Java生成验证码

 1 import java.awt.*;
 2 import java.awt.image.BufferedImage;
 3 import java.io.*;
 4 import java.util.Random;
 5 import javax.imageio.ImageIO;
 6  
 7 public class ValidationCode {
 8  
 9     // 图形验证码的字符集合，系统将随机从这个字符串中选择一些字符作为验证码
10     private static String codeChars = "%#23456789abcdefghkmnpqrstuvwxyzABCDEFGHKLMNPQRSTUVWXYZ";
11  
12     // 返回一个随机颜色（Color对象）
13     private static Color getRandomColor(int minColor, int maxColor) {
14         Random random = new Random();
15         // 保存minColor最大不会超过255
16         if (minColor > 255)
17             minColor = 255;
18         // 保存minColor最大不会超过255
19         if (maxColor > 255)
20             maxColor = 255;
21         // 获得红色的随机颜色值
22         int red = minColor + random.nextInt(maxColor - minColor);
23         // 获得绿色的随机颜色值
24         int green = minColor + random.nextInt(maxColor - minColor);
25         // 获得蓝色的随机颜色值
26         int blue = minColor + random.nextInt(maxColor - minColor);
27         return new Color(red, green, blue);
28     }
29  
30     protected static void getValidationCode() throws IOException {
31         try {
32             // 获得验证码集合的长度
33             int charsLength = codeChars.length();
34             // 设置图形验证码的长和宽（图形的大小）
35             int width = 90, height = 30;
36             BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
37             Graphics g = image.getGraphics();// 获得用于输出文字的Graphics对象
38             Random random = new Random();
39             g.setColor(getRandomColor(180, 250));// 随机设置要填充的颜色
40             g.fillRect(0, 0, width, height);// 填充图形背景
41             // 设置初始字体
42             g.setFont(new Font("Times New Roman", Font.ITALIC, height));
43             g.setColor(getRandomColor(120, 180));// 随机设置字体颜色
44             // 用于保存最后随机生成的验证码
45             StringBuilder validationCode = new StringBuilder();
46             // 验证码的随机字体
47             String[] fontNames = { "Times New Roman", "Book antiqua", "Arial" };
48             // 随机生成3个到5个验证码
49             for (int i = 0; i < 3 + random.nextInt(3); i++) {
50                 // 随机设置当前验证码的字符的字体
51                 g.setFont(new Font(fontNames[random.nextInt(3)], Font.ITALIC, height));
52                 // 随机获得当前验证码的字符
53                 char codeChar = codeChars.charAt(random.nextInt(charsLength));
54                 validationCode.append(codeChar);
55                 // 随机设置当前验证码字符的颜色
56                 g.setColor(getRandomColor(10, 100));
57                 // 在图形上输出验证码字符，x和y都是随机生成的
58                 g.drawString(String.valueOf(codeChar), 16 * i + random.nextInt(7), height - random.nextInt(6));
59             }
60             File file = new File("d:\\code.png");  
61             ImageIO.write(image, "png", file);  
62             System.out.println(validationCode.toString());
63             //byte[] data = ((DataBufferByte) image.getData().getDataBuffer()).getData();
64             g.dispose();
65         } catch (Exception e) {
66             e.printStackTrace();  
67         }
68     }
69  
70     public static void main(String[] args) throws IOException{
71         getValidationCode();
72     }
73 }