安装Java环境
yum -y install java-1.8.0-openjdk.x86_64 java-1.8.0-openjdk-devel.x86_64
查看安装后的配置
java -version
openjdk version "1.8.0_181"OpenJDK Runtime Environment (build 1.8.0_181-b13)OpenJDK 64-Bit Server VM (build 25.181-b13, mixed mode)
可以查看出当前的Java版本为1.8.0_181。
cat /etc/profile # /etc/profile# System wide environment and startup programs, for login setup# Functions and aliases go in /etc/bashrc# It's NOT a good idea to change this file unless you know what you# are doing. It's much better to create a custom.sh shell script in# /etc/profile.d/ to make custom changes to your environment, as this# will prevent the need for merging in future updates.pathmunge () { case ":${PATH}:" in *:"$1":*) ;; *) if [ "$2" = "after" ] ; then PATH=$PATH:$1 else PATH=$1:$PATH fi esac}if [ -x /usr/bin/id ]; then if [ -z "$EUID" ]; then # ksh workaround EUID=`/usr/bin/id -u` UID=`/usr/bin/id -ru` fi USER="`/usr/bin/id -un`" LOGNAME=$USER MAIL="/var/spool/mail/$USER"fi# Path manipulationif [ "$EUID" = "0" ]; then pathmunge /usr/sbin pathmunge /usr/local/sbinelse pathmunge /usr/local/sbin after pathmunge /usr/sbin afterfiHOSTNAME=`/usr/bin/hostname 2>/dev/null`HISTSIZE=1000if [ "$HISTCONTROL" = "ignorespace" ] ; then export HISTCONTROL=ignorebothelse export HISTCONTROL=ignoredupsfiexport PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL# 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 fileif [ $UID -gt 199 ] && [ "`/usr/bin/id -gn`" = "`/usr/bin/id -un`" ]; then umask 002else umask 022fifor i in /etc/profile.d/*.sh ; do if [ -r "$i" ]; then if [ "${-#*i}" != "$-" ]; then . "$i" else . "$i" >/dev/null fi fidoneunset iunset -f pathmungeexport http_proxy=http://10.241.1.1:8888export http_proxy=https://10.241.1.1:8888 cat .bash_profile
# .bash_profile# Get the aliases and functionsif [ -f ~/.bashrc ]; then . ~/.bashrcfi# User specific environment and startup programsPATH=$PATH:$HOME/binexport PATH
echo $JAVA_HOME
查看当前JAVA_HOME
查看当前目录，直至到真实目录非软连接。
配置JAVA_HOME
vim /etc/profile
export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.181-3.b13.el7_5.x86_64export JRE_HOME=$JAVA_HOME/jrePATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/binexport JAVA_HOME JRE_HOME CLASS_PATH PATH