本文实例讲述了jsp+ajax实现的局部刷新较验验证码(onblur事件触发较验)。分享给大家供大家参考，具体如下：
前台显示页面:
welcome.jsp
<%@ page language="java" contentType="text/html; utf-8" pageEncoding="utf-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>修改个人信息</title> <script> function createXMLHttpRequest() { //表示当前浏览器不是ie,如ns,firefox if(window.XMLHttpRequest) { xmlHttp = new XMLHttpRequest(); } else if (window.ActiveXObject) { xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); } } function validate(field) { var div=document.getElementById("divbid"); // var reg=/[^A-Za-z0-9_]{7,10}/g; if (field.value.length != 0) { //创建XMLHttpRequest createXMLHttpRequest(); var url = "codevalidate.jsp" + field.value + "×tamp=" + new Date().getTime();//加时间戳防止缓存重复 xmlHttp.open("GET", url, true); //方法地址，处理完成后自动调用，回调 xmlHttp.onreadystatechange=function() { //匿名函数 if(xmlHttp.readyState == 4) { //Ajax引擎初始化成功 if (xmlHttp.status == 200) { //http协议成功 document.getElementById("divbid").innerHTML =xmlHttp.responseText; }else { alert("请求失败，错误码=" + xmlHttp.status); } } }; //将参数发送到Ajax引擎 xmlHttp.send(null); }else { div.innerHTML="<div>验证码不能为空</div>" } } function reloadImage(imgurl){ var getimagecode=document.getElementById("codeimg"); getimagecode.src= imgurl + "" + Math.random(); var code=<%=session.getAttribute("code")%>; alert(code) } </script> </head> <body> <form action="authcode.jsp" method="post" name="loginform"> 输入验证码：<input type="text" name="authcode" id="authcode" maxlength="4" size="10" onblur="validate(this)" ><span id="divbid"></span> <img id="codeimg" name="codeimg" border=0 src="authcode.jsp"> <a href="javascript:reloadImage('authcode.jsp')">看不清</a><br/> </form> <script language="javascript" type="text/javascript"> function reloadImage(imgurl){ var getimagecode=document.getElementById("codeimg"); getimagecode.src= imgurl + "" + Math.random(); var code=<%=session.getAttribute("code")%>; alert(code) } </script> </body> </html>
产生图片页面
authcode.jsp
<%@ page contentType="image/JPEG" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" pageEncoding="GBK"%> <%!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); }%> <% //设置页面不缓存 response.setHeader("Pragma", "No-cache"); response.setHeader("Cache-Control", "no-cache"); response.setDateHeader("Expires", 0); // 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 < 100; 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 sRand = ""; 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); System.out.println(rand); } // 将认证码存入SESSION session.setAttribute("code", sRand); // 图象生效 g.dispose(); // 输出图象到页面 ImageIO.write(image, "JPEG", response.getOutputStream()); %>
ajax动态验证页面
codevalidate.jsp
<%@ page language="java" import="java.util.*,java.util.*,java.text.*,com.neusoft.xkxt.dao.*,com.neusoft.xkxt.bean.*,com.neusoft.xkxt.util.*" pageEncoding="UTF-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <% String authcode=request.getParameter("authcode"); String code=(String)session.getAttribute("code"); if(authcode.equals(code)){ out.println("<div>√</div>");} else{ out.println("<div>验证码不正确</div>");} %>
希望本文所述对大家JSP程序设计有所帮助。
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