1.打开terminal

/usr/libexec/java_home -V

2.查看当前java版本

java -version

3.切换到jdk1.8

open ~/.bash_profile

加上这两句

JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_211.jdk/Contents/Home

export JAVA_HOME

4.更新配置

source ~/.bash_profile

qiang@xiaocaidembp ~$ source ~/.bash_profile

5.查看java版本

java -version