1、登录（login.jsp）
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>登录页面</title>
<style type="text/css">
body{margin: 0;}
#login_div{height: 720px;background-color: darkslategray;padding-top: 30px;}
form{text-align: center;float: right;margin-right: 30px;}
input{ 280px;height: 30px;margin-top: 10px;}
img{ 280px;height: 30px;margin-top: 10px;}
.btn{background-color: #009F95;opacity: 0.7; 280px;}
</style>
</head>
<body>
<div id="login_div">
<form action="Verification.jsp" method="post" >
<div style="font-size: 25px;color: #01AAED;">欢迎登录</div>
<input type="text" name="username" placeholder="请输入账户"/><br>
<input type="password" name="password" placeholder="请输入密码"><br>
<img id="captcha" src="${pageContext.request.contextPath}/captcha" onclick="refresh()"/><br>
<input type="text" name="captcha" placeholder="请输入4位验证码"/><br>
<input id="login" type="submit" value="登录" class="btn"/><br>
<input id="autoLogin" type="submit" value="已登录" class="btn"/><br>
</form>
</div>
<script>
function refresh() {
document.getElementById("captcha").src="${pageContext.request.contextPath}/captcha?"+new Date().getTime();
}
</script>
</body>
</html>
2、验证（Verication.jsp)
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<%
String captcha = request.getParameter("captcha");
String username = request.getParameter("username");
String password = request.getParameter("password");
String realCap = (String) session.getAttribute("captcha");
if(session.getAttribute("username")!=null&&session.getAttribute("password")!=null){
request.getRequestDispatcher("success.jsp").forward(request,response);
}
// 判断是否为空
if(username!=null&&password!=null&&captcha!=null){
//判断账户、密码、验证码是否正确
if(captcha.equalsIgnoreCase(realCap)&&username.equals("zs")&&password.equals("123")){
session.setAttribute("username",username);
session.setAttribute("password",password);
request.getRequestDispatcher("success.jsp").forward(request,response);
}else {
response.sendRedirect("login.jsp");
}
}
%>
</body>
</html>
3、首页（success.jsp）
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<h1 style="text-align: center">
WELCOME:<%=session.getAttribute("username")%>Mr XXX
</h1>
</body>
</html>