java 产生一个 -1000 到 1000的 随机数

package test;
import java.awt.*;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.Random;
import javax.swing.*;
public class Frame{
public int getRandom(){
Random r = new Random();
return r.nextInt(2000) - 1000;
}
public static void main(String[] args)
{
Frame f = new Frame();
for(int i=0; i