如何使用 exec 在 Java 中设置环境变量?

I'm trying to set an environment variable, and read it back to verify it was actually set.

我有以下内容:

import java.io.IOException;

public class EnvironmentVariable
{
    public static void main(String[] args) throws IOException
    {
        Runtime.getRuntime().exec("cmd.exe set FOO=false");

        String s = System.getenv("FOO");
        System.out.println(s);
    }
}

但是，FOO 似乎总是为空，这意味着它可能没有正确设置.