如何在系统中实现验证码的功能

zhaoweihappy 2008-12-24 12:55:59
如何在系统中实现验证码的功能
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zhaoweihappy 2008-12-24
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谢谢各位老师的指导,祝大家圣诞节快乐
fys249931556 2008-12-24
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3.验证验证码:num.jsp

<%@ page autoFlush="false" import="java.util.*,java.awt.*,java.awt.image.*,com.sun.image.codec.jpeg.*,java.util.*" %>

<%
//set Chinese Char
//Cody by JarryLi@gmail.com;
//homepage:jiarry.126.com
request.setCharacterEncoding("GBK");
response.setCharacterEncoding("GBK");
response.setContentType("text/html; charset=GBK");
%>
<%
String chose="0123456789";
//abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ
char display[]={'0',' ','0',' ','0',' ','0'},ran[]={'0','0','0','0'},temp;

Random rand=new Random();

for(int i=0;i<4;i++)
{

temp=chose.charAt(rand.nextInt(chose.length()));

display[i*2]=temp;

ran[i]=temp;
}

String random=String.valueOf(display);

session.setAttribute("random",String.valueOf(ran));
%>
<%

out.clear();
response.setContentType("image/jpeg");
response.addHeader("pragma","NO-cache");
response.addHeader("Cache-Control","no-cache");
response.addDateHeader("Expries",0);
int width=80, height=30;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
//beijingse
g.setColor(Color.GREEN);
g.fillRect(0, 0, width, height);
//zitise
g.setColor(Color.RED);
Font font=new Font("Arial",Font.PLAIN,20);
g.setFont(font);
//g.drawString(random,5,14);
g.drawString(random,5,20);
g.dispose();
ServletOutputStream outStream = response.getOutputStream();
JPEGImageEncoder encoder =JPEGCodec.createJPEGEncoder(outStream);
encoder.encode(image);
outStream.close();
out.clear();
out = pageContext.pushBody();

%>


4.登录页面:img.jsp

<%@ page contentType="text/html; charset=GBK" language="java" import="java.sql.*" errorPage="" pageEncoding="GBK"%>
<%
//set Chinese Char
//Cody by JarryLi@gmail.com;
//homepage:jiarry.126.com
request.setCharacterEncoding("GBK");
response.setCharacterEncoding("GBK");
response.setContentType("text/html; charset=GBK");
%>
<html>
<head>
<title>图片验证</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<script src="net.js"></script>
</head>

<body>
AJAX(无刷新及时提示)验证码实例!cody by jarry
<hr>
<%
String num=request.getParameter("num");
String random=(String)session.getAttribute("random");
String name=request.getParameter("name");
if(num!=null&&random!=null&&name!=null)
{
if(num.equals(random))
{
out.println("<font style=\"color:green;font-weight:bold\">恭喜您,验证码输入成功,这里是提交结果页面,可以写入数据库了!</font> <a href=\"img.jsp\">返回再测试</a><br>");
out.println("您的名字是:"+name);
out.println("<br>");
out.println("您输入的是:"+num);
out.println("验证码是:"+random);
out.println("</body>");
return;//javascript:history.go(-1)
}
}
%>
<script type="text/javascript">
var times=0;
function subform(){
var gtext=this.req.responseText;
alert(gtext);
var info=document.getElementById("info");
if(gtext.indexOf("validate_successful")!=-1){
//info.innerHTML="<font color=green>验证码通过</font>";
document.forms["myform"].submit();
//当得到的值表示合法,则验证码通过。
}else{
times++;
if(times>=3){//如果连接3次输入错误,则重载图片,可以防止作弊和用户看不清图片;
info.innerHTML="接连3次输入错误。更新验证码,请重新输入";
document.forms["myform"].num.value="";
show(document.getElementById('random'));
times=0;
}else{
info.innerHTML="第"+times+"次验证码错误,请注意区分大小写 ";
}
document.forms["myform"].num.select();
}

}
function validata(obj){
var enter=true;
var info=document.getElementById("info");
var msg="";
if(obj.name.value.match(/^\s*$/g)){//如果未输入名字,提示
msg+="请输入您的姓名<br>";enter=false
}
if(obj.num.value.match(/^\s*$/g)){//如果未输入验证码,提示
msg+="请输入验证码<br>";enter=false
}
if(enter==false){
info.innerHTML=msg;
return false;
}
// var url="num.jsp?num="+obj.num.value;
// new net.ContentLoader(url,subform,"","get",null,null);

var url="num.jsp?num="+obj.num.value;
//function(url,on_load,on_error,method,params,contentType)
//new net.ContentLoader(scriptUrl,alertContents,"","GET","count="+count);
new net.ContentLoader(url,subform,null,"GET","num="+obj.num.value,null);

return false;
}
function show(o){
//重载验证码
var timenow = new Date().getTime();
o.src="random.jsp?d="+timenow;
/*
//超时执行;
setTimeout(function(){
o.src="random.jsp?d="+timenow;
}
,20);
*/
}
</script>
<form action="ok.jsp" name="myform" method="post" onsubmit="return validata(this);">
您的姓名:<input type="text" name="name" size=10> (为了更好地说明此例,特加姓名一项)<br>
验 证 码:<input type="text" name="num" size=10 maxlength="4"> <img src="random.jsp" id="random" align="" valign="absmiddle" hspace="5"> <a href="javascript:show(document.getElementById('random'))">验证码看不清</a><br>
<br> <input type="submit" value=" 提交 "><br>
<div id=info style="color:red;padding:10px;font-size:12px;"></div>
</form>
<hr>
说明:ajax验证</body>
</html>


fys249931556 2008-12-24
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给你贴个ajax的验证码验证:4个文件。
1.一个JS文件 net.js

/* namespacing object */
var net=new Object();

net.READY_STATE_UNINITIALIZED=0;
net.READY_STATE_LOADING=1;
net.READY_STATE_LOADED=2;
net.READY_STATE_INTERACTIVE=3;
net.READY_STATE_COMPLETE=4;
/*--- content loader object for cross-browser requests ---*/
net.ContentLoader=function(url,on_load,on_error,method,params,contentType){
this.req=null;
this.on_load=on_load;
this.on_error=(on_error) ? on_error : this.defaultError;
this.loadXMLDoc(url,method,params,contentType);
}
net.ContentLoader.prototype.loadXMLDoc=function(url,method,params,contentType){
if (!method)
{
method="GET";
}
if (!contentType && method=="POST")
{
contentType='application/x-www-form-urlencoded';
}
if (window.XMLHttpRequest)
{
this.req=new XMLHttpRequest();
}
else if (window.ActiveXObject)
{
//add try catch;
try {
this.req = new ActiveXObject("Msxml2.XMLHTTP");
}catch (e1){
try {
this.req = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e2){
}
}
//
//this.req=new ActiveXObject("Microsoft.XMLHTTP");
}
if (this.req)
{
try
{
var loader=this;
this.req.onreadystatechange=function()
{
net.ContentLoader.onReadyState.call(loader);
}
this.req.open(method,url,true);
if (contentType)
{
this.req.setRequestHeader('Content-Type', contentType);
}
this.req.send(params);
}
catch (err)
{
this.on_error.call(this);
}
}
}
net.ContentLoader.onReadyState=function(){
var req=this.req;
var ready=req.readyState;
if (ready==net.READY_STATE_COMPLETE){
var httpStatus=req.status;
if (httpStatus==200 || httpStatus==0){
this.on_load.call(this);
}else{
this.on_error.call(this);
}
}
}
net.ContentLoader.prototype.defaultError=function(){
alert("error fetching data!"
+"\n\nreadyState:"+this.req.readyState
+"\nstatus: "+this.req.status
+"\nheaders: "+this.req.getAllResponseHeaders());
}



2.生成随机验证码的文件 random.jsp

<%@ page autoFlush="false" import="java.util.*,java.awt.*,java.awt.image.*,com.sun.image.codec.jpeg.*,java.util.*" %>

<%
//set Chinese Char
//Cody by JarryLi@gmail.com;
//homepage:jiarry.126.com
request.setCharacterEncoding("GBK");
response.setCharacterEncoding("GBK");
response.setContentType("text/html; charset=GBK");
%>
<%
String chose="0123456789";
//abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ
char display[]={'0',' ','0',' ','0',' ','0'},ran[]={'0','0','0','0'},temp;

Random rand=new Random();

for(int i=0;i<4;i++)
{

temp=chose.charAt(rand.nextInt(chose.length()));

display[i*2]=temp;

ran[i]=temp;
}

String random=String.valueOf(display);

session.setAttribute("random",String.valueOf(ran));
%>
<%

out.clear();
response.setContentType("image/jpeg");
response.addHeader("pragma","NO-cache");
response.addHeader("Cache-Control","no-cache");
response.addDateHeader("Expries",0);
int width=80, height=30;
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
//beijingse
g.setColor(Color.GREEN);
g.fillRect(0, 0, width, height);
//zitise
g.setColor(Color.RED);
Font font=new Font("Arial",Font.PLAIN,20);
g.setFont(font);
//g.drawString(random,5,14);
g.drawString(random,5,20);
g.dispose();
ServletOutputStream outStream = response.getOutputStream();
JPEGImageEncoder encoder =JPEGCodec.createJPEGEncoder(outStream);
encoder.encode(image);
outStream.close();
out.clear();
out = pageContext.pushBody();

%>


ladofwind 2008-12-24
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随机生成一个串,然后存在用户的session里,用户再次提交先对比串一致否

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