Java生成验证码

import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Random;
import javax.imageio.ImageIO;

public class ValidationCode {

// 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
private static String codeChars = "%#23456789abcdefghkmnpqrstuvwxyzABCDEFGHKLMNPQRSTUVWXYZ";

// 返回一个随机颜色（Color对象）
private static Color getRandomColor(int minColor, int maxColor) {
Random random = new Random();
// 保存minColor最大不会超过255
if (minColor > 255)
minColor = 255;
// 保存minColor最大不会超过255
if (maxColor > 255)
maxColor = 255;
// 获得红色的随机颜色值
int red = minColor + random.nextInt(maxColor - minColor);
// 获得绿色的随机颜色值
int green = minColor + random.nextInt(maxColor - minColor);
// 获得蓝色的随机颜色值
int blue = minColor + random.nextInt(maxColor - minColor);
return new Color(red, green, blue);
}

protected static void getValidationCode() throws IOException {
try {
// 获得验证码集合的长度
int charsLength = codeChars.length();
// 设置图形验证码的长和宽（图形的大小）
int width = 90, height = 30;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();// 获得用于输出文字的Graphics对象
Random random = new Random();
g.setColor(getRandomColor(180, 250));// 随机设置要填充的颜色
g.fillRect(0, 0, width, height);// 填充图形背景
// 设置初始字体
g.setFont(new Font("Times New Roman", Font.ITALIC, height));
g.setColor(getRandomColor(120, 180));// 随机设置字体颜色
// 用于保存最后随机生成的验证码
StringBuilder validationCode = new StringBuilder();
// 验证码的随机字体
String[] fontNames = { "Times New Roman", "Book antiqua", "Arial" };
// 随机生成3个到5个验证码
for (int i = 0; i < 3 + random.nextInt(3); i++) {
// 随机设置当前验证码的字符的字体
g.setFont(new Font(fontNames[random.nextInt(3)], Font.ITALIC, height));
// 随机获得当前验证码的字符
char codeChar = codeChars.charAt(random.nextInt(charsLength));
validationCode.append(codeChar);
// 随机设置当前验证码字符的颜色
g.setColor(getRandomColor(10, 100));
// 在图形上输出验证码字符，x和y都是随机生成的
g.drawString(String.valueOf(codeChar), 16 * i + random.nextInt(7), height - random.nextInt(6));
}
File file = new File("d:\\code.png");
ImageIO.write(image, "png", file);
System.out.println(validationCode.toString());
//byte[] data = ((DataBufferByte) image.getData().getDataBuffer()).getData();
g.dispose();
} catch (Exception e) {
e.printStackTrace();
}
}

public static void main(String[] args) throws IOException{
getValidationCode();
}
}