一.代码如下:
1.登录页面：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">
<title>Insert title here</title>
</head>
<body>
<form action="login.jsp" method="post">
用户名：<input type "text" name="uname"/><br/>
密 码:
<input type="password" name="upass" /><br/>
<input type="submit" value="登录"/>
<input type="reset" value="重置"/>
</form>
<%//默认的账号为：muzhi ，密码为：xiaoganrenye
String name=request.getParameter("uname");
String password=request.getParameter("upass");
if(!(name==null||"".equals(name)||password==null||"".equals(password))){
if("muzhi".equals(name)&&"xiaoganrenye".equals(password)){
response.setHeader("refresh","2;URL=welcome.jsp");//定时跳转到欢迎页面
session.setAttribute("userid",name);
%>
<h3>用户登录成功，两秒后跳转到欢迎页</h3>
<h3>如果没有跳转，请按<a href="welcome.jsp">跳转</a></h3>
<%}else{ %>
<h3>错误的用户名或密码！！</h3>
<%
}
}
%>
</body>
</html>
2.欢迎页面：
<%@ 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">
<title>Insert title here</title>
</head>
<body>
<%
if(session.getAttribute("userid")!=null){
%>
<h3>欢迎<%=session.getAttribute("userid") %>光临本系统，<a href="logout.jsp">注销</a></h3>
<%}else{ %>
<h3>请先进行系统的<a href=="login.jsp">登录</a>！</h3>
<%} %>
</body>
</html>
3.注销成功页面：
<%@ 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">
<title>Insert title here</title>
</head>
<body>
<%
response.setHeader("refresh","2;URL=login.jsp");
session.invalidate();
%>
<h3>您已成功注销，两秒后跳转回首面</h3>
</body>
</html>
结果：
