如何在java中获取屏幕DPI？

import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.Toolkit;

public class ScreenDPI {
    public static void main(String[] args) {
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        GraphicsDevice gd = ge.getDefaultScreenDevice();
        GraphicsConfiguration gc = gd.getDefaultConfiguration();
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        Dimension screenSize = toolkit.getScreenSize();
        Insets insets = toolkit.getScreenInsets(gc);
        double width = screenSize.getWidth() - insets.left - insets.right;
        double height = screenSize.getHeight() - insets.top - insets.bottom;
        double dpi = (gc.getBounds().getWidth() / width) * 25.4;
        System.out.println("屏幕DPI: " + dpi);
    }
}