1. 创建一个servlet
1 package ztq.servlet.study;
2
3 import java.awt.Color;
4 import java.awt.Font;
5 import java.awt.Graphics;
6 import java.awt.image.BufferedImage;
7 import java.io.IOException;
8 import java.util.Random;
9
10 import javax.imageio.ImageIO;
11 import javax.servlet.ServletException;
12 import javax.servlet.http.HttpServlet;
13 import javax.servlet.http.HttpServletRequest;
14 import javax.servlet.http.HttpServletResponse;
15
16 public class ServletDemo1 extends HttpServlet {
17 public void doGet(HttpServletRequest request, HttpServletResponse response)
18 throws ServletException, IOException {
19 //通知浏览器不要缓存
20 response.setHeader("Expires", "-1");
21 response.setHeader("Cache-Control", "no-cache");
22 response.setHeader("Pragma", "no-cache");
23
24 int width = 120;
25 int height = 25;
26 //创建一副内存图像
27 BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
28
29 //得到属于该图像的画笔
30 Graphics g = bi.getGraphics();
31
32 //画边框
33 g.setColor(Color.BLACK);
34 g.drawRect(0, 0, width, height);
35
36 //填充背景色
37 g.setColor(Color.GRAY);
38 g.fillRect(1, 1, width - 2, height - 2);
39
40 //画随机干扰线
41 g.setColor(Color.GREEN);
42 Random r = new Random();
43 for(int i = 0; i < 10; i++){
44 g.drawLine(r.nextInt(width), r.nextInt(height), r.nextInt(width), r.nextInt(height));
45 }
46
47 //画随机数字
48 g.setColor(Color.RED);
49 g.setFont(new Font("宋体", Font.BOLD|Font.ITALIC, 20));
50 int x = 23;
51 for(int i = 0; i < 4; i++){
52 g.drawString(r.nextInt(10) + "", x, 20);
53 x += 20;
54 }
55
56 //输出到浏览器的页面上
57 ImageIO.write(bi, "jpg", response.getOutputStream());
58
59 }
60 public void doPost(HttpServletRequest request, HttpServletResponse response)
61 throws ServletException, IOException {
62 doGet(request, response);
63 }
64 }
2. 创建一个Html页面
1 <!DOCTYPE html>
2 <html>
3 <head>
4 <title>登录</title>
5
6 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
7 <meta http-equiv="description" content="this is my page">
8 <meta http-equiv="content-type" content="text/html; charset=UTF-8">
9
10 <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->
11
12 </head>
13
14 <body>
15 <form action = "" method = "post">
16 用户名：<input type = "text" name = "username" /><br /><br />
17 密码： <input type = "password" name = "password" /><br /><br />
18 验证码：<input type = "text" name = "code" />
19 <img src = "/JavaWeb_Servlet_Study/servlet/ServletDemo1">
20 <a href = "javascript:toRefresh()">看不清</a><br /><br />
21 <input type = "submit" value = "登录" />
22 </form>
23 <script type = "text/javascript">
24 function toRefresh(){
25 document.location.href = "login.html";
26 }
27 </script>
28 </body>
29 </html>
时间： 2024-10-12 14:54:40