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疑难解答“警告：会话_start（）：无法发送会话缓存限制器-已发送头”


我得到警告：session_start（）[function.session-start]：无法发送会话缓存限制器-报头已经发送（输出开始时出错

如果我提交表单数据到一个不同的文件进行处理，它的工作。但是，如果我提交表单数据到同一页，它会给出这个错误。

请告诉我

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<link href="style.css" rel="stylesheet" type="text/css" />
<title>Welcome</title>


<script type="text/javascript" src="jquery.js"></script>
    <script type="text/javascript">
$(document).ready(function () { 

    $('#nav li').hover(
        function () {
            //show its submenu
            $('ul', this).slideDown(100);

        }, 
        function () {
            //hide its submenu
            $('ul', this).slideUp(100);         
        }
    );

});
    </script>

</head>

<body>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
  <tr>
    <td class="header">&nbsp;</td>
  </tr>
  <tr>
    <td class="menu"><table align="center" cellpadding="0" cellspacing="0" width="80%">
    <tr>
    <td>

    <ul id="nav">
    <li><a href="#">Catalog</a>
    <ul><li><a href="#">Products</a></li>
        <li><a href="#">Bulk Upload</a></li>
        </ul>
        <div class="clear"></div>
        </li>


    <li><a href="#">Purchase  </a>

    </li>
    <li><a href="#">Customer Service</a>
    <ul>
        <li><a href="#">Contact Us</a></li>
        <li><a href="#">CS Panel</a></li>

    </ul>           
        <div class="clear"></div>
    </li>
    <li><a href="#">All Reports</a></li>
    <li><a href="#">Configuration</a>
    <ul> <li><a href="#">Look and Feel </a></li>
         <li><a href="#">Business Details</a></li>
         <li><a href="#">CS Details</a></li>
         <li><a href="#">Emaqil Template</a></li>
         <li><a href="#">Domain and Analytics</a></li>
         <li><a href="#">Courier</a></li>
         </ul>
    <div class="clear"></div>
    </li>
    <li><a href="#">Accounts</a>
    <ul><li><a href="#">Ledgers</a></li>
        <li><a href="#">Account Details</a></li>
        </ul>
         <div class="clear"></div></li>

</ul></td></tr></table></td>
  </tr>
  <tr>
    <td valign="top"><table width="80%" border="0" align="center" cellpadding="0" cellspacing="0">
      <tr>
        <td valign="top"><table width="100%" border="0" cellspacing="0" cellpadding="2">
          <tr>
            <td width="22%" height="327" valign="top"><table width="100%" border="0" cellspacing="0" cellpadding="2">
              <tr>
                <td>&nbsp;</td>
                </tr>
              <tr>
                <td height="45"><strong>-&gt; Products</strong></td>
                </tr>
              <tr>
                <td height="61"><strong>-&gt; Categories</strong></td>
                </tr>
              <tr>
                <td height="48"><strong>-&gt; Sub Categories</strong></td>
                </tr>
            </table></td>
            <td width="78%" valign="top"><table width="100%" border="0" cellpadding="0" cellspacing="0">
              <tr>
                <td>&nbsp;</td>
                </tr>
              <tr>
                <td>
                  <table width="90%" border="0" cellspacing="0" cellpadding="0">
                    <tr>
                      <td width="26%">&nbsp;</td>
                      <td width="74%"><h2>Manage Categories</h2></td>
                    </tr>
                  </table></td>
                </tr>
              <tr>
                <td height="30">&nbsp;

                </td>
                </tr>
              <tr>
                <td>


</td>
                </tr>

                <tr>
                <td>
                <table width="49%" align="center" cellpadding="0" cellspacing="0">
                <tr><td>




<?php


                if (isset($_SESSION['error']))

                {

                    echo "<span id=\"error\"><p>" . $_SESSION['error'] . "</p></span>";

                    unset($_SESSION['error']);

                }

                ?>

                <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" enctype="multipart/form-data">

                <p>
                 <label class="style4">Category Name</label>

                   &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <input type="text" name="categoryname" /><br /><br />

                    <label class="style4">Category Image</label>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

                    <input type="file" name="image" /><br />

                    <input type="hidden" name="MAX_FILE_SIZE" value="100000" />

                   <br />
<br />
 <input type="submit" id="submit" value="UPLOAD" />

                </p>

                </form>




                             <?php

session_start();

require("includes/conn.php");


function is_valid_type($file)

{

    $valid_types = array("image/jpg", "image/jpeg", "image/bmp", "image/gif", "image/png");



    if (in_array($file['type'], $valid_types))

        return 1;

    return 0;
}

function showContents($array)

{

    echo "<pre>";

    print_r($array);

    echo "</pre>";
}


$TARGET_PATH = "images/category";

$cname = $_POST['categoryname'];

$image = $_FILES['image'];

$cname = mysql_real_escape_string($cname);

$image['name'] = mysql_real_escape_string($image['name']);

$TARGET_PATH .= $image['name'];

if ( $cname == "" || $image['name'] == "" )

{

    $_SESSION['error'] = "All fields are required";

    header("Location: managecategories.php");

    exit;

}

if (!is_valid_type($image))

{

    $_SESSION['error'] = "You must upload a jpeg, gif, or bmp";

    header("Location: managecategories.php");

    exit;

}




if (file_exists($TARGET_PATH))

{

    $_SESSION['error'] = "A file with that name already exists";

    header("Location: managecategories.php");

    exit;

}


if (move_uploaded_file($image['tmp_name'], $TARGET_PATH))

{



    $sql = "insert into Categories (CategoryName, FileName) values ('$cname', '" . $image['name'] . "')";

    $result = mysql_query($sql) or die ("Could not insert data into DB: " . mysql_error());

  header("Location: mangaecategories.php");

    exit;

}

else

{





    $_SESSION['error'] = "Could not upload file.  Check read/write persmissions on the directory";

    header("Location: mangagecategories.php");

    exit;

}

?>

这是显示代码

<?php  
                  require("includes/conn.php"); 



                $sql = "select CategoryID, CategoryName, FileName, Status from Categories";

                $result = mysql_query($sql) or die ("Could not access DB: " . mysql_error());



                while ($row = mysql_fetch_assoc($result))

                {

                     echo "<table border='0' cellpadding='10'>";


                                        echo "<tr><td>  </td><td>Category ID</td><td>Category Name</td><td>Status</td><td>Edit</td><td>Delete</td></tr>";

                                        echo "<tr><td> <img src=\"images/" . $row['FileName'] . "\" alt=\"\" /> </td>";
                                        echo "<td>". $row['CategoryID'] . "</td>";
                                            echo "<td>". $row['CategoryName'] . "</td>";
                                            echo "<td>". $row['Status']. "</td>";
                                            echo "<td> <a href= 'edit.php?CategoryID=" .$row['id']. "'> Edit </a></td>";
                                            echo "<td> <a href= 'delete.php?CategoryID=" .$row['id']. "'> Edit </a></td>";
                                         echo "</tr> </table>";

                }



            ?>

这里什么也没发生。请建议


共3个答案

匿名用户

您会发现我在页面的最顶端添加了session_start（）。我还删除了页面后面的session_start（）调用。这一页应该很好用。

<?php
session_start();
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<link href="style.css" rel="stylesheet" type="text/css" />
<title>Welcome</title>


<script type="text/javascript" src="jquery.js"></script>
    <script type="text/javascript">
$(document).ready(function () { 

    $('#nav li').hover(
        function () {
            //show its submenu
            $('ul', this).slideDown(100);

        }, 
        function () {
            //hide its submenu
            $('ul', this).slideUp(100);         
        }
    );

});
    </script>

</head>

<body>
<table width="100%" border="0" cellspacing="0" cellpadding="0">
  <tr>
    <td class="header">&nbsp;</td>
  </tr>
  <tr>
    <td class="menu"><table align="center" cellpadding="0" cellspacing="0" width="80%">
    <tr>
    <td>

    <ul id="nav">
    <li><a href="#">Catalog</a>
    <ul><li><a href="#">Products</a></li>
        <li><a href="#">Bulk Upload</a></li>
        </ul>
        <div class="clear"></div>
        </li>


    <li><a href="#">Purchase  </a>

    </li>
    <li><a href="#">Customer Service</a>
    <ul>
        <li><a href="#">Contact Us</a></li>
        <li><a href="#">CS Panel</a></li>

    </ul>           
        <div class="clear"></div>
    </li>
    <li><a href="#">All Reports</a></li>
    <li><a href="#">Configuration</a>
    <ul> <li><a href="#">Look and Feel </a></li>
         <li><a href="#">Business Details</a></li>
         <li><a href="#">CS Details</a></li>
         <li><a href="#">Emaqil Template</a></li>
         <li><a href="#">Domain and Analytics</a></li>
         <li><a href="#">Courier</a></li>
         </ul>
    <div class="clear"></div>
    </li>
    <li><a href="#">Accounts</a>
    <ul><li><a href="#">Ledgers</a></li>
        <li><a href="#">Account Details</a></li>
        </ul>
         <div class="clear"></div></li>

</ul></td></tr></table></td>
  </tr>
  <tr>
    <td valign="top"><table width="80%" border="0" align="center" cellpadding="0" cellspacing="0">
      <tr>
        <td valign="top"><table width="100%" border="0" cellspacing="0" cellpadding="2">
          <tr>
            <td width="22%" height="327" valign="top"><table width="100%" border="0" cellspacing="0" cellpadding="2">
              <tr>
                <td>&nbsp;</td>
                </tr>
              <tr>
                <td height="45"><strong>-&gt; Products</strong></td>
                </tr>
              <tr>
                <td height="61"><strong>-&gt; Categories</strong></td>
                </tr>
              <tr>
                <td height="48"><strong>-&gt; Sub Categories</strong></td>
                </tr>
            </table></td>
            <td width="78%" valign="top"><table width="100%" border="0" cellpadding="0" cellspacing="0">
              <tr>
                <td>&nbsp;</td>
                </tr>
              <tr>
                <td>
                  <table width="90%" border="0" cellspacing="0" cellpadding="0">
                    <tr>
                      <td width="26%">&nbsp;</td>
                      <td width="74%"><h2>Manage Categories</h2></td>
                    </tr>
                  </table></td>
                </tr>
              <tr>
                <td height="30">&nbsp;

                </td>
                </tr>
              <tr>
                <td>


</td>
                </tr>

                <tr>
                <td>
                <table width="49%" align="center" cellpadding="0" cellspacing="0">
                <tr><td>




<?php


                if (isset($_SESSION['error']))

                {

                    echo "<span id=\"error\"><p>" . $_SESSION['error'] . "</p></span>";

                    unset($_SESSION['error']);

                }

                ?>

                <form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" enctype="multipart/form-data">

                <p>
                 <label class="style4">Category Name</label>

                   &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <input type="text" name="categoryname" /><br /><br />

                    <label class="style4">Category Image</label>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

                    <input type="file" name="image" /><br />

                    <input type="hidden" name="MAX_FILE_SIZE" value="100000" />

                   <br />
<br />
 <input type="submit" id="submit" value="UPLOAD" />

                </p>

                </form>




                             <?php


require("includes/conn.php");


function is_valid_type($file)

{

    $valid_types = array("image/jpg", "image/jpeg", "image/bmp", "image/gif", "image/png");



    if (in_array($file['type'], $valid_types))

        return 1;

    return 0;
}

function showContents($array)

{

    echo "<pre>";

    print_r($array);

    echo "</pre>";
}


$TARGET_PATH = "images/category";

$cname = $_POST['categoryname'];

$image = $_FILES['image'];

$cname = mysql_real_escape_string($cname);

$image['name'] = mysql_real_escape_string($image['name']);

$TARGET_PATH .= $image['name'];

if ( $cname == "" || $image['name'] == "" )

{

    $_SESSION['error'] = "All fields are required";

    header("Location: managecategories.php");

    exit;

}

if (!is_valid_type($image))

{

    $_SESSION['error'] = "You must upload a jpeg, gif, or bmp";

    header("Location: managecategories.php");

    exit;

}




if (file_exists($TARGET_PATH))

{

    $_SESSION['error'] = "A file with that name already exists";

    header("Location: managecategories.php");

    exit;

}


if (move_uploaded_file($image['tmp_name'], $TARGET_PATH))

{



    $sql = "insert into Categories (CategoryName, FileName) values ('$cname', '" . $image['name'] . "')";

    $result = mysql_query($sql) or die ("Could not insert data into DB: " . mysql_error());

  header("Location: mangaecategories.php");

    exit;

}

else

{





    $_SESSION['error'] = "Could not upload file.  Check read/write persmissions on the directory";

    header("Location: mangagecategories.php");

    exit;

}

?>

匿名用户

答案就在罗斯的上面。

首先，将session_start（）作为第一行代码将意味着您无法将任何对象正确地反序列化到session变量中。

出现此问题的原因是99%可能是include文件末尾的尾随空格（是的-我知道这听起来不太可能，但请尝试一下）。有问题的文件在错误消息中。我想备份罗斯的答案，这对我来说很有效，但这个网站是反直觉的。

忽略那些胡说八道的回答。删除尾随空格，换行符等...罗斯知道他在说什么。将session_start（）放在文件的顶部确实有效，但这不是正确的解决方案。

匿名用户

我也有同样的问题，但我的解决方案没有建议的那么明显。事实证明，我的php文件是用UTF-8编写的，这导致了一些问题。我将整个文件的内容复制/粘贴到一个新的php文件中（记事本告诉我这是用ANSI而不是UTF-8编写的），现在它可以完美地工作。

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