How to set file path dynamically in Java program?

Question

I want to dynamically set the document root in a program in Java. My Java program accepts 2 inputs:

1. document root path as String
2. an Int which I'm using for some calculations.

I set this document root in program, so that any use of File file=new File(filename) will fetch the specified file from the document root path:

String f_path=args[0]; //within main().

f_path could be any path in that system other than the root directory of the program. Currently, when I do File file=new File(filename); it searches for the specified file in the program's root directory. How can I change this to f_path?

Answer 1

You should craft absolute paths, for example using the File(String parent, String path) constructor :

new File(f_path, filename)

Answer 2

You may use the File constructor which takes a parent parameter : File(String parent, String child ) , e.g :

File file=new File(f_path, fileName);