參考：http://www.mkyong.com/java/how-to-set-java_home-environment-variable-on-mac-os-x/
如果用bash，修改~/.bash_profile 或 ~/.profile；
如果用zsh，修改～/.zshrc
修改這些文件之后，重修打開terminal，配置不會丟
首先確保已經安裝了jdk：
## check the present running java which java ## check java version java -version
以zsh為例：
1 ## check all the available jdk 2 /usr/libexec/java_home -V 3 4 ## check the top jdk 5 /usr/libexec/java_home 6 7 ## check some jdk (eg. version 1.7) 8 /usr/libexec/java_home -v 1.7 9 10 ## edit .zshrc to set java_home variable 11 vim ~/.zshrc 12 13 ## add the following line into the file 14 export JAVA_HOME=$(/usr/libexec/java_home) 15 16 ## you can also use the following line to set the variable, which is not recommended, only for older mac os. 17 ## export JAVA_HOME=/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home 18 19 ##let the configuration in .zshrc take effect 20 source ~/.zshrc 21 22 ## check if configure succeed 23 echo $JAVA_HOME