每当我重新加载/刷新我的页面，它加倍mysql查询?(PHP) - Whenever I reload/refresh my page, it doubles the mysql query? [PHP]

我正在与我们的项目工作，我注意到每当我刷新我的页面mysql查询重复自己。当我点击一个提交按钮，它会去同一个页面，它会执行查询。尽管我对提交按钮使用了isset()方法，但当我刷新/重新加载页面时，查询仍然会重复。谢谢!

<html>
<body>
<head>
<link rel="stylesheet" type="text/css" href="Homepagestyle.css">
</head>
<form method = "POST" action = "Forum.php">
<?php
session_start();
    mysql_connect("127.0.0.1", "root", "toor");
    mysql_select_db("matutorials");

    echo "Welcome " . "<a href = 'UserProf.php'>". $_SESSION['username'] . "</a> <br>";

    if (isset($_POST['btnProg'])){
        echo $_SESSION['prog'] . "<br>";
    } else if (isset($_POST['btnNet'])){
        echo $_SESSION['net'] . "<br>";
    }
?>
<center><font face = 'verdana'><textarea cols = 70 rows = 6 name = 'txtpost'></textarea></font></center><br>
<center><input type = 'submit' name = 'btnPost'></center><br> <br>
<center><table>

<?php

            if (isset($_POST['btnProg'])){
                $_SESSION['pasamoto'] = 1;
                $capRows = "SELECT * FROM page_post WHERE category_id = 1 ORDER BY timestamps DESC";
                $iQuer = mysql_query($capRows);
                while ($getRows = mysql_fetch_array($iQuer)){
                echo "<tr>";
                echo "<td><div id = 'postsdiv'>" . $getRows['post'] . "</div><br>";
                echo "</tr>";
                }
            }

?> 

</table> </center>
<?php
session_start();
    if(isset($_POST['btnPost'])){
    $post_content = $_POST['txtpost'];
    $dttime = date("Y-m-d") . " " . date("h:i:sa");
    $var = $_SESSION['pasamoto'];

        if ($var == 1){
            $addpost = "INSERT INTO page_post(post,timestamps,category_id) VALUES ('$post_content','$dttime','$var')";
            mysql_query($addpost);
            $capRows = "SELECT * FROM page_post WHERE category_id = '".$var."' ORDER BY timestamps DESC";
            $iQuer = mysql_query($capRows);

                while ($getRows = mysql_fetch_array($iQuer)){
                echo "<tr>";
                echo "<td><div id = 'postsdiv'>" . $getRows['post'] . "</div><br>";
                echo "</tr>";
                }
        }       
        //}
        if ($var == 2){
            $addpost = "INSERT INTO page_post(post,timestamps,category_id) VALUES ('$post_content','$dttime','$var')";
            mysql_query($addpost);
            $capRows = "SELECT * FROM page_post WHERE category_id = '".$var."' ORDER BY timestamps DESC";
            $iQuer = mysql_query($capRows);

                while ($getRows = mysql_fetch_array($iQuer)){
                echo "<tr>";
                echo "<td><div id = 'postsdiv'>" . $getRows['post'] . "</div><br>";
                echo "</tr>";
                }
        }



    //}

?>
</form>
</body>
</html>

如果您在提交表单后刷新页面，POST仍然会被某些浏览器识别，并将导致对代码的第二次POST。您应该更新代码以在单独的页面或函数上触发SQL查询，然后将用户重定向到成功/感谢页面，在这里刷新不会重复查询。

或者，您可以在页面上有一个包含唯一令牌的隐藏字段，并将其与cookie进行比较。在页面加载时，将令牌保存到cookie和表单上的隐藏字段中。提交表单时，验证隐藏表单字段中的令牌是否与cookie匹配，然后删除cookie。在提交后刷新页面将导致令牌验证失败，从而防止重复的SQL插入。

通过在插入查询后重定向页面来清除表单数据像标题(地点:home)

正如@PeeHaa在上面的评论中建议使用Post-Redirect-Get概念。
稍微修改了一下代码。试试下面:

Forum.php

<head>
<link rel="stylesheet" type="text/css" href="Homepagestyle.css">
</head>
<body>
<form method="POST" action="Forum.php">
<?php
    session_start();
    mysql_connect("127.0.0.1", "root", "toor");
    mysql_select_db("matutorials");
    echo "Welcome " . "<a href = 'UserProf.php'>". $_SESSION['username'] . "</a> <br>";
    if (isset($_GET['show']))
    {
        echo $_SESSION['prog'] . "<br>";
    } 
    else if (isset($_GET['show']))
    {
        echo $_SESSION['net'] . "<br>";
    }
?>
<center><font face = 'verdana'><textarea cols = 70 rows = 6 name = 'txtpost'></textarea></font></center><br>
<center><input type = 'submit' name = 'btnPost'></center><br> <br>
<center><table>
<?php
    if (isset($_GET['show'])) 
    {
        $_SESSION['pasamoto'] = 1;
        $capRows = "SELECT * FROM page_post WHERE category_id = 1 ORDER BY timestamps DESC";
        $iQuer = mysql_query($capRows);
        while ($getRows = mysql_fetch_array($iQuer))
        {
            echo "<tr>";
            echo "<td><div id = 'postsdiv'>" . $getRows['post'] . "</div><br>";
            echo "</tr>"; 
        }
     }
?> 
</table> </center>
<?php
    if(isset($_POST['btnPost']))
    {
        $post_content = $_POST['txtpost'];
        $dttime = date("Y-m-d") . " " . date("h:i:sa");
        $var = $_SESSION['pasamoto'];
        if ($var == 1)
        {
           $addpost = "INSERT INTO page_post(post,timestamps,category_id) VALUES ('$post_content','$dttime','$var')";
            mysql_query($addpost);
            $capRows = "SELECT * FROM page_post WHERE category_id = '".$var."' ORDER BY timestamps DESC";
            $iQuer = mysql_query($capRows);

            while ($getRows = mysql_fetch_array($iQuer))
            {
                echo "<tr>";
                echo "<td><div id = 'postsdiv'>" . $getRows['post'] . "</div><br>";
                echo "</tr>";
            }
         }       
        if ($var == 2)
        {
            $addpost = "INSERT INTO page_post(post,timestamps,category_id) VALUES ('$post_content','$dttime','$var')";
            mysql_query($addpost);
            $capRows = "SELECT * FROM page_post WHERE category_id = '".$var."' ORDER BY timestamps DESC";
            $iQuer = mysql_query($capRows);

            while ($getRows = mysql_fetch_array($iQuer))
            {
                echo "<tr>";
                echo "<td><div id = 'postsdiv'>" . $getRows['post'] . "</div><br>";
                echo "</tr>";
            }
        }
    }
    header("Location:Forum.php?show=true");  // <==== Note this
?>
</form>
</body>
</html>

解释:

以上代码将遵循Post-Redirect-Get模式。表单会将数据发送到同一页面表单发送后要执行的任何任务都应该包含在

中

if(isset($_POST['btnPost']))
{
    ...
}

，然后使用

将用户重定向到同一页面

header("Location:Forum.php?show=true");

header函数将用户重定向到同一页面，GET参数show将决定重定向后显示的内容。重定向(或任何其他时间)后显示的内容应包含在

中。

if(isset($_GET['show']))
{
    ...
}