這篇文章主要介紹了jsp+ajax實(shí)現(xiàn)的局部刷新較驗(yàn)驗(yàn)證碼,基于onblur事件觸發(fā)較驗(yàn)功能,以實(shí)例形式詳細(xì)的分析了前臺顯示、圖片生成及Ajax動態(tài)驗(yàn)證等詳細(xì)技巧,具有一定參考借鑒價值,需要的朋友可以參考下

本文實(shí)例講述了jsp+ajax實(shí)現(xiàn)的局部刷新較驗(yàn)驗(yàn)證碼(onblur事件觸發(fā)較驗(yàn))。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(dāng)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(chuàng)建XMLHttpRequest
  createXMLHttpRequest();
  var url = "codevalidate.jsp?authcode=" + field.value + "×tamp=" + new Date().getTime();//加時間戳防止緩存重復(fù)
  xmlHttp.open("GET", url, true);
  //方法地址，處理完成后自動調(diào)用，回調(diào)
  xmlHttp.onreadystatechange=function() { //匿名函數(shù)
   if(xmlHttp.readyState == 4) { //Ajax引擎初始化成功
    if (xmlHttp.status == 200) { //http協(xié)議成功
     document.getElementById("divbid").innerHTML =xmlHttp.responseText;
    }else {
     alert("請求失敗，錯誤碼=" + xmlHttp.status);
    }
   }
  };
  //將參數(shù)發(fā)送到Ajax引擎
  xmlHttp.send(null);
 }else {
   div.innerHTML="<div class=\"wrong\">驗(yàn)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(yàn)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(chǎn)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(jī)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(shè)置頁面不緩存  
 response.setHeader("Pragma", "No-cache");  
 response.setHeader("Cache-Control", "no-cache");  
 response.setDateHeader("Expires", 0);  
 // 在內(nèi)存中創(chuàng)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(jī)類  
 Random random = new Random();  
 // 設(shè)定背景色  
 g.setColor(getRandColor(200, 250));  
 g.fillRect(0, 0, width, height);  
 //設(shè)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(jī)產(chǎn)生155條干擾線，使圖象中的認(rèn)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(jī)產(chǎn)生的認(rèn)證碼(4位數(shù)字)  
 String sRand = ""; 
 for (int i = 0; i < 4; i++) {  
  String rand = String.valueOf(random.nextInt(10));  
  sRand += rand;  
  // 將認(rèn)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(diào)用函數(shù)出來的顏色相同，可能是因?yàn)榉N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(rèn)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(tài)驗(yàn)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(yàn)證碼不正確</div>");} 
%>

希望本文所述對大家JSP程序設(shè)計(jì)有所幫助。

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