Java 获取当前路径

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

    /**
     * java 系统属性
     */
    public static void systemProperty() {

        String property = System.getProperty("java.version");
        System.out.println("当前java版本为：" + property);
        System.out.println("Java 运行时环境的安装目录：" + System.getProperty("java.home"));

        String property1 = System.getProperty("os.name");
        System.out.println("当前操作系统为：" + property1);
        System.out.println("当前用户为：" + System.getProperty("user.name"));
        System.out.println("当前用户目录为：" + System.getProperty("user.home"));
        System.out.println("当前工作目录为：" + System.getProperty("user.dir"));


    }