Java实现验证码图片 


这样的实现方式对JDK版本有要求。
 1 package edu.cloud.editmap.utils;
 2 
 3 import java.awt.Color;
 4 import java.awt.Font;
 5 import java.awt.Graphics2D;
 6 import java.awt.image.BufferedImage;
 7 import java.io.IOException;
 8 import java.util.Random;
 9 
10 import javax.servlet.ServletOutputStream;
11 import javax.servlet.http.HttpServletRequest;
12 import javax.servlet.http.HttpServletResponse;
13 
14 import com.sun.image.codec.jpeg.JPEGCodec;
15 import com.sun.image.codec.jpeg.JPEGImageEncoder;
16 
17 public class IdentityCode {
18     private static final long serialVersionUID = -479885884254942306L;
19 
20     public static final char[] CHARS = { '2', '3', '4', '5', '6', '7', '8',
21             '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M',
22             'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
23 
24     public static Random random = new Random();
25 
26     public static String getRandomString() {
27         StringBuffer buffer = new StringBuffer();
28         for (int i = 0; i < 4; i++) {
29             buffer.append(CHARS[random.nextInt(CHARS.length)]);
30         }
31         return buffer.toString();
32     }
33 
34     public static Color getRandomColor() {
35         return new Color(random.nextInt(255), random.nextInt(255), random
36                 .nextInt(255));
37     }
38 
39     public static Color getReverseColor(Color c) {
40         return new Color(255 - c.getRed(), 255 - c.getGreen(), 255 - c
41                 .getBlue());
42     }
43 
44     public static void createImage(HttpServletResponse response,HttpServletRequest request){
45 
46 
47         response.setContentType("image/jpeg");
48         
49         String randomString = getRandomString();
50         System.out.println(randomString);
51         
52         request.getSession().setAttribute("indentity_code", randomString);
53         
54         int width = 100;
55         int height = 30;
56 
57         Color color = getRandomColor();
58         Color reverse = getReverseColor(color);
59 
60         BufferedImage bi = new BufferedImage(width, height,
61                 BufferedImage.TYPE_INT_RGB);
62         Graphics2D g = bi.createGraphics();
63         g.setFont(new Font(Font.SANS_SERIF, Font.BOLD, 16));
64         g.setColor(color);
65         g.fillRect(0, 0, width, height);
66         g.setColor(reverse);
67         g.drawString(randomString, 18, 20);
68         for (int i = 0, n = random.nextInt(100); i < n; i++) {
69             g.drawRect(random.nextInt(width), random.nextInt(height), 1, 1);
70         }
71         
72         // 转成JPEG格式
73         try {
74             
75             ServletOutputStream out = response.getOutputStream();
76             JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
77             encoder.encode(bi);
78             out.flush();
79             
80         } catch (IOException e) {
81             e.printStackTrace();
82         }
83         
84     }
85 
86 }

 

posted @ 2015-06-11 10:59  helingfeng  阅读(240)  评论(0)    收藏  举报