两组验证码小例子

validateCode.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    <title>两组验证码</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
  </head>

  <body>
    Two Validate Code: <br>
    <img src="vc_1.jsp" />
    <img src="vc_2.jsp" />
  </body>
</html>

vc_1.jsp：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ page import="com.ysx.system.actions.*"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
    <head>
        <title>验证码测试</title>
    </head>

    <body>
        <form name="f1" method="post" action="login.jsp">
            <div>
                <%
                    Yzm a = new Yzm();
                    a.service(request, response);
                    out.clear();
                    out = pageContext.pushBody();
                %>
            </div>
        </form>
    </body>
</html>

vc_2.jsp：

<%@ page
    import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*"%>
<%@ page import="java.io.OutputStream"%>
<%!Color getRandColor(int fc, int bc) {
        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);
    }%>
<%
    try {
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        int width = 60, height = 20;
        BufferedImage image = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
        OutputStream os = response.getOutputStream();
        Graphics g = image.getGraphics();
        Random random = new Random();
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);

        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
        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);
        }
        String sRand = "";
        for (int i = 0; i < 4; i++) {
            String rand = String.valueOf(random.nextInt(10));
            sRand += rand;
            g.setColor(new Color(20 + random.nextInt(110), 20 + random
                    .nextInt(110), 20 + random.nextInt(110)));
            g.drawString(rand, 13 * i + 6, 16);
        }
        session.setAttribute("rand", sRand);
        g.dispose();

        ImageIO.write(image, "JPEG", os);
        os.flush();
        os.close();
        os = null;
        response.flushBuffer();
        out.clear();
        out = pageContext.pushBody();
    } catch (IllegalStateException e) {
        System.out.println(e.getMessage());
        e.printStackTrace();
    }
%>

Yzm.java：

import java.awt.Color;

import java.awt.Font;

import java.awt.Graphics2D;

import java.awt.image.BufferedImage;

import java.util.Random;

import javax.imageio.ImageIO;

import javax.servlet.*;

import javax.servlet.http.*;

public class Yzm extends HttpServlet {

public static final long serialVersionUID = 1L;

// 验证码图片的宽度。

private int width = 60;

// 验证码图片的高度。

private int height = 20;

protected void service(HttpServletRequest req, HttpServletResponse resp)

throws ServletException, java.io.IOException {

BufferedImage buffImg = new BufferedImage(width, height,

BufferedImage.TYPE_INT_RGB);

Graphics2D g = buffImg.createGraphics();

// 创建一个随机数生成器类。

Random random = new Random();

g.setColor(Color.WHITE);

g.fillRect(0, 0, width, height);

// 创建字体，字体的大小应该根据图片的高度来定。

Font font = new Font("Times New Roman", Font.PLAIN, 18);

// 设置字体。

g.setFont(font);

// 画边框。

g.setColor(Color.BLACK);

g.drawRect(0, 0, width - 1, height - 1);

// 随机产生160条干扰线，使图象中的认证码不易被其它程序探测到。

g.setColor(Color.GRAY);

for (int i = 0; i < 10; 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);

}

// randomCode用于保存随机产生的验证码，以便用户登录后进行验证。

StringBuffer randomCode = new StringBuffer();

int red = 0, green = 0, blue = 0;

// 随机产生4位数字的验证码。

for (int i = 0; i < 4; i++) {

// 得到随机产生的验证码数字。

String strRand = String.valueOf(random.nextInt(10));

// 产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同。

red = random.nextInt(200);

green = random.nextInt(200);

blue = random.nextInt(200);

// 产生随机高度 13至height之间

float imght = 0;

while (imght <= 12) {

imght = Float

.parseFloat(String.valueOf(random.nextInt(height)));

}

// 用随机产生的颜色将验证码绘制到图像中。

g.setColor(new Color(red, green, blue));

g.drawString(strRand, 13 * i + 6, imght);

// 将产生的四个随机数组合在一起。

randomCode.append(strRand);

}

// 将四位数字的验证码保存到Session中。

HttpSession session = req.getSession();

session.setAttribute("randomCode", randomCode.toString());

// 禁止图像缓存。

resp.setHeader("Pragma", "no-cache");

resp.setHeader("Cache-Control", "no-cache");

resp.setDateHeader("Expires", 0);

resp.setContentType("image/jpeg");

// 将图像输出到Servlet输出流中。

ServletOutputStream sos = resp.getOutputStream();

ImageIO.write(buffImg, "jpeg", sos);

sos.close();

}

posted @ 2009-09-22 19:45 Jakin.zhou 阅读(149) 评论(0) 收藏举报

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