java編寫窗體程序，實現在窗體的畫布上根據用戶的輸入數據 畫壹個矩形。要求： a) 運行效果如下圖

import java.awt.Color;

import java.awt.Dimension;

import java.awt.Graphics;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JLabel;

import javax.swing.JPanel;

import javax.swing.JTextField;

public class Paint extends JFrame {

private JPanel panel1 = null;

private Panel panel2 = null;

private JPanel panel3 = null;

private JButton button = null;

private JLabel label1 = null;

private JLabel label2 = null;

private JLabel label3 = null;

private JLabel label4 = null;

private JTextField editField1 = null;

private JTextField editField2 = null;

private JTextField editField3 = null;

private JTextField editField4 = null;

public Paint(){

panel1 = new JPanel();

panel2 = new Panel();

panel3 = new JPanel();

button = new JButton("確定");

label1 = new JLabel("坐標x：");

label2 = new JLabel("坐標y：");

label3 = new JLabel("長度：");

label4 = new JLabel("寬度：");

editField1 = new JTextField(5);

editField2 = new JTextField(5);

editField3 = new JTextField(5);

editField4 = new JTextField(5);

panel1.setPreferredSize(new Dimension(250, 100));

panel1.add(label1);

panel1.add(editField1);

panel1.add(label2);

panel1.add(editField2);

panel1.add(label3);

panel1.add(editField3);

panel1.add(label4);

panel1.add(editField4);

panel3.setPreferredSize(new Dimension(250, 450));

panel3.add(panel1);

panel3.add(panel2);

panel3.add(button);

button.addActionListener(new ActionListener(){

@Override

public void actionPerformed(ActionEvent arg0) {

// TODO Auto-generated method stub

panel2.setX(Integer.parseInt(editField1.getText().toString()));

panel2.setY(Integer.parseInt(editField2.getText().toString()));

panel2.setWidth(Integer.parseInt(editField3.getText().toString()));

panel2.setHeight(Integer.parseInt(editField4.getText().toString()));

panel2.repaint();

}

});

this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

this.getContentPane().add(panel3);

this.pack();

this.setVisible(true);

}

/**

* @param args

*/

public static void main(String[] args) {

// TODO Auto-generated method stub

Paint paint = new Paint();

}

class Panel extends JPanel{

private int x = 0;

private int y = 0;

private int width = 0;

private int height = 0;

public Panel(){

this.setBackground(Color.blue);

this.setPreferredSize(new Dimension(250, 300));

}

public void paint(Graphics g){

super.paintComponent(g);

g.setColor(Color.black);

g.drawRect(x, y, width, height);

}

public void setX(int x) {

this.x = x;

}

public void setY(int y) {

this.y = y;

}

public void setWidth(int width) {

this.width = width;

}

public void setHeight(int height) {

this.height = height;

}

}

}