給您一個例子：

import javax.swing.*;

import java.awt.*;

import java.awt.geom.*;

public class paint

{

public static void main(String[] args)

{

CenteredFrame frame=new CenteredFrame();

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true);

}

}

class CenteredFrame extends JFrame

{

private static final int WIDTH=400;

private static final int HEIGHT=400;

public CenteredFrame()

{

Toolkit kit=Toolkit.getDefaultToolkit();

Dimension screenSize=kit.getScreenSize();

int screenHeight = screenSize.height;

int screenWidth = screenSize.width;

int X = (screenWidth - WIDTH)/2;

int Y = (screenHeight - HEIGHT)/2;

setLocation(X, Y);

setSize(WIDTH,HEIGHT);

Container con=getContentPane();

StringPanel panel=new StringPanel();

con.add(panel);

setResizable(true);

}

}

class StringPanel extends JPanel

{

public void paintComponent(Graphics g)

{

Graphics2D g2=(Graphics2D)g;

int x[]=new int[33];

int y[]=new int[33];

x[0]=0;

y[0]=0;

for(int i=1;i<=16;i++)

{

x[i]=184+i;

y[i]=200-(17-i)*(17-i);

x[i+16]=i+200;

y[i+16]=200-i*i;

}

g.drawPolyline(x,y,33);

Line2D L1 = new Line2D.Double(0,200,400,200);

g2.draw(L1);

Line2D L2=new Line2D.Double(200,40,200,400);

g2.draw(L2);

Line2D L3=new Line2D.Double(380,195,395,200);

g2.draw(L3);

Line2D L4=new Line2D.Double(380,205,395,200);

g2.draw(L4);

Line2D L5=new Line2D.Double(200,40,195,55);

g2.draw(L5);

Line2D L6=new Line2D.Double(200,40,205,55);

g2.draw(L6);

g.drawString("X",370,190);

g.drawString("Y",205,40);

}

}