配置JDK-1.8

# centos7 install sun jdk #

download jdk8

##解压到 /usr/local

tar -zxvf jdk-8u131-linux-x64.tar.gz  -C  /usr/local/

mv jdk1.8.0_131 jdk-8

##配置环境变量


alternatives --install /usr/bin/java java /usr/local/jdk-8/bin/java 2

alternatives --config java

alternatives --install /usr/bin/jar jar /usr/local/jdk-8/bin/jar

alternatives --install /usr/bin/javac javac  /usr/local/jdk-8/bin/javac 2

alternatives --set jar /usr/local/jdk-8/bin/jar

alternatives --set javac /usr/local/jdk-8/bin/javac


PATH

export JAVA_HOME=/usr/local/jdk-8
export JRE_HOME=/usr/local/jdk-8/jre
export PATH=$PATH:/usr/local/jdk-8/bin:/usr/local/jdk-8/jre/bin


vim /etc/profile 
最后一行添加，开机生效