在MAC上查找和设置$JAVA_HOME

可以使用工具命令“/usr/libexec/java_home”来定位JAVA_HOME：

定位JAVA：

/usr/libexec/java_home -V
Matching Java Virtual Machines (1):
    1.8.0_25, x86_64:   "Java SE 8" /Library/Java/JavaVirtualMachines/jdk1.8.0_25.jdk/Contents/Home

/Library/Java/JavaVirtualMachines/jdk1.8.0_25.jdk/Contents/Home

另外可以使用-V选项列出所有版本的JAVA_HOME：

$ /usr/libexec/java_home -V
Matching Java Virtual Machines (3):
    1.7.0_45, x86_64:   "Java SE 7" /Library/Java/JavaVirtualMachines/jdk1.7.0_45.jdk/Contents/Home
    1.6.0_65-b14-462, x86_64:   "Java SE 6" /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home
    1.6.0_65-b14-462, i386: "Java SE 6" /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home

/Library/Java/JavaVirtualMachines/jdk1.7.0_45.jdk/Contents/Home

配置JAVA_HOME：

$ cat ~/.profile

JAVA_HOME=`/usr/libexec/java_home`
export JAVA_HOME

$ echo $JAVA_HOME
/Library/Java/JavaVirtualMachines/jdk1.7.0_45.jdk/Contents/Home
$ source ~/.profile 
$java