vi /etc/profile 
export JAVA_HOME=/opt/jdk1.7.0_79
export JAVA_BIN=$JAVA_HOME/bin
export JAVA_LIB=$JAVA_HOME/lib
export CLASSPATH=.:$JAVA_LIB/tools.jar:$JAVA_LIB/dt.jar
export PATH=$JAVA_BIN:$PATH

source /etc/profile     // 刷新

linux jdk环境变量配置