jsp中随机数字验证码的实现方法

package com.lanyotech.demo.pss.web;

import java.awt.image.BufferedImage;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;

import com.lanyotech.demo.pss.service.ImageCode;

public class RandomImgCodeAction extends Action {

 @Override
 public ActionForward execute(ActionMapping mapping, ActionForm form,
   HttpServletRequest request, HttpServletResponse response)
   throws Exception {
  int number = 0;
  //number = CommUtil.null2Int(form.get("number"));
  int max = 0;
  //max = CommUtil.null2Int(form.get("max"));
  response.setContentType("image/jpeg");
  ImageCode image = new ImageCode();
  response.setHeader("Pragma", "No-cache");
  response.setHeader("Cache-Control", "no-cache");
  response.setDateHeader("Expires", 0);
  try {
   // 输出图象到页面
   BufferedImage img = null;
   if (number != 0) {
    if (max != 0) {
     img = image.creatImage3D(number, max);
    } else {
     img = image.creatImage(number);
    }
   } else {
    img = image.creatImage();
    request.getSession().setAttribute("rand",
      image.getSRand());

   }
   ImageIO.write(img, "JPEG", response.getOutputStream());
   response.getOutputStream().flush();
   response.getOutputStream().close();
  } catch (Exception e) {
   System.out.println("错误:" + e);
  }
  return null;
 }

}

 

 

 

 

 

 

package com.lanyotech.demo.pss.service;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;

public class ImageCode {

 public String sRand = "";

 public Color getRandColor(int fc, int bc) {// 给定范围获得随机颜色
  Random random = new Random();
  if (fc > 255)
   fc = 255;
  if (bc > 255)
   bc = 255;
  int r = fc + random.nextInt(bc - fc);
  int g = fc + random.nextInt(bc - fc);
  int b = fc + random.nextInt(bc - fc);
  return new Color(r, g, b);
 }

 public BufferedImage creatImage() {
  // 在内存中创建图象
  int width = 60, height = 20;
  BufferedImage image = new BufferedImage(width, height,
    BufferedImage.TYPE_INT_RGB);
  // 获取图形上下文
  Graphics g = image.getGraphics();
  // 生成随机类
  Random random = new Random();
  // 设定背景色
  g.setColor(getRandColor(200, 250));
  g.fillRect(0, 0, width, height);
  // 设定字体
  g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
  // 画边框
  // g.setColor(new Color());
  // g.drawRect(0,0,width-1,height-1);
  // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
  g.setColor(getRandColor(160, 200));
  for (int i = 0; i < 155; i++) {
   int x = random.nextInt(width);
   int y = random.nextInt(height);
   int xl = random.nextInt(12);
   int yl = random.nextInt(12);
   g.drawLine(x, y, x + xl, y + yl);
  }
  // 取随机产生的认证码(4位数字)
  // String rand = request.getParameter("rand");
  // rand = rand.substring(0,rand.indexOf("."));
  for (int i = 0; i < 4; i++) {
   String rand = String.valueOf(random.nextInt(10));
   sRand += rand;
   // 将认证码显示到图象中
   g.setColor(new Color(20 + random.nextInt(110), 20 + random
     .nextInt(110), 20 + random.nextInt(110)));// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
   g.drawString(rand, 13 * i + 6, 16);
  }
  // 图象生效
  g.dispose();
  return image;
 }

 /**
  * @return Returns the sRand.
  */
 public String getSRand() {
  return sRand;
 }

 public BufferedImage creatImage(int number) {
  // 在内存中创建图象
  String num = String.valueOf(number);
  char[] vs = num.toCharArray();

  int width = vs.length * 60 / 4, height = 18;
  BufferedImage image = new BufferedImage(width, height,
    BufferedImage.TYPE_INT_RGB);
  // 获取图形上下文
  Graphics g = image.getGraphics();
  // 生成随机类
  Random random = new Random();
  // 设定背景色
  g.setColor(Color.WHITE);
  g.fillRect(0, 0, width, height);
  // 设定字体
  g.setFont(new Font("Impact", Font.PLAIN, 14));
  // 画边框
  // g.setColor(new Color());
  // g.drawRect(0,0,width-1,height-1);
  // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到
  /*
   * g.setColor(getRandColor(160, 200)); for (int i = 0; i < 155; i++) {
   * int x = random.nextInt(width); int y = random.nextInt(height); int xl =
   * random.nextInt(12); int yl = random.nextInt(12); g.drawLine(x, y, x +
   * xl, y + yl); }
   */
  // 取随机产生的认证码(4位数字)
  // String rand = request.getParameter("rand");
  // rand = rand.substring(0,rand.indexOf("."));
  for (int i = 0; i < vs.length; i++) {
   String rand = String.valueOf(vs[i]);
   sRand += rand;
   // 将认证码显示到图象中
   g.setColor(new Color(20 + random.nextInt(110), 20 + random
     .nextInt(110), 20 + random.nextInt(110)));// 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成
   g.drawString(rand, 13 * i + 6, 16);

  }
  // 图象生效
  g.dispose();
  return image;
 }

 public BufferedImage creatImage3D(int number, int max) {
  // 在内存中创建图象
  int width = 60, height = 10;
  int x = number * width / max;
  System.out.println(x);
  BufferedImage image = new BufferedImage(x, height,
    BufferedImage.TYPE_INT_RGB);
  // 获取图形上下文

  Graphics g = image.getGraphics();
  // g.fillRect(0, 0, width, height);

  g.setColor(this.getRandColor(100, 200));
  g.draw3DRect(0, 0, x, height, true);
  g.fill3DRect(0, 0, x, height, true);
  // 图象生效
  g.dispose();
  return image;
 }
}