java实现绘制矩形和椭圆并计算面积和周长

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import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

public class PCJFrame extends JFrame implements ActionListener

{

private JRadioButton radio_Rec,radio_Ell;

private JButton button_paint;

private JTextField text_perimeter,text_area;

public JTextField text_length,text_width;

public int l,w; private RectangleCanvas Rectangle;

private EllipseCanvas Ellipse;

public PCJFrame()

{

super("绘制平面图形并计算周长和面积");

this.setSize(600,300);

this.setLocation(200,100);

this.setBackground(Color.white);

this.setDefaultCloseOperation(EXIT_ON_CLOSE);

JPanel panel1=new JPanel(new FlowLayout(1));

this.getContentPane().add(panel1,"North");

ButtonGroup bgroup=new ButtonGroup();

radio_Rec=new JRadioButton("矩形",true);

panel1.add(radio_Rec);

bgroup.add(radio_Rec);

radio_Ell=new JRadioButton("椭圆",true);

panel1.add(radio_Ell);

bgroup.add(radio_Ell);

panel1.add(new Label("长度/长轴"));

text_length=new JTextField(10);

panel1.add(text_length);

panel1.add(new Label("宽度/短轴"));

text_width=new JTextField(10);

panel1.add(text_width);

button_paint=new JButton("绘图");

button_paint.addActionListener(this);

panel1.add(button_paint);

JPanel panel2=new JPanel(new FlowLayout(1));

this.getContentPane().add(panel2,"South");

text_perimeter=new JTextField(20);

panel2.add(new Label("周长"));

panel2.add(text_perimeter);

text_area=new JTextField(20);

panel2.add(new Label("面积"));

panel2.add(text_area);

this.setVisible(true);

}

public void actionPerformed(ActionEvent e)

{

double length=Double.parseDouble(text_length.getText());

double width=Double.parseDouble(text_width.getText());

l=(int)length;

w=(int)width;

if (Rectangle != null)

{

getContentPane().remove(Rectangle);

}

if (Ellipse != null)

{

getContentPane().remove(Ellipse);

}

Rectangle=new RectangleCanvas(l,w);