登录生成随机验证码-蒲公英云

点击创业

验证码生成是单独的一个servlet，通过web.xml进行拦截。

先贴web.xml配置代码，很简单。

[html] view plain copy

/CheckCode
com.wswhr.LoginServer.servlet.CheckCode
/CheckCode
/CheckCode

然后，是这个checkCode的代码。

[java] view plain copy

package com.wswhr.LoginServer.servlet;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
//import cn.com.daxtech.framework.security.UidPwdAuthenticationFilter;
@SuppressWarnings(“serial”)
public class CheckCode extends HttpServlet
{
private static int WIDTH = 60;
private static int HEIGHT = 20;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
HttpSession session = request.getSession();
response.setContentType(“image/jpeg”);
ServletOutputStream sos = response.getOutputStream();
// 设置浏览器不要缓存此图片
response.setHeader(“Pragma”, “No-cache”);
response.setHeader(“Cache-Control”, “no-cache”);
response.setDateHeader(“Expires”, 0);
// 创建内存图象并获得其图形上下文
BufferedImage image = new BufferedImage(WIDTH, HEIGHT,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
// 产生随机的认证码
char[] rands = generateCheckCode();
// 产生图像
drawBackground(g);
drawRands(g, rands);
// 结束图像的绘制过程，完成图像
g.dispose();
// 将图像输出到客户端
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ImageIO.write(image, “JPEG”, bos);
byte[] buf = bos.toByteArray();
response.setContentLength(buf.length);
// 下面的语句也可写成： bos.writeTo(sos);
sos.write(buf);
bos.close();
sos.close();
// 将当前验证码存入到 Session 中
session.setAttribute(“validateCode”, new String(rands));
//session.setAttribute(UidPwdAuthenticationFilter.VALIDATE_CODE, new String(rands));
// 直接使用下面的代码将有问题， Session 对象必须在提交响应前获得
//request.getSession().setAttribute(“check_code”,new String(rands));
}
private char[] generateCheckCode() {
// 定义验证码的字符表
String chars = “2345678abcdefghjkmnprstuwxz”;
char[] rands = new char[4];
for (int i = 0; i < 4; i++) {
int rand = (int) (Math.random() * chars.length());
rands[i] = chars.charAt(rand);
}
return rands;
}
private void drawRands(Graphics g, char[] rands) {
g.setColor(Color.BLACK);
g.setFont(new Font(null, Font.ITALIC | Font.BOLD, 18));
// 在不同的高度上输出验证码的每个字符
g.drawString(“” + rands[0], 1, 17);
g.drawString(“” + rands[1], 16, 15);
g.drawString(“” + rands[2], 31, 18);
g.drawString(“” + rands[3], 46, 16);
// System.out.println(rands);
}
private void drawBackground(Graphics g) {
// 画背景
g.setColor(new Color(0xDCDCDC));
g.fillRect(0, 0, WIDTH, HEIGHT);
// 随机产生 120 个干扰点
for (int i = 0; i < 120; i++) {
int x = (int) (Math.random() * WIDTH);
int y = (int) (Math.random() * HEIGHT);
int red = (int) (Math.random() * 255);
int green = (int) (Math.random() * 255);
int blue = (int) (Math.random() * 255);
g.setColor(new Color(red, green, blue));
g.drawOval(x, y, 1, 0);
}
}
}

最后，是使用验证码的jsp代码，以及JS代码

<label>
    <span>
        <span class="lbl input-icon input-icon-right">
            <input id="validateCode" name="validateCode" type="text" class="span12"
            maxlength="15" placeholder="验证码" />
            <i class="icon-retweet">
            </i>
        </span>
        <span class="lbl">
            <img src="${ctx}/CheckCode" id="yzmPic" οnclick="reloadCheckCode()" style="cursor:pointer;"
            title="点击刷新验证码" />
            <a href="#" οnclick="reloadCheckCode()" data-action="reload">
                <i class="icon-refresh">
                </i>
            </a>
        </span>
    </span>
</label>