JDK安装步骤

sudo gedit /etc/profile

设置JAVA必要的环境变量

#set Java environment

export JAVA_HOME=/dengyang/jdk1.8.0_56

export JRE_HOME=$JAVA_HOME/jre

export CLASSPATH=.:$JAVA_HOME/lib:$JRE_HOME/lib:$CLASSPATH

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

环境变量生效

source /etc/profile