php fopen()函数

定义

fopen()函数打开一个文件或URL。

fopen()从C直接提起。

语法

PHP fopen()函数具有以下语法。

fopen(filename,mode,include_path,context)

参数

mode的可能值：

返回值

成功时返回文件指针资源，如果出错则返回FALSE。

我们可以通过在函数名前添加一个“@”来隐藏错误输出。

实例1

看看下面的用法：

$file1 = fopen(\"file.txt\", \"r\") OR die (\"Can\'t open file!\\n\");
$file2= fopen(\"$logFileName\", \"w\") OR die (\"Log file not writeable!\\n\");

fopen()函数返回文件句柄资源。您应该将fopen()的返回值存储在变量中，以供以后使用：

<?php
/*
http://www.manongjc.com/article/1795.html
作者：码农教程
*/
      $filename = \"c:/abc/test.txt\";
      $handle = fopen($filename, \"a\");
      if (!$handle) {
             print \"Failed to open $filename for appending.\\n\";
      }
?>

示例 - 打开远程文件

fopen()可以打开远程文件。PHP自动为您打开HTTP/FTP连接，返回文件句柄。

此示例通过您的浏览器显示码农教程网站：

<?php
/*
http://www.manongjc.com/article/1795.html
作者：码农教程
*/
$google = fopen(\"http://www.manongjc.com\", \"r\");
$site = fread($google, 200000);
fclose($google);
print $site;
?>

指定r模式是因为Web服务器不允许通过HTTP进行写入，

$file = fopen(\"http://www.example.com/\",\"r\");
$file = fopen(\"ftp://user:password@example.com/test.txt\",\"w\");

实例2

以下代码显示如何打开文件或URL。

<?php
    $file = fopen(\"test.txt\",\"r\");
    $file = fopen(\"test.txt\",\"r\");
    $file = fopen(\"test.txt\",\"wb\");
    $file = fopen(\"http://www.example.com/\",\"r\");
    $file = fopen(\"ftp://user:password@example.com/test.txt\",\"w\");
/*
http://www.manongjc.com/article/1795.html
作者：码农教程
*/

/*
      \"r\" (Read only. Starts at the beginning of the file)
      \"r+\" (Read/Write. Starts at the beginning of the file)
      \"w\" (Write only. Opens and clears the contents of file; or creates a new file if it doesn\'t exist)
      \"w+\" (Read/Write. Opens and clears the contents of file; or creates a new file if it doesn\'t exist)
      \"a\" (Write only. Opens and writes to the end of the file or creates a new file if it doesn\'t exist)
      \"a+\" (Read/Write. Preserves file content by writing to the end of the file)
      \"x\" (Write only. Creates a new file. Returns FALSE and an error if file already exists)
      \"x+\" (Read/Write. Creates a new file. Returns FALSE and an error if file already exists)

*/
?>

实例3

以下代码显示了如何打开现有文件“test.txt”，并向其中写入一些新数据。

<?php
/*
http://www.manongjc.com/article/1795.html
作者：码农教程
*/
   $myfile = fopen(\"test.txt\", \"w\") or die(\"Unable to open file!\");
   $txt = \"data\\n\";
   fwrite($myfile, $txt);
   $txt = \"data\\n\";
   fwrite($myfile, $txt);
   fclose($myfile);
?>