【Java】使用者設定檔路徑(User Shell Folder)

有了這個就可以輕鬆取得使用者相關資料夾的相對路徑，不用因為設了絕對路徑，換一台電腦操作，因為使用者名稱不同，導致檔案路徑不同，造成找不到檔案的窘境。


Java 6 up
透過System.getProperty(string key)取得使用者系統資訊，以下參數用法參考至Java 7說明文件

java.version	Java Runtime Environment version
java.vendor	Java Runtime Environment vendor
java.vendor.url	Java vendor URL
java.home	Java installation directory
java.vm.specification.version	Java Virtual Machine specification version
java.vm.specification.vendor	Java Virtual Machine specification vendor
java.vm.specification.name	Java Virtual Machine specification name
java.vm.version	Java Virtual Machine implementation version
java.vm.vendor	Java Virtual Machine implementation vendor
java.vm.name	Java Virtual Machine implementation name
java.specification.version	Java Runtime Environment specification version
java.specification.vendor	Java Runtime Environment specification vendor
java.specification.name	Java Runtime Environment specification name
java.class.version	Java class format version number
java.class.path	Java class path
java.library.path	List of paths to search when loading libraries
java.io.tmpdir	Default temp file path
java.compiler	Name of JIT compiler to use
java.ext.dirs	Path of extension directory or directories
os.name	Operating system name
os.arch	Operating system architecture
os.version	Operating system version
file.separator	File separator ("/" on UNIX)
path.separator	Path separator (":" on UNIX)
line.separator	Line separator ("\n" on UNIX)
user.name	User's account name
user.home	User's home directory
user.dir	User's current working directory

C# or Windows Environment
以下參考至User Shell Folder
%USERPROFILE%\Desktop     Desktop
%USERPROFILE%\Start Menu\Programs   Programs
%USERPROFILE%\My Documents            My Documents