import java.awt.*;import java.awt.geom.*;import javax.swing.*;public class DrawTest {
     public static void main (String [] args){    JFrame window = new DrawFrame();    window.setTitle("绘制图形");    window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);    window.setBounds(100,100,600,400);    window.setVisible(true);}}//窗口类class DrawFrame extends JFrame{
         public DrawFrame(){        add(new DrawComponent());        pack();    }}//图形类class DrawComponent extends JComponent{
         private static final int DEAFULT_WIDTH = 400;    private static final int DEFAULT_HEIGHT = 400;    public void paintComponent(Graphics g){        Graphics2D g2 = (Graphics2D)g;        //绘制矩形        double leftx = 100;        double topy = 100;        double width = 200;        double height = 150;        Rectangle2D rect = new Rectangle2D.Double(leftx,topy ,width,height);        g2.draw(rect);        //绘制椭圆        Ellipse2D ellipse = new Ellipse2D.Double();        ellipse.setFrame(rect);        g2.draw(ellipse);        //绘制直线        g2.draw(new Line2D.Double(leftx,topy,leftx + width ,topy + height));        //画正圆        double centerx = rect.getCenterX();        double centery = rect.getCenterY();        double radius = 150;        Ellipse2D circle = new Ellipse2D.Double();        circle.setFrameFromCenter(centerx, centery,centerx+radius,centery+radius);        g2.draw(circle);    }}