关于图片的验证码

原创
2012/01/06 11:24
阅读数 160

package photo;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.util.Random;

import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;


public class ImageCodeAction  {
 private InputStream input;

 private static int WIDTH = 300;

 private static int HEIGHT = 100;

 private static int NUM = 4;

 private static char[] seq = { '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', '0', '1', '2', '3', '4', '5', '6', '7', '8',
   '9' };

 public String execute() {
  byte[] image = randomImage();
  input = new ByteArrayInputStream(image);
  return "success";
 }

 /**
  *
  * @return
  */
 private byte[] randomImage() {
  Random r = new Random();

  // 图片的内存映像
  BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
    BufferedImage.TYPE_INT_RGB);

  // 获得画笔对象
  Graphics g = image.getGraphics();
  g.setColor(randomColor(r));
  g.fillRect(0, 0, WIDTH, HEIGHT);
  g.setColor(new Color(0, 0, 0));

  // 用于存储随机生成的验证码
  StringBuffer number = new StringBuffer();

  // 绘制验证码
  for (int i = 0; i < NUM; i++) {
   g.setColor(randomColor(r));
   int h = (int) ((HEIGHT * 60 / 100) * r.nextDouble() + (HEIGHT * 30 / 100));
   g.setFont(new Font(null, Font.BOLD | Font.ITALIC, h));
   String ch = String.valueOf(seq[r.nextInt(seq.length)]);
   number.append(ch);
   g.drawString(ch, i * WIDTH / NUM * 90 / 100, h);
  }

  session.put("code", number.toString());
  System.out.println(number.toString());

  // 绘制干扰线
  for (int i = 0; i <= 12; i++) {
   g.setColor(randomColor(r));
   g.drawLine(r.nextInt(WIDTH), r.nextInt(HEIGHT), r.nextInt(WIDTH), r
     .nextInt(HEIGHT));

  }

  ByteArrayOutputStream os = new ByteArrayOutputStream();

  JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(os);

  // 把BufferedImage对象中的图像信息编码后
  // 向创建该对象(encoder)时指定的输出流输出
  try {
   encoder.encode(image);
   return os.toByteArray();
  } catch (Exception e) {
   throw new RuntimeException(e);
  }
 }

 private Color randomColor(Random r) {
  return new Color(r.nextInt(255), r.nextInt(255), r.nextInt(255));
 }

 public InputStream getInput() {
  return input;
 }

 public void setInput(InputStream input) {
  this.input = input;
 }

}

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