Java-System Properties, getProperty, setProperty__properties

http://docs.oracle.com/javase/tutorial/essential/environment/sysprop.html

tutorial/essential/environment/sysprop.html

http://www.leepoint.net/notes-java/io/30properties_and_preferences/40sysprops/10sysprop.html

http://blog.csdn.net/szwangdf/article/details/4366581

System Properties(系統屬性)：

The following table describes some of the most important system properties

Key	Meaning
"file.separator"	Character that separates components of a file path. This is "/" on UNIX and "\" on Windows.
"java.class.path"	Path used to find directories and JAR archives containing class files. Elements of the class path are separated by a platform-specific character specified in the path.separatorproperty.
"java.home"	Installation directory for Java Runtime Environment (JRE)
"java.vendor"	JRE vendor name
"java.vendor.url"	JRE vendor URL
"java.version"	JRE version number
"line.separator"	Sequence used by operating system to separate lines in text files
"os.arch"	Operating system architecture
"os.name"	Operating system name
"os.version"	Operating system version
"path.separator"	Path separator character used in java.class.path
"user.dir"	User working directory
"user.home"	User home directory
"user.name"	User account name

Properties props=System.getProperties(); //系統屬性System.out.println("Java的運行環境版本："+props.getProperty("java.version"));System.out.println("Java的運行環境供應商："+props.getProperty("java.vendor"));System.out.println("Java供應商的URL："+props.getProperty("java.vendor.url"));System.out.println("Java的安裝路徑："+props.getProperty("java.home"));System.out.println("Java的虛擬機器規範版本："+props.getProperty("java.vm.specification.version"));System.out.println("Java的虛擬機器規範供應商："+props.getProperty("java.vm.specification.vendor"));System.out.println("Java的虛擬機器正式名稱："+props.getProperty("java.vm.specification.name"));System.out.println("Java的虛擬機器實現版本："+props.getProperty("java.vm.version"));System.out.println("Java的虛擬機器實現供應商："+props.getProperty("java.vm.vendor"));System.out.println("Java的虛擬機器實現名稱："+props.getProperty("java.vm.name"));System.out.println("Java運行時環境規範版本："+props.getProperty("java.specification.version"));System.out.println("Java運行時環境規範供應商："+props.getProperty("java.specification.vender"));System.out.println("Java運行時環境正式名稱："+props.getProperty("java.specification.name"));System.out.println("Java的類格式版本號碼："+props.getProperty("java.class.version"));System.out.println("Java的類路徑："+props.getProperty("java.class.path"));System.out.println("載入庫時搜尋的路徑列表："+props.getProperty("java.library.path"));System.out.println("預設的臨時檔案路徑："+props.getProperty("java.io.tmpdir"));System.out.println("一個或多個擴充目錄的路徑："+props.getProperty("java.ext.dirs"));System.out.println("作業系統的名稱："+props.getProperty("os.name"));System.out.println("作業系統的構架："+props.getProperty("os.arch"));System.out.println("作業系統的版本："+props.getProperty("os.version"));System.out.println("檔案分隔字元："+props.getProperty("file.separator"));   //在 unix 系統中是＂／＂System.out.println("路徑分隔字元："+props.getProperty("path.separator"));   //在 unix 系統中是＂:＂System.out.println("行分隔字元："+props.getProperty("line.separator"));   //在 unix 系統中是＂/n＂System.out.println("使用者的賬戶名稱："+props.getProperty("user.name"));System.out.println("使用者的主目錄："+props.getProperty("user.home"));System.out.println("使用者的當前工作目錄："+props.getProperty("user.dir"));