昨晚在csdn看到一位前辈写一个ajax+servlet+jsp验证，即刻心血来潮，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东西类，以供各人做个参考。
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 建设一个图像 * Graphics2D 绘制 * fillRect(x,y,width,height);配景 * font()字体 * drawRect();边框 * drawLine();线 * drwaString:图像数据 * ImageIO 生成图像 */ public class VeriyCodeUtils { /** * @param output 生存验证图像的流 * @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' }; //建设图像工具,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(); //配置图片配景：白色 gra.setColor(Color.WHITE); gra.fillRect(0, 0, width, height); //配置字体,字体巨细按照图片高度抉择 gra.setFont(new Font("Fixedsys",Font.PLAIN,height-2)); //配置边框：玄色,1cm gra.setColor(Color.BLACK); gra.drawRect(0, 0, width-1, height-1); //生成10条玄色滋扰线 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差异的颜色，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利用验证码
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //克制图像缓存 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()); //将验证码生存到session中 HttpSession session = req.getSession(); session.setAttribute("validateCode", veriyCode); }
3、JSP页面利用验证码
</head> <script type="text/javascript"> function createCode() { var t = new Date().getTime();//防备页面缓存，利用时间搓 var srcImg = document.getElementById("srcImg"); srcImg.src="/ImgVeifyWeb/vity.do?"+t; } </script> <body> <h1>${requestScope.code}</h1> <img src="<c:url value="/vity.do"></c:url>" /> #这里利用直接让img会见servlet,通过response响应一个图像流 <a href="##">换一张</a> <form action="<c:url value="/hello.do"></c:url>" method="post"> <input type="text"/> <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 做其他业务操纵...."); }
校验图如下：
