centos jdk

#vim /etc/profile

export JAVA_HOME=/usr/java/jdk1.8.0_144
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.;${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH

使环境变量生效

source /etc/profile

添加软链接

ln -s /usr/local/java/jdk1.8.0_171/bin/java /usr/bin/java