java生成图片验证码示例代码

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
/*
 * 步骤：
 * 1.画框
 * 2.画背景
 * 3.画字符
 * 4.画干扰线
 */
public final class ImageUtil {
  
 // 验证码字符集
 private static final char[] chars = { 
  '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 
  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 
  'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
 // 字符数量
 private static final int SIZE = 4;
 // 干扰线数量
 private static final int LINES = 5;
 // 宽度
 private static final int WIDTH = 80;
 // 高度
 private static final int HEIGHT = 40;
 // 字体大小
 private static final int FONT_SIZE = 30;
 
 /**
  * 生成随机验证码及图片
  * Object[0]验证码字符串String
  * Object[1]验证码图片 BufferedImage
  */
 public static Object[] createImage() {
  StringBuffer sb = new StringBuffer();
  // 1.创建空白图片
  BufferedImage image = new BufferedImage(
   WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
  // 2.获取图片画笔
  Graphics graphic = image.getGraphics();
  // 3.设置画笔颜色
  graphic.setColor(Color.LIGHT_GRAY);
  // 4.绘制矩形背景
  graphic.fillRect(0, 0, WIDTH, HEIGHT);
  // 5.画随机字符
  Random ran = new Random();
  for (int i = 0; i <SIZE; i++) {
   // 取随机字符索引
   int n = ran.nextInt(chars.length);
   // 设置随机颜色
   graphic.setColor(getRandomColor());
   // 设置字体大小
   graphic.setFont(new Font(
    null, Font.BOLD + Font.ITALIC, FONT_SIZE));
   // 画字符
   graphic.drawString(
    chars[n] + "", i * WIDTH / SIZE, HEIGHT / 2);
   // 记录字符
   sb.append(chars[n]);
  }
  // 6.画干扰线
  for (int i = 0; i < LINES; i++) {
   // 设置随机颜色
   graphic.setColor(getRandomColor());
   // 随机画线
   graphic.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT),
     ran.nextInt(WIDTH), ran.nextInt(HEIGHT));
  }
  // 7.返回验证码和图片
  return new Object[]{sb.toString(), image};
 }
 
 /**
  * 随机取色
  */
 public static Color getRandomColor() {
  Random ran = new Random();
  Color color = new Color(ran.nextInt(256), 
    ran.nextInt(256), ran.nextInt(256));
  return color;
 }
  
 public static void main(String[] args) throws IOException {
  Object[] objs = createImage();
  BufferedImage image = (BufferedImage) objs[1];
  //图片格式可以自定义，java对png图片显示更清楚，输出路径可自定义
  OutputStream os = new FileOutputStream("d:/x.png");
  //注意图片格式与创建格式匹配
  ImageIO.write(image, "png", os);
  os.close();
 }
 
}