cd /usr/lib
sudo mkdir jvm
tar -xzf jdk-8u91-linux-x64.tar.gz -C /usr/lib/jvm
cd /usr/lib/jvm
sudo mv jdk1.8.0_91 java8
sudo cp /etc/profile /etc/profile.bak
vim /etc/profile
#添加如下，注意自己的路径
export JAVA_HOME=/usr/bin/jvm/java8
export JRE_HOME=${JAVA_HOME}/jre 
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib 
export PATH=${JAVA_HOME}/bin:$PATH 
#:wq
source /etc/profile
java -version
#会有如下信息
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)