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Partial refresh verification code implemented by jsp+ajax (onblur event triggers verification)

高洛峰
高洛峰Original
2017-01-10 11:26:351741browse

The example of this article describes the partial refresh verification code implemented by jsp+ajax (the onblur event triggers the verification). Share it with everyone for your reference, the details are as follows:

Front-end display page:

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?authcode=" + 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 class=\"wrong\">验证码不能为空</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">
  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(&#39;authcode.jsp&#39;)">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>

Generate pictures Page

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 dynamic verification page

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=&#39;right&#39;>√</div>");}
 else{
 out.println("<div class=&#39;wrong&#39;>验证码不正确</div>");}
%>

I hope this article will be helpful to everyone in JSP programming.

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