mac个人记录部分操作
mac卸载java:
sudo rm -fr /Library/Internet Plug-Ins/JavaAppletPlugin.plugin
sudo rm -fr /Library/PreferencesPanes/JavaControlPanel.prefpane
ls /Library/Java/JavaVirtualMachines/
输出：jdk-9.0.1.jdk
sudo rm -rf /Library/Java/JavaVirtualMachines/jdk-9.0.1.jdk