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：
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<?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);
?>
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