关于将php转换为pdf

Question

Fatal error: Uncaught exception 'PDFlibException' with message 'Cannot modify header information - headers already sent by (output started at C:\xampp\htdocs\pdf\index.php:2)' 
in C:\xampp\htdocs\pdf\dompdf\include\pdflib_adapter.cls.php:833 Stack trace: 
#0 C:\xampp\htdocs\pdf\dompdf\include\pdflib_adapter.cls.php(833): header('Cache-Control: ...') 
#1 C:\xampp\htdocs\pdf\dompdf\include\dompdf.cls.php(447): PDFLib_Adapter->stream('sample.pdf', NULL) 
#2 C:\xampp\htdocs\pdf\index.php(21): DOMPDF->stream('sample.pdf') 
#3 {main} thrown in C:\xampp\htdocs\pdf\dompdf\include\pdflib_adapter.cls.php on line 833

有人遇到过这种错误吗？我正在使用DOMPDF。

这是我的代码：

<?php

if(isset($_POST['submit']))
{

  $content = $_POST['content'];

  if (empty($content)) {
    $error = 'please enter some content to create your Pdf';
  }

  else{


    include_once( 'dompdf/dompdf_config.inc.php');

    $dompdf = new DOMPDF();
    $dompdf->load_html($content);
    $dompdf->render();
    $dompdf->stream('sample.pdf');

  }

}

?>

Answer 1

在index.php的第2行发送输出：

output started at C:\xampp\htdocs\pdf\index.php:2

有时它只是一条空行！ 复制粘贴整个index.php，请不要修改。