rpm -ivh jdk-7u79-linux-x64.rpm 
/etc/profile 添加  或者家目录的环境变量
export JAVA_HOME=/usr/java/latest/
export PATH=$JAVA_HOME/bin:$PATH
export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar

. /etc/profile
java -version