本文實例講述了jsp+ajax實現的局部刷新較驗驗證碼(onblur事件觸發較驗)。分享給大家供大家參考，具體如下：
前臺顯示頁面:
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>修改個人信息</title><script>function createXMLHttpRequest() { //表示當前瀏覽器不是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) { //創建XMLHttpRequest createXMLHttpRequest(); var url = "codevalidate.jsp?authcode=" + field.value + "×tamp=" + new Date().getTime();//加時間戳防止緩存重復 xmlHttp.open("GET", url, true); //方法地址，處理完成后自動調用，回調 xmlHttp.onreadystatechange=function() { //匿名函數 if(xmlHttp.readyState == 4) { //Ajax引擎初始化成功 if (xmlHttp.status == 200) { //http協議成功 document.getElementById("divbid").innerHTML =xmlHttp.responseText; }else { alert("請求失敗，錯誤碼=" + xmlHttp.status); } } }; //將參數發送到Ajax引擎 xmlHttp.send(null); }else { div.innerHTML="<div class=/"wrong/">驗證碼不能為空</div>" }}function reloadImage(imgurl){ var getimagecode=document.getElementById("codeimg"); getimagecode.src= imgurl + "?id=" + Math.random(); var code=<%=session.getAttribute("code")%>; alert(code)}</script></head><body><form action="authcode.jsp" method="post" name="loginform"> 輸入驗證碼：<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 + "?id=" + Math.random(); var code=<%=session.getAttribute("code")%>; alert(code)}</script></body></html>產生圖片頁面
authcode.jsp
<%@ page contentType="image/JPEG" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" pageEncoding="GBK"%> <%!Color getRandColor(int fc, int bc) {//給定范圍獲得隨機顏色 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); }%> <% //設置頁面不緩存 response.setHeader("Pragma", "No-cache"); response.setHeader("Cache-Control", "no-cache"); response.setDateHeader("Expires", 0); // 在內存中創建圖象 int width = 60, height = 20; BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 獲取圖形上下文 Graphics g = image.getGraphics(); //生成隨機類 Random random = new Random(); // 設定背景色 g.setColor(getRandColor(200, 250)); g.fillRect(0, 0, width, height); //設定字體 g.setFont(new Font("Times New Roman", Font.PLAIN, 18)); //畫邊框 //g.setColor(new Color()); //g.drawRect(0,0,width-1,height-1); // 隨機產生155條干擾線，使圖象中的認證碼不易被其它程序探測到 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); } // 取隨機產生的認證碼(4位數字) String sRand = ""; for (int i = 0; i < 4; i++) { String rand = String.valueOf(random.nextInt(10)); sRand += rand; // 將認證碼顯示到圖象中 g.setColor(new Color(20 + random.nextInt(110), 20 + random .nextInt(110), 20 + random.nextInt(110)));//調用函數出來的顏色相同，可能是因為種子太接近，所以只能直接生成 g.drawString(rand, 13 * i + 6, 16); System.out.println(rand); } // 將認證碼存入SESSION session.setAttribute("code", sRand); // 圖象生效 g.dispose(); // 輸出圖象到頁面 ImageIO.write(image, "JPEG", response.getOutputStream()); %>ajax動態驗證頁面
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 class='right'>√</div>");} else{ out.println("<div class='wrong'>驗證碼不正確</div>");} %>希望本文所述對大家JSP程序設計有所幫助。
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