java编程：怎么画一个正方形?不用applet,只是application编程,用java怎么画一个蓝色的正方形（最好实心和空心的各画一个）.-------------------------------------------------------------------希望给出完整代码,----------------------------------------------------
网友回答
没多少代码.如下.
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import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
public class Foo extends JFrame implements ActionListener {
JPanel panel = null;
public Foo() {
panel = new JPanel();
panel.setLayout(null);
getContentPane().add(panel, BorderLayout.CENTER);
JButton btnNewButton = new JButton(Click);
btnNewButton.setBounds(22, 10, 93, 23);
btnNewButton.addActionListener(this);
panel.add(btnNewButton);
setSize(200, 200);
setVisible(true);
} public static void main(String[] args) {
new Foo();
} public void actionPerformed(ActionEvent e) {
Graphics g = panel.getGraphics();
g.drawRect(10, 50, 50, 50);
g.fillRect(110, 50, 50, 50);
}}