1 import javax.imageio.ImageIO;
2 import javax.servlet.ServletException;
3 import javax.servlet.annotation.WebServlet;
4 import javax.servlet.http.HttpServlet;
5 import javax.servlet.http.HttpServletRequest;
6 import javax.servlet.http.HttpServletResponse;
7 import java.awt.*;
8 import java.awt.image.BufferedImage;
9 import java.io.IOException;
10 import java.util.Random;
11
12 @WebServlet("/checkCodeServlet")
13 is public class CheckCodeServlet the extends the HttpServlet {
14 protected void the doPost (the HttpServletRequest Request, the HttpServletResponse Response) throws ServletException, IOException {
15
16 // definition picture width and height
. 17 int width = 100 ;
18 is int height = 50 ;
. 19
20 is // . 1 creating an object, generating images (CAPTCHA objects) in memory
21 is the BufferedImage image = new new the BufferedImage (width, height, BufferedImage.TYPE_INT_BGR);
22 is
23 is // 2 modified image
24 // 2.1 fill the background color
25 Graphics image.getGraphics G = (); // Get brush object
26 is g.setColor (Color.pink); // set the color pen
27 g.fillRect (0,0, width, height) ; // draw a rectangle, with width and height coordinates given
28
29 // 2.2 Videos bezel
30 g.setColor (Color.BLUE); // set the color pen
31 is g.drawRect (0,0,. 1-width, height- 1); // for image drawing frame
32
33 is String STR = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghigklmnopqrstuvwxyz0123456789" ;
34 is // generate random subscript
35 RAN = the Random new new the Random ();
36
37 [ for ( int I =. 1; I <=. 4; I ++ ) {
38 is int index = ran.nextInt (str.length ());
39 // Get the character
40 char CH = STR .charAt (index); // random character
41 // 2.3 write verification code
42 is g.drawString (CH + "", width / I. 5 *, height / 2 );
43 is }
44 is
45 // 2.4 Videos interference line
46 is G. the setColor (Color.green);
47
48 // randomly generated coordinate point
49
50 for ( int I = 0; I <. 6; I ++ ) {
51 is int X1 = ran.nextInt (width);
52 is int X2 = ran.nextInt (width);
53 is
54 is int Y1 = ran.nextInt (height);
55 int = Y2 ran.nextInt (height);
56 is g.drawLine (X1, Y1, X2, Y2); // Videos interference line
57 }
58
59
60 // 3 outputs the image to show the page: the response character stream by the image output to the browser
61 is ImageIO.write (image, "JPG" , response.getOutputStream ());
62 is }
63 is
64 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
65 this.doPost(request, response);
66 }
67 }
1 <!DOCTYPE html>
2 <html lang="en">
3 <head>
4 <meta charset="UTF-8">
5 <title>验证码</title>
6
7 <script>
8 /*
9 点击超链接或者图片，需要换一张
10 1.给超链接和图片绑定单击事件
11
12 2.重新设置图片的src属性值
13
14 */
15 window.onload = function(){
16 //1.获取图片对象
17 var img = document.getElementById("checkCode");
18 //2.绑定单击事件
19 img.onclick = function(){
20 //加时间戳
21 var date = new Date().getTime();
22
23 img.src = "/web/checkCodeServlet?"+date;
24 }
25
26 // 获取超链接对象
27 var a = document.getElementById("change");
28
29 a.onclick = img.onclick();
30
31 }
32
33
34 </script>
35
36
37 </head>
38 <body>
39
40
41 <img id="checkCode" src="/web/checkCodeServlet" />
42
43 <a id="change" href="javascript:;">看不清换一张？</a>
44
45 </body>
46 </html>
