标签：jsp
一：session获取用户的ID
<%@ page language="java"import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c"uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTDHTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘Demo1.jsp‘ starting page</title>
</head>
<body>
<h1>获取用户的ID</h1>
<%
String id=session.getId();
%>
<h3>id:<%=id %></h3>
<h3>id的长度:<%=id.length() %></h3>
</body>
</html>
二：session编写的用户登录程序
Login.jsp
<%@ page language="java"import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c"uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTDHTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘Login.jsp‘ starting page</title>
</head>
<body>
<form action="Login.jsp" method="post">
用户名：<input type="text" name="uname"><br>
密 码：<input type="password"name="pname"><br>
<input type="submit"value="登录">
<input type="reset" value="重置">
</form>
<%
Stringname=request.getParameter("uname");
Stringpassword=request.getParameter("pname");
if(!(name==null||"".equals(password))){
if("Spring".equals(name)&&"123".equals(password)){
response.setHeader("refresh","2;URL=welcome.jsp");
session.setAttribute("userid",name);
%>
<h3>登录成功，两秒跳到欢迎页</h3>
<h3>如果没有跳转，请点击<a href="welcome.jsp">这里</a></h3>
<%
}else{
%>
<h3>程序发生了错误</h3>
<%
}
}
%>
</body>
</html>
welcome.jsp
<%@ page language="java"import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c"uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTDHTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘welcome.jsp‘ starting page</title>
</head>
<body>
<%
if(session.getAttribute("userid")!=null){
%>
<h3>欢迎进入本页：<%=session.getAttribute("userid")%></h3>
<%
}else{
%>
<h3>登录错误，<a href="Login.jsp">重新登录</a></h3>
<%
}
%>
</body>
</html>
loginout.jsp
<%@ page language="java"import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c"uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTDHTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘loginout.jsp‘ starting page</title>
</head>
<body>
<%
response.setHeader("refresh","2;url=Login.jsp");
session.invalidate();//注销
%>
<h3>成功退出本系统</h3>
<h3><a href="Login.jsp">没有跳转点击这里</a></h3>
</body>
</html>
三：判断新老用户
<%@ page language="java"import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c"uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTDHTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘is_New.jsp‘ starting page</title>
</head>
<body>
<%
if(session.isNew()){
%>
<!-- 用户第一次登录 -->
<h3>欢迎光临</h3>
<%
}else{
%>
<h3>欢迎回来</h3>
<%
}
%>
</body>
</html>
四：获取用户在线时间
<%@ page language="java"import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib prefix="c"uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTDHTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP ‘getTime.jsp‘ starting page</title>
</head>
<body>
<%
//获取创建时间
long start=session.getCreationTime();
//获取最后操作时间
long end=session.getLastAccessedTime();
long time=(end-start)/1000;
%>
<h3>在线时间：<%=time %></h3>
</body>
</html>
版权声明：博主原创文章，转载请说明出处。http://blog.csdn.net/dzy21
标签：jsp
原文地址：http://blog.csdn.net/dzy21/article/details/47174539
