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 }
