我正在使用netbens8中的jsp进行注销的代码。我的数据库在mysql中。我正在尝试为注销超链接编写代码。我已经完成了以下代码。但是我的问题是当我单击一次注销链接时，它不返回，但是当我单击两次注销链接时，它返回了上一页或上一页。我在filelist.jsp页面中创建了一个链接单击此处以注销。当我单击此链接时，它将重新编入logout.jsp页面。我想限制用户返回。怎么做？我在代码某处出错了吗？请建议我。在此先感谢：）
这是我的filelist.jsp页面
<%--
Document : filelist
Created on : 22 Oct, 2019, 7:48:04 PM
Author : Z0009289
--%>
<%@page import="java.sql.DriverManager"%>
<%@page import="java.sql.Statement"%>
<%@page import="com.servlet.db.DB"%>
<%@page import="java.sql.ResultSet"%>
<%@page import="java.sql.PreparedStatement"%>
<%@page import="java.sql.Connection"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%
%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<link href="bootstrap.css" rel="stylesheet" type="text/css">
<title>file_list Page</title>
</head>
<body>
<a href="logout.jsp">Click here to logout</a>
</body>
</html>这是我的logout.jsp页面
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%
response.setHeader("Cache-Control","no-cache");
response.setHeader("Cache-Control","no-store");
response.setHeader("Pragma","no-cache");
response.setDateHeader ("Expires", 0);
session = request.getSession();
String userid = "";
if ((session.getAttribute("userid") == null) || (session.getAttribute("userid") == "")) {
response.sendRedirect("login.jsp");
}
else{
userid = session.getAttribute("userid").toString();
}
%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Log out Page</title>
</head>
<body>
<h2>Are you sure to logout???</h2>
<%
response.setHeader("Cache-Control","no-cache");
response.setHeader("Cache-Control","no-store");
response.setHeader("Pragma","no-cache");
response.setDateHeader ("Expires", 0);
%>
<a href="signout.jsp"><button type="submit">Logout</button></a>
</body>
</html>这是我的signout.jsp页面
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%
response.setHeader("Cache-Control","no-cache");
response.setHeader("Cache-Control","no-store");
response.setHeader("Pragma","no-cache");
response.setDateHeader ("Expires", 0);
%>
<%
session = request.getSession();
String uname = "";
if ((session.getAttribute("userid") == null) || (session.getAttribute("userid") == "")) {
response.sendRedirect("login.jsp");
}
else{
uname = session.getAttribute("userid").toString();
}
%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Sign out Page</title>
</head>
<body>
<%
response.setHeader("Cache-Control","no-cache");
response.setHeader("Cache-Control","no-store");
response.setHeader("Pragma","no-cache");
response.setDateHeader ("Expires", 0);
if(session.getAttribute("userid") != null){
session.removeAttribute("userid");
request.getSession(false);
session.setAttribute("userid", null);
session.invalidate();
response.sendRedirect("login.jsp");
}
%>
</body>
</html>此代码段将为您服务并解决您的错误
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<head>
<META HTTP-EQUIV="Cache-Control" CONTENT="no-cache">
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Expires" CONTENT="-1">
</head>
----//body tags
<%
session.invalidate();
response.setHeader("Cache-Control","no-store");
response.setHeader("Pragma","no-cache");
response.setDateHeader ("Expires", 0);
%>
<jsp:forward page="index.jsp"></jsp:forward>
<li><a href="logout.jsp">Logout</a></li>