How to work with environment variables?

Question

I am developing an application that works with files (save and upload) and have to work with system variables to determine where to save these files.

My question is: Is there any way to use variables independent of the operating system? If so, how should I proceed. For example, I know that if I put a variable caminho, for example in windows as follows:

%caminho%\algum_dir\algum_arquivo.exemplo

He will convert %caminho% for the string contained in this variable. The same goes for Linux, only using $caminho. So, in short, I wanted to know if it is possible to use some kind of nomenclature for the program to detect an environment variable, which has a name defined by me, independent of the OS, since the program will be in Java.

Answer 1

I think what you want is the method getenv(). He is responsible for reading the environment variables and takes care of the specifics of the operating systems. I removed this code from official tutorial:

import java.util.Map;

class Main {
    public static void main (String[] args) {
        Map<String, String> env = System.getenv();
        for (String envName : env.keySet()) System.out.format("%s=%s%n", envName, env.get(envName));
    }
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.

I imagine you can get what you want from there. Documentation from Map. Essentially the key is the variable and the value is its content.