/etc/profile
(java 环境变量)----------------------------------------------
JAVA_HOME=/usr/local/jre160 （默认jDK安装路径）
PATH=$JAVA_HOME/bin:$PATH
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar
export JAVA_HOME
export PATH
export CLASSPATH
-----------------------------------------------
