本文实例讲述了PHP实现的文件操作类及文件下载功能。分享给大家供大家参考，具体如下：

文件操作类：

<?php // Copyright 2005, Lee Babin (lee@thecodeshoppe.com) // This code may be used and redistributed without charge // under the terms of the GNU General Public // License version 2.0 or later -- www.gnu.org // Subject to the retention of this copyright // and GPL Notice in all copies or derived works class cfile { //The path to the file we wish to work with. protected $thepath; //Error messages in the form of constants for ease of use. const FOUNDERROR = "Sorry, the file in question does not exist."; const PERMERROR = "Sorry, you do not have the proper permissions on this file"; const OPENERROR = "Sorry, the file in question could not be opened."; const CLOSEERROR = "Sorry, the file could not be closed."; //The constructor function. public function __construct (){ $num_args = func_num_args(); if($num_args > 0){ $args = func_get_args(); $this->thepath = $args[0]; } } //A function to open the file. private function openfile ($readorwrite){ //First, ensure the file exists. try { if (file_exists ($this->thepath)){ //Now, we need to see if we are reading or writing or both. $proceed = false; if ($readorwrite == "r"){ if (is_readable($this->thepath)){ $proceed = true; } } elseif ($readorwrite == "w"){ if (is_writable($this->thepath)){ $proceed = true; } } else { if (is_readable($this->thepath) && is_writable($this->thepath)){ $proceed = true; } } try { if ($proceed){ //We can now attempt to open the file. try { if ($filepointer = fopen ($this->thepath, $readorwrite)){ return $filepointer; } else { throw new exception (self::OPENERROR); return false; } } catch (exception $e) { echo $e->getmessage(); } } else { throw new exception (self::PERMERROR); } } catch (exception $e) { echo $e->getmessage(); } } else { throw new exception (self::FOUNDERROR); } } catch (exception $e) { echo $e->getmessage(); } } //A function to close a file. function closefile () { try { if (!fclose ($this->thepath)){ throw new exception (self::CLOSEERROR); } } catch (exception $e) { echo $e->getmessage(); } } //A function to read a file, then return the results of the read in a string. public function read () { //First, attempt to open the file. $filepointer = $this->openfile ("r"); //Now, return a string with the read data. if ($filepointer != false){ //Then we can read the file. return fgets ($filepointer); } //Lastly, close the file. $this->closefile (); } //A function to write to a file. public function write ($towrite) { //First, attempt to open the file. $filepointer = $this->openfile ("w"); //Now, return a string with the read data. if ($filepointer != false){ //Then we can read the file. return fwrite ($filepointer, $towrite); } //Lastly, close the file. $this->closefile (); } //A function to append to a file. public function append ($toappend) { //First, attempt to open the file. $filepointer = $this->openfile ("a"); //Now, return a string with the read data. if ($filepointer != false){ //Then we can read the file. return fwrite ($filepointer, $toappend); } //Lastly, close the file. $this->closefile (); } //A function to set the path to a new file. public function setpath ($newpath) { $this->thepath = $newpath; } }?><?php $myfile = new cfile ("test.txt"); //Now, let's try reading it. echo $myfile->read(); //Then let's try writing to the file. $myfile->write ("Hello World!"); //Then, let's try appending. $myfile->append ("Hello Again!");?>

文件下载：

<?php$filename = 'file1.txt';$file = fopen($filename, 'r');Header("Expires: 0");Header("Pragma: public");Header("Cache-Control: must-revalidate, post-check=0, pre-check=0");Header("Cache-Control: public");Header("Content-Length: ". filesize($filename));Header("Content-Type: application/octet-stream");Header("Content-Disposition: attachment; filename=".$filename);readfile($filename);?>

更多关于PHP相关内容感兴趣的读者可查看本站专题：《php文件操作总结》、《PHP数组(Array)操作技巧大全》、《PHP基本语法入门教程》、《PHP运算与运算符用法总结》、《php面向对象程序设计入门教程》、《PHP网络编程技巧总结》、《php字符串(string)用法总结》、《php+mysql数据库操作入门教程》及《php常见数据库操作技巧汇总》

希望本文所述对大家PHP程序设计有所帮助。