1 package cn.itcast.response;
2
3 import java.awt.Color;
4 import java.awt.Font;
5 import java.awt.Graphics;
6 import java.awt.Graphics2D;
7 import java.awt.image.BufferedImage;
8 import java.io.FileInputStream;
9 import java.io.IOException;
10 import java.io.InputStream;
11 import java.io.OutputStream;
12 import java.io.PrintWriter;
13 import java.util.Random;
14
15 import javax.imageio.ImageIO;
16 import javax.servlet.ServletException;
17 import javax.servlet.http.HttpServlet;
18 import javax.servlet.http.HttpServletRequest;
19 import javax.servlet.http.HttpServletResponse;
20
21 public class ResponseDemo extends HttpServlet {
22
23 public static final int WIDTH = 120;
24 public static final int HEIGHT = 45;
25
26 public void doGet(HttpServletRequest request, HttpServletResponse response)
27 throws ServletException, IOException {
28
29 BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
30 BufferedImage.TYPE_INT_RGB);
31
32 Graphics g = image.getGraphics();
33
34 // 1.设置背景色
35 setBackGround(g);
36
37 // 2.设置边框
38 setBorder(g);
39
40 // 3.画干扰线
41 drawRandomLine(g);
42
43 // 4.写随机数
44 drawRandomNum((Graphics2D) g);
45
46 // 5.图形写给浏览器
47 response.setContentType("image/jpeg");
48
49 //发头控制浏览器不要缓存
50 response.setDateHeader("expries", -1);
51 response.setHeader("Cache-Control", "no-cache");
52 response.setHeader("Pragma", "no-cache");
53 ImageIO.write(image, "jpg", response.getOutputStream());
54 }
55
56 private void drawRandomNum(Graphics2D g) {
57
58 g.setColor(Color.RED);
59 g.setFont(new Font("宋体",Font.BOLD,20));
60
61 String base = "\u7684\u4e00\u662f\u6211\u4e0d\u5728\u4eba";
62
63 int x=5;
64 for(int i=0;i<4;i++){
65
66 int degree = new Random().nextInt()%30;
67
68 String ch = base.charAt(new Random().nextInt(base.length()))+"";
69
70 g.rotate(degree*Math.PI/180,x,20);//设置旋转角度
71 g.drawString(ch, x, 20);
72 g.rotate(-degree*Math.PI/180,x,20);
73 x+=30;
74 }
75
76 }
77
78 private void drawRandomLine(Graphics g) {
79 g.setColor(Color.GREEN);
80 for (int i = 0; i < 5; i++) {
81 int x1 = new Random().nextInt(WIDTH);
82 int y1 = new Random().nextInt(HEIGHT);
83
84 int x2 = new Random().nextInt(WIDTH);
85 int y2 = new Random().nextInt(HEIGHT);
86
87 g.drawLine(x1, y1, x2, y2);
88 }
89 }
90
91 private void setBorder(Graphics g) {
92
93 g.setColor(Color.BLUE);
94 g.drawRect(1, 1, WIDTH - 2, HEIGHT - 2);
95
96 }
97
98 private void setBackGround(Graphics g) {
99
100 g.setColor(Color.WHITE);
101 g.fillRect(0, 0, WIDTH, HEIGHT);
102
103 }
104
105 public void doPost(HttpServletRequest request, HttpServletResponse response)
106 throws ServletException, IOException {
107
108 }
109
110 }
1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
2 <html>
3 <head>
4 <title>register.html</title>
5
6 </head>
7 <script type="text/javascript">
8 function changeImage(img){
9 img.src = img.src + "?" + new Date().getTime();
10 }
11 </script>
12 <style>
13 </style>
14
15 <body>
16 <form>
17 用户名：
18 <input type="text" name="username">
19 <br />
20 密码：
21 <input type="password" name="password">
22 <br />
23 认证码：
24 <input type="text" name="checkcode" />
25 <img src="/ServletDemo/servlet/ResponseDemo"
26 onclick="changeImage(this)" alt="换一张" style="cursor:hand" />
27 <br />
28 <input type="submit" value="注册" />
29 </form>
30 </body>
31 </html>
输出随机认证码图片
时间： 2024-10-23 17:52:58