Java 画一个5X5的方形矩阵

效果图如下：

思路：创建一个窗口，使其居中于屏幕中央，使用drawRect(x, y, width, height)画正方形。

 1 import java.awt.Graphics;
 2 import java.awt.Insets;
 3 import java.awt.Toolkit;
 4 import java.awt.event.WindowAdapter;
 5 import java.awt.event.WindowEvent;
 6 
 7 import javax.swing.JFrame;
 8 
 9 public class FiveXFive extends JFrame {
10     
11     public static void main(String[] args) {
12         FiveXFive f = new FiveXFive();
13         f.launchFrame();
14         
15     }
16     
17     public void launchFrame() {
18         // The width & Height of the window
19         final int formWidth = 500;
20         final int formHeight = 500;
21         // The width & Height of the screen
22         int screenWidth = (int)Toolkit.getDefaultToolkit().getScreenSize().getWidth();
23         int screenHeight = (int)Toolkit.getDefaultToolkit().getScreenSize().getHeight();
24         
25         // Set title, size, location & visible
26         this.setTitle("Hello World! I'm coming!");
27         // width + left + right, height + top + bottom
28         this.setSize(formWidth+8+8, formHeight+31+8);
29         // set window in the middle
30         this.setLocation((screenWidth-formWidth)/2, (screenHeight-formHeight)/2);
31         this.setVisible(true);
32         
33         Insets insets = this.getInsets();
34         System.out.println("top: " + insets.top);
35         System.out.println("bottom: " + insets.bottom);
36         System.out.println("left: " + insets.left);
37         System.out.println("right: " + insets.right);
38         
39         this.addWindowListener(new WindowAdapter() {
40             public void windowClosing(WindowEvent e) {
41                 System.exit(0);
42             }
43         });
44     }
45     
46     public void paint(Graphics g) {
47         g.drawLine(8, 31, 508, 531);
48         g.drawLine(8, 531, 508, 31);
49         for (int y = 31; y < (500+31); y += 100) {
50             for (int x = 8; x < (500+8); x += 100) {
51                 g.drawRect(x, y, 100, 100);
52             }
53         }
54     }
55 }