第一：login.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!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>用户登录</title>
</head>
<body>
<form action="<c:url value='/welcome.do'/>" method="post">
用户名：<input type="text" name="username"><br/>
密码： <input type="password" name="password"><br/>
<input type="submit" value="提交">
</form>
</body>
</html>
然后在WEB-INFO 下建个pages目录，在里面建两个jsp页面，success.jsp 和 error.jsp