java中关于获取当前代码执行路径的问题(System.getProperty("user.dir"))

/**
 * 获取项目执行时候的根路径
 */
public class MyUrlDemo {
 public static void main(String[] args) throws Exception {
  MyUrlDemo muDemo = new MyUrlDemo();
   muDemo.showURL();
 }
 public void showURL() throws IOException {
  // 第1种：
  File directory = new File("");// 参数为空
  String courseFile = directory.getCanonicalPath();
  System.out.println("path1: " + courseFile);
  // 第2种：
  System.out.println("path2:" + System.getProperty("user.dir"));
 }
}

注意:这里很关键 这里很关键 这里很关键
将代码打成jar

测试:
D:\hangyi\ycwlkj\out\artifacts\test_jar>java -jar test.jar
path1: D:\hangyi\ycwlkj\out\artifacts\test_jar
path2:D:\hangyi\ycwlkj\out\artifacts\test_jar

C:\>cd C:\Users\Administrator\Desktop

C:\Users\Administrator\Desktop>java -jar D:\hangyi\ycwlkj\out\artifacts\test_jar\test.jar
path1: C:\Users\Administrator\Desktop
path2:C:\Users\Administrator\Desktop