解惑一下，解惑一下。

很简单啊。

public class Box {
    private int length;
    private int width;
    private int height;

    public void set(int l, int w, int h) {
        this.length = l;
        this.width = w;
        this.height = h;
    }

    public void volume() {
        System.out.println(length * width * height);
    }
}