excel文件上传问题php

Question

我正在尝试上传excel文件，但它失败并显示错误：

“上传不成功”。我正在尝试两个不同的excel文件，但它显示了这个错误。我怎么能解决这个问题？

应该是什么问题？

这是代码：

require_once("connection.php");
if(isset($_POST['submit']))
{
        $target_dir = "misc/";
        $target_file = $target_dir . basename($_FILES["ex_file"]["name"]);
        $uploadOk = 1;
        $FileType = pathinfo($target_file,PATHINFO_EXTENSION);
        //echo $FileType;exit;
        if (file_exists($target_file)) {

                        $_SESSION['message']="Sorry, file already exists. Rename the file , Try Again";
                     echo $_SESSION['message'];exit;
                     $uploadOk = 0;
            }
        // Check file size
        if ($_FILES["ex_file"]["size"] > 5000000) {
                $_SESSION['message']="Sorry, your file is too large.";
               echo  $_SESSION['message'];exit;
                     $uploadOk = 0;
            }
// Allow certain file formats
        if($FileType != "xls" && $FileType != "xlsx" ) {
                    $_SESSION['message']= "Sorry, only xls & xlsx files are allowed.";
                       echo  $_SESSION['message'];exit;
                    $uploadOk = 0;
        }
// Check if $uploadOk is set to 0 by an error
        if ($uploadOk == 0) {
              $_SESSION['message']=  "Sorry, your file was not uploaded.";
        // if everything is ok, try to upload file
        } else {
                     if (move_uploaded_file($_FILES["ex_file"]["tmp_name"], $target_file)) {
                        $_SESSION['message']="Upload Successfull";
               // echo "The file ". basename( $_FILES["fileToUpload"]["name"]). " has been uploaded.";
            } else {
                $_SESSION['message']="Upload Unsuccessfull... Try Again";
                //echo "Sorry, there was an error uploading your file.";
            }
}
            header('location:excel.php');


}

这里是html文件：

<form action="excel_upload.php" method="post" enctype="multipart/form-data" id="MyUploadForm">
                                     <input name="type" value="excel" type="hidden" />

                                     <input name="ex_file" id="ex_file" type="file" />
                                         <input type="submit" name="submit" id="submit-btn" value="Upload" />
                                        <img src="img/ajax-loader.gif" id="loading-img" style="display:none;" alt="Please Wait"/>
                                </form>

提前感谢。

是上传大小限制问题吗？