顯示先前會話資料的JSP頁面-有解無憂

我在jsp中創建了一個登錄表單。還制作了會話保存系統，當用戶登錄時，他的用戶名將在標簽標簽內的歡迎頁面中可見。我為此使用了此代碼-

在登錄頁面：

request.getSession().setAttribute("username",username);

在歡迎頁面中：

out.print(request.getSession().getAttribute("username"));

還有一個像錨標簽這樣的注銷鏈接 href="/login.jsp"

現在我來解決這個問題。當我第一次使用用戶名“a”登錄時，它成功地在歡迎頁面中顯示“a”。但是當我注銷并使用用戶名“b”再次登錄時，它也會在歡迎頁面中顯示“a”。當我重繪瀏覽器時，它會顯示“b”。我可以嘗試一種方法，我可以制作一個在第一次重繪后重繪瀏覽器的代碼。但是我的頁面將來會太重。為此，這不是標準方式，對嗎？

我找到了一個解決方案，session.invalidate();但我在錨標記中嘗試了這段代碼，但沒有用。

請幫助！

這是注銷頁面代碼 -

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <link rel="stylesheet" type="text/css" href="css/style.css">
    <script type="text/javascript" src="js/basic.js"></script>
    <title>Dashboard || XCEL-ERP</title>
</head>
<body>
    <div class="dashboard_sidebar" id="dashboard_sidebar">
        <ul>
            <li class="sidebar_item"><a href="#">HOME</a></li>
            <li class="sidebar_item"><a href="#">RECIPE & COSTING</a></li>
            <li class="sidebar_item"><a href="#">PLANNING</a></li>
            <li class="sidebar_item"><a href="#">PRODUCTION</a></li>
            <li class="sidebar_item"><a href="#">ACCOUNT</a></li>
            <li class="sidebar_item"><a href="#">OVERVIEW</a></li>
        </ul>
    </div>
    <div class="dashboard_header" id="dashboard_header">
        <div class="dashboard_hamburger" onclick="sidebarFunction()">
            <span></span>
            <span></span>
            <span></span>
        </div>
        <div class="logo">ERP</div>
        <div class="user">
            <img src="https://www.dropbox.com/s/s3wcx1zot0gp3fe/user_icon.png?raw=1" alt="user" onclick="userProfileFunction()">
            <label>
             <%  

                out.print(request.getSession().getAttribute("username"));

             %>
             </label>
             <div class="userProfileBox" id="userProfileBox">
                <img src="https://www.dropbox.com/s/zq3d2dz63y3y4ct/man_pic.jpg?raw=1" alt="Profile_img">
                <div class="userName"> <% out.print(request.getSession().getAttribute("username")); %> </div>
                <div class="desg_Section"> Costing Officer - Wash </div>
                <div class="authorization">User has authorization of : </div>
                <button>Log Out</button>
             </div>
        </div>
        <a href="login.jsp">Log Out</a>
    </div>
</body>
</html>

這是連接到表單方法帖子的登錄連接代碼 -

<%@ page import = "java.sql.*"%>
<%

    String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    String DB_URL = "jdbc:mysql://localhost:3306/erp";
    String DB_USER = "root";
    String DB_PASS = "";

    Connection conn = null;
    Statement stm = null;
    ResultSet rs = null;

    String username = request.getParameter("username");
    String password = request.getParameter("password");

    String query = "SELECT * FROM userdata WHERE UserName = '".concat(username).concat("' AND Password = '").concat(password).concat("'");

    try{
        Class.forName(JDBC_DRIVER);
        conn = DriverManager.getConnection(DB_URL, DB_USER, DB_PASS);
        stm = conn.createStatement();

        rs = stm.executeQuery(query);

        Boolean match_result = rs.isBeforeFirst();

        if(match_result == true){

            getServletContext().getRequestDispatcher("/dashboard.jsp").forward(request, response);

            
            request.getSession().setAttribute("username",username);

        }else{

            out.print("Sorry, username or password error!");  
            request.getRequestDispatcher("/login.jsp").forward(request, response);
            
        }

        rs.close();
        stm.close();
        conn.close();
    } catch(Exception e){
        out.println(e);
    }

%>

uj5u.com熱心網友回復：

問題是首先你request去/dashboard.jsp頁面然后你session同時創建，你的標簽顯示以前創建的會話，因為你的頁面首先加載然后通過會話......

必須加載頁面以在 Java 或任何其他編程中獲取新會話

使用request.getRequestDispatcher()代替getServletContext().getRequestDispatcher。rs.isBeforeFirst()不適用于 RowCount 使用，isBeforeFirst()如果找到資料則選擇第一行...

這是修改后的代碼：

登錄.jsp

<%@ page import = "java.sql.*"%>
<%

    String JDBC_DRIVER = "com.mysql.jdbc.Driver";
    String DB_URL = "jdbc:mysql://localhost:3306/erp";
    String DB_USER = "root";
    String DB_PASS = "";

    Connection conn = null;
    ResultSet rs = null;

    if (request.getParameter("btnLogin") != null) {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        try {
            Class.forName(JDBC_DRIVER);
            conn = DriverManager.getConnection(DB_URL, DB_USER, DB_PASS);
            String query = "SELECT * FROM userdata WHERE UserName = '".concat(username).concat("' AND Password = '").concat(password).concat("'");
            PreparedStatement pst = conn.prepareStatement(query);
            rs = pst.executeQuery();
            if (rs.next()) {
                request.getSession().setAttribute("username", username);
                request.getRequestDispatcher("/dashboard.jsp").forward(request, response);
            } else {
                out.print("Sorry, username or password error!");
                request.getRequestDispatcher("/login.jsp").forward(request, response);

            }

            pst.close();
            conn.close();
        } catch (Exception e) {
            out.println(e);
        }
    }

%>

<form method="post">
    <input type="text" name="username">
    <input type="password" name="password">
    <input type="submit" name="btnLogin" value="submit">
</form>

儀表板.jsp

<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8">
    <link rel="stylesheet" type="text/css" href="css/style.css">
    <script type="text/javascript" src="js/basic.js"></script>
    <title>Dashboard || XCEL-ERP</title>
</head>
<body>
    <div class="dashboard_sidebar" id="dashboard_sidebar">
        <ul>
            <li class="sidebar_item"><a href="#">HOME</a></li>
            <li class="sidebar_item"><a href="#">RECIPE & COSTING</a></li>
            <li class="sidebar_item"><a href="#">PLANNING</a></li>
            <li class="sidebar_item"><a href="#">PRODUCTION</a></li>
            <li class="sidebar_item"><a href="#">ACCOUNT</a></li>
            <li class="sidebar_item"><a href="#">OVERVIEW</a></li>
        </ul>
    </div>
    <div class="dashboard_header" id="dashboard_header">
        <div class="dashboard_hamburger" onclick="sidebarFunction()">
            <span></span>
            <span></span>
            <span></span>
        </div>
        <div class="logo">ERP</div>
        <div class="user">
            <img src="https://www.dropbox.com/s/s3wcx1zot0gp3fe/user_icon.png?raw=1" alt="user" onclick="userProfileFunction()">
            <label>
             <%  

                out.print(request.getSession().getAttribute("username"));

             %>
             </label>
             <div class="userProfileBox" id="userProfileBox">
                <img src="https://www.dropbox.com/s/zq3d2dz63y3y4ct/man_pic.jpg?raw=1" alt="Profile_img">
                <div class="userName"> <% out.print(request.getSession().getAttribute("username")); %> </div>
                <div class="desg_Section"> Costing Officer - Wash </div>
                <div class="authorization">User has authorization of : </div>
             </div>
        </div>
        <a href="RemoveSession.jsp">Log Out</a>
    </div>
</body>
</html>

洗掉會話.jsp

<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>JSP Page</title>
    </head>
    <body>
        <form method="post">
            <%
                session.invalidate();
                request.getRequestDispatcher("/login.jsp").forward(request, response);
                
            %>
        </form>
    </body>
</html>

轉載請註明出處，本文鏈接：https://www.uj5u.com/yidong/312461.html

標籤：爪哇谷歌浏览器 jsp 会议

上一篇：洗掉URL引數后保持PHP會話處于活動狀態

下一篇：使用Laravel在會話中獲取緯度和經度并設定默認值？