Java中如何获取文件的路径

2.、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</p>
<p> 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){}</p>
<p>File.getCanonicalPath()和File.getAbsolutePath()大约只是对于 new File( "." )和 new File( ".." )两种路径有所区别。</p>
<p># 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</p>
<p>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</p>
<p>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.</p>
<p>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..</p>
<p> </p>
<p>
另外：System.getProperty()中的字符串参数如下：</p>
<p>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</p>