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;
}
}