Jsp servlet验证码工具类分享

时间：2025-07-03 14:00:02 编辑：袖梨来源：一聚教程网

这篇文章主要为大家分享了Jsp servlet验证码工具类，具有一定的参考价值，感兴趣的小伙伴们可以参考一下

昨晚在csdn看到一位前辈写一个ajax+servlet+jsp验证，顿时心血来潮，在阅读前辈的代码下我亲手体验一下，做了一个验证码生成工具类，以供大家做个参考。

1、添加VeriyCodeUtils类生成验证码图像

package com.servlet;import java.awt.Color; import java.awt.Font; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.OutputStream; import java.util.Random;import javax.imageio.ImageIO;/**** @author hubiao*验证码生成器* 用到API*BufferedImage 创建一个图像*Graphics2D 绘制* fillRect(x,y,width,height);背景* font()字体* drawRect();边框* drawLine();线* drwaString:图像数据*ImageIO 生成图像*/ public class VeriyCodeUtils {/** * @param output 保存验证图像的流 * @return 验证码 */public static String newVeriyCode(OutputStream output){ int width = 90; int height = 40; int codeCount = 5; char[] codeSequence = { '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' };//创建图像对象,8位RGB BufferedImage buffered = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);//通过Crapahices来绘制图像到BufferedImage中 Graphics2D gra = buffered.createGraphics();//设置图片背景：白色 gra.setColor(Color.WHITE); gra.fillRect(0, 0, width, height);//设置字体,字体大小根据图片高度决定 gra.setFont(new Font("Fixedsys",Font.PLAIN,height-2));//设置边框：黑色,1cm gra.setColor(Color.BLACK); gra.drawRect(0, 0, width-1, height-1);//生成10条黑色干扰线 gra.setColor(Color.BLACK); Random ran = new Random(); for(int i = 0; i < 70;i++) {int x = ran.nextInt(255);int y = ran.nextInt(255);int x1 = ran.nextInt(255);int y1 = ran.nextInt(255);gra.drawLine(x, y,x+x1, y+y1);//画直线 } //生成验证码 StringBuffer sb = new StringBuffer(); int r = 0,g = 0,b = 0; for(int i = 0; i < codeCount; i++) {String strRand = String.valueOf(codeSequence[ran.nextInt(codeSequence.length)]);//对每位验证码都生成不同的颜色，增加识别系统难度r = ran.nextInt(255);g = ran.nextInt(255);b = ran.nextInt(255);gra.setColor(new Color(r, g, b));gra.drawString(strRand, (i+1)*13, height-4);sb.append(strRand); } try {ImageIO.write(buffered, "jpeg", output); } catch (Exception e) {throw new RuntimeException(e); }return sb.toString();} }

2、servlet使用验证码

protected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException { //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");//生成验证码图像 String veriyCode = VeriyCodeUtils.newVeriyCode(resp.getOutputStream());//将验证码保存到session中 HttpSession session = req.getSession(); session.setAttribute("validateCode", veriyCode);}

3、JSP页面使用验证码

</head><script type="text/javascript"> function createCode() {var t = new Date().getTime();//防止页面缓存，使用时间搓var srcImg = document.getElementById("srcImg");srcImg.src="/ImgVeifyWeb/vity.do?"+t; }</script><body><h1>${requestScope.code}</h1><img id="srcImg" src="<c:url value="/vity.do"></c:url>" /> #这里使用直接让img访问servlet,通过response响应一个图像流<a href="##" rel="external nofollow" id="codeId" onclick="createCode()">换一张</a><form action="<c:url value="/hello.do"></c:url>" method="post"> <input type="text" name="codeVify"/> <input type="submit" value="提交"/></form></body>

4、校验验证码

protected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException { HttpSession session = req.getSession(); Object validateCode = session.getAttribute("validateCode"); System.out.println(validateCode);String codeVify = req.getParameter("codeVify"); if(codeVify==null || codeVify.equals("")) {req.setAttribute("code","验证证不能为空");req.getRequestDispatcher("/index.jsp").forward(req, resp);return; }else if(!validateCode.toString().equalsIgnoreCase(codeVify)) {req.setAttribute("code","验证证错误");req.getRequestDispatcher("/index.jsp").forward(req, resp);return; } System.out.println("下面开始 做其他业务操作....");}

校验图如下：

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