登陆用户名和密码判断+验证码验证
省略dao层和service层
1、生成验证码的number.jsp
<%@ page contentType="image/jpeg" language="java" import="java.util.*,java.awt.*,java.awt.image.*,javax.imageio.*" pageEncoding="utf-8"%> ???<%! ?????Color getRandColor(int fc,int bc){ ?????????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-catch"); ?????response.setDateHeader("Expires",0); ???????????//在内存中创建图象 ?????int width = 60; ?????int height = 20; ?????BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); ???????????//创建图象 ?????Graphics g = image.getGraphics(); ?????//生成随机对象 ?????Random random = new Random(); ?????//设置背景色 ?????g.setColor(getRandColor(200,250)); ?????g.fillRect(0,0,width,height); ?????//设置字体 ?????g.setFont(new Font("Tines Nev Roman",Font.PLAIN,18)); ?????//随机产生干扰线 ?????g.setColor(getRandColor(160,200)); ?????for(int i = 0; i < 255; i++){ ?????????int x = random.nextInt(width); ?????????int y = random.nextInt(height); ?????????int xl = random.nextInt(12); ?????????int yl = random.nextInt(12); ?????} ?????//随机产生认证码,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))); ?????????g.drawString(rand,13*i+6,16); ?????} ?????session.setAttribute("rCode",sRand); ?????//图像生效 ?????g.dispose(); ?????//输出图像到页面 ?????ImageIO.write(image,"JPEG",response.getOutputStream()); ?????out.clear(); ?????out = pageContext.pushBody(); ?%> session.setAttribute("rCode",sRand); 这是把生成的验证码放入Session中。便于验证时候获取
2、checkLoginServlet.javapublic void doPost(HttpServletRequest request, HttpServletResponse response) ???????????throws ServletException, IOException { ???????response.setContentType("text/html"); ???????PrintWriter out = response.getWriter(); ???????String username = request.getParameter("username"); ???????String password = request.getParameter("password"); ???????String code =request.getParameter("ucode"); ???????UserService userService=new UserServiceImpl(); ???????String rCode =(String) request.getSession().getAttribute("rCode"); ???????System.out.println("username=============="+username); ???????//用户名是否存在 ???????if(!userService.checkUsername(username)){ ???????????out.write("unregistered"); ???????}else if(!code.equals(rCode)){ ???????????out.write("codeerror"); ???????}else if(!userService.checkIsAdmin(username)){ ???????????out.write("noadmin"); ???????}else { ???????????????????//用户名是否被锁 ???????????if(!userService.checkUsernameStatus(username)){ ???????????????out.write("forzen"); ???????????????} ???????????????????????//用户名和密码是否正确 ???????????if(!userService.checkLogin(username, password)){ ???????????????out.write("fail"); ???????????}else{ ???????????????out.write("success"); ???????????} ???????????????????????????????} ???????????????????????//判断用户名是否存在，不存在，存在后再判断p ???????????}3、jsp页面 login.jsp
<%@ page language="java" contentType="text/html; charset=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" /> ???<meta http-equiv="X-UA-Compatible" content="IE=edge"> ???<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" /> ???<meta name="renderer" content="webkit"> ???<title>登录</title> ?????<link rel="stylesheet" href="../css/pintuer.css"> ???<link rel="stylesheet" href="../css/admin.css"> ???<script src="../js/jquery.js"></script> ???<script src="../js/pintuer.js"></script> ????????<script type="text/javascript"> ???$(document).ready(function(){ ???????????????$("#btnLogin").click(function(){ ???????????var username = $("#username").val(); ???????????var password = $("#password").val(); ???????????var ucode = $("#code").val(); ???????????if(username =="" || password==""){ ???????????????alert("用户名和密码不能为空"); ???????????}else{ ???????????????$.ajax({ ???????????????????type:"POST", ???????????????????url:"<%=request.getContextPath()%>/CheckLoginServlet", ???????????????????data:{ ???????????????????????"username":username, ???????????????????????"password":password, ???????????????????????"ucode":ucode ???????????????????}, ???????????????????contentType:"application/x-www-form-urlencoded", ???????????????????success:function(msg){ ???????????????????????if(msg=="unregistered"){ ???????????????????????????alert("对不起，该用户未注册"); ???????????????????????} ???????????????????????if(msg=="forzen"){ ???????????????????????????alert("对不起，该用户已被锁"); ???????????????????????} ???????????????????????if(msg="noadmin"){ ???????????????????????????alert("对不起，你没有管理员权限"); ???????????????????????} ???????????????????????if(msg=="fail"){ ???????????????????????????alert("对不起，密码错误"); ???????????????????????} ???????????????????????if(msg =="codeerror"){ ???????????????????????????alert("验证码错误"); ???????????????????????} ???????????????????????????????????????????????if(msg=="success"){ ???????????????????????????parent.document.location.href="<%=request.getContextPath()%>/admin/index.jsp"; ???????????????????????} ???????????????????????????????????????????????}, ???????????????????????????????}); ???????????????????????} ???????????return false; ???????????????????????????????}); ???????});</script></head><body> <div class="bg"></div><div class="container"> ???<div class="line bouncein"> ???????<div class="xs6 xm4 xs3-move xm4-move"> ???????????<div style="height:150px;"></div> ???????????<div class="media media-y margin-big-bottom"> ??????????????????????</div> ????????????????????<form id="form1"> ???????????<div class="panel loginbox"> ???????????????<div class="text-center margin-big padding-big-top"><h1>后台管理中心</h1></div> ???????????????<div class="panel-body" style="padding:30px; padding-bottom:10px; padding-top:10px;"> ???????????????????<div class="form-group"> ???????????????????????<div class="field field-icon-right"> ???????????????????????????<input id="username" type="text" class="input input-big" name="name" placeholder="登录账号" data-validate="required:请填写账号" /> ???????????????????????????<span class="icon icon-user margin-small"></span> ???????????????????????</div> ???????????????????</div> ???????????????????<div class="form-group"> ???????????????????????<div class="field field-icon-right"> ???????????????????????????<input type="password" id="password" class="input input-big" name="password" placeholder="登录密码" data-validate="required:请填写密码" /> ???????????????????????????<span class="icon icon-key margin-small"></span> ???????????????????????</div> ???????????????????</div> ???????????????????<div class="form-group"> ???????????????????????<div class="field"> ???????????????????????????<input type="text" class="input input-big" id="code" name="code" placeholder="填写右侧的验证码" data-validate="required:请填写右侧的验证码" /> ??????????????????????????<img src="number.jsp" id="safeCode"/><a id="changeCode" href="#">看不清，换一张</a> ???????????????????????????????????????????????????????????????????????????</div> ???????????????????</div> ???????????????</div> ???????????????<div style="padding:30px;"><input type="submit" id="btnLogin" class="button button-block bg-main text-big input-big" value="登录"></div> ???????????</div> ???????????</form> ?????????????????</div> ???</div></div></body></html>比较简单的4位数字图片验证码。
ajax-登陆+验证码（转载）
原文地址：http://www.cnblogs.com/HongDunLaoGui/p/7780742.html