输出随机图片(CAPTCHA图像):Completely Automated Public Turing Test to Tell Computers and Humans Apart (全自动区分计算机和人类的测试)
相关主要类(JDK 查看API)
BufferedImage:内存图像
Graphics:画笔
ImageIO:输出图像
放在html页面上<img src/>
注意:浏览器默认会缓存图片
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
|
public static int WIDTH = 120 ; public static int HEIGHT = 25 ; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType( "text/html" ); //创建内存图像 BufferedImage image = new BufferedImage(WIDTH,HEIGHT,BufferedImage.TYPE_INT_RGB); //勾勒图像 Graphics graphics = image.getGraphics(); //设置背景 graphics.setColor(Color.WHITE); graphics.fillRect( 0 , 0 , WIDTH, HEIGHT); //设置边框 graphics.setColor(Color.BLUE); graphics.drawRect( 1 , 1 , WIDTH- 2 , HEIGHT- 2 ); //画干扰线 graphics.setColor(Color.YELLOW); for ( int i= 0 ;i< 8 ;i++){ int xStart = new Random().nextInt(WIDTH); int yStart = new Random().nextInt(HEIGHT); int xEnd = new Random().nextInt(WIDTH); int yEnd = new Random().nextInt(HEIGHT); graphics.drawLine(xStart, yStart, xEnd, yEnd); } //写随机数 graphics.setColor(Color.RED); int x = 5 ; for ( int i= 0 ;i< 4 ;i++){ graphics.drawString( new Random().nextInt( 9 )+ "" , x, 20 ); x+= 30 ; } response.setContentType( "image/jpeg" ); //设置响应格式 ImageIO.write(image, "jpeg" , response.getOutputStream()); } |
感谢阅读,希望能帮助到大家,谢谢大家对本站的支持!
原文链接:http://blog.csdn.net/alex_zhuang/article/details/7249850