这个程序很简单，没有什么好说的了，希望大家多多指教一下,在JDK1.6下通过。 import java.awt.*;import java.awt.event.*;import java.util.*;public class Draw extends WindowAdapter implements ActionListener,WindowListener{Canvas c;TextField radius,x,y;Button b; public static void main(String args[]) {Draw d=new Draw();  Frame f=new Frame("画布画圆");  d.c=new Canvas();  d.x=new TextField(5);  d.y=new TextField(5);  d.radius=new TextField(5);  d.b=new Button("清空画布");  Label x1=new Label("请输入左上角x：");  Label y1=new Label("请输入左上角y：");  Label radius1=new Label("请输入半径：");  Panel p=new Panel();  f.setLayout(new BorderLayout());  p.setLayout(new FlowLayout());  f.add("Center",d.c);  f.add("South",p);  p.add(radius1);p.add(d.radius);p.add(x1);p.add(d.x);  p.add(y1);p.add(d.y);p.add(d.b);  d.x.addActionListener(d);  d.y.addActionListener(d);  d.radius.addActionListener(d);  d.b.addActionListener(d);  f.addWindowListener(d);  f.setSize(600,400);  f.setVisible(true); } public void actionPerformed(ActionEvent e) {if(e.getSource()==b)  {c.repaint();   x.setText("");y.setText("");radius.setText("");   radius.requestFocusInWindow();  }  else  {if(!(radius.getText()==""||x.getText()==""||y.getText()==""))   {c.getGraphics().drawOval(Integer.parseInt(x.getText()),Integer.parseInt(y.getText()),2*Integer.parseInt(radius.getText()),2*Integer.parseInt(radius.getText()));   }  } } public void windowClosing(WindowEvent e) {System.exit(0); }}

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