Java Graphics_3
package com.han;import java.awt.Canvas;import java.awt.Graphics;import javax.swing.JFrame;@SuppressWarnings("serial")public class Graphics_3 extends JFrame {private static final int OVAL_WIDTH = 80;private static final int OVAL_HEIGHT = 80;public Graphics_3() {// TODO Auto-generated constructor stubCanvas canvas = new Canvas() {@Overridepublic void paint(Graphics g) {//super.paint(g); // for the one containing children components, this is necessary.g.drawOval(10, 10, OVAL_WIDTH, OVAL_HEIGHT);g.drawOval(80, 10, OVAL_WIDTH, OVAL_HEIGHT);g.drawOval(150, 10, OVAL_WIDTH, OVAL_HEIGHT);g.drawOval(50, 70, OVAL_WIDTH, OVAL_HEIGHT);g.drawOval(120, 70, OVAL_WIDTH, OVAL_HEIGHT);}};this.add(canvas); // add()方法最早出现在Container中，所以我们无法在Canvas中添加组件。 }/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubGraphics_3 frame = new Graphics_3();frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);frame.setTitle("Draw circles");frame.setSize(300, 200);frame.setVisible(true);}}