Java 获得当前路径

1、利用System.getProperty()函数获取当前路径： 

 System.out.println(System.getProperty("user.dir"));//user.dir指定了当前的路径

2、使用File提供的函数获取当前路径： 

 File directory = new File("");//设定为当前文件夹
 try{
     System.out.println(directory.getCanonicalPath());//获取标准的路径
     System.out.println(directory.getAbsolutePath());//获取绝对路径
 }catch(Exceptin e){}

File.getCanonicalPath()和File.getAbsolutePath()大约只是对于new File(".")和new File("..")两种路径有所区别。 

# 对于getCanonicalPath()函数，“."就表示当前的文件夹，而”..“则表示当前文件夹的上一级文件夹 
# 对于getAbsolutePath()函数，则不管”.”、“..”，返回当前的路径加上你在new File()时设定的路径 
# 至于getPath()函数，得到的只是你在new File()时设定的路径 

比如当前的路径为 C:\test ： 

 File directory = new File("abc");
 directory.getCanonicalPath(); //得到的是C:\test\abc
 directory.getAbsolutePath();    //得到的是C:\test\abc
 direcotry.getPath();                    //得到的是abc

 File directory = new File(".");
 directory.getCanonicalPath(); //得到的是C:\test
 directory.getAbsolutePath();    //得到的是C:\test\.
 direcotry.getPath();                    //得到的是.

 File directory = new File("..");
 directory.getCanonicalPath(); //得到的是C:\
 directory.getAbsolutePath();    //得到的是C:\test\..
 direcotry.getPath();                    //得到的是..

另外：System.getProperty()中的字符串参数如下： 

 System.getProperty()参数大全
 # 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