JAVA获取当前工程路径(非web工程)

注:不适合web工程

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