：

[root@localhost java]# echo $PATH

/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin:/usr/java/jdk1.8.0_91/bin:/usr/java/jdk1.8.0_91/jre/bin

这样就完成的对整个java环境的配置