PHP实现的文件操作类及文件下载功能示例
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
//Copyright2005,LeeBabin(lee@thecodeshoppe.com)
//Thiscodemaybeusedandredistributedwithoutcharge
//underthetermsoftheGNUGeneralPublic
//Licenseversion2.0orlater--www.gnu.org
//Subjecttotheretentionofthiscopyright
//andGPLNoticeinallcopiesorderivedworks
classcfile{
//Thepathtothefilewewishtoworkwith.
protected$thepath;
//Errormessagesintheformofconstantsforeaseofuse.
constFOUNDERROR="Sorry,thefileinquestiondoesnotexist.";
constPERMERROR="Sorry,youdonothavetheproperpermissionsonthisfile";
constOPENERROR="Sorry,thefileinquestioncouldnotbeopened.";
constCLOSEERROR="Sorry,thefilecouldnotbeclosed.";
//Theconstructorfunction.
publicfunction__construct(){
$num_args=func_num_args();
if($num_args>0){
$args=func_get_args();
$this->thepath=$args[0];
}
}
//Afunctiontoopenthefile.
privatefunctionopenfile($readorwrite){
//First,ensurethefileexists.
try{
if(file_exists($this->thepath)){
//Now,weneedtoseeifwearereadingorwritingorboth.
$proceed=false;
if($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){
//Wecannowattempttoopenthefile.
try{
if($filepointer=fopen($this->thepath,$readorwrite)){
return$filepointer;
}else{
thrownewexception(self::OPENERROR);
returnfalse;
}
}catch(exception$e){
echo$e->getmessage();
}
}else{
thrownewexception(self::PERMERROR);
}
}catch(exception$e){
echo$e->getmessage();
}
}else{
thrownewexception(self::FOUNDERROR);
}
}catch(exception$e){
echo$e->getmessage();
}
}
//Afunctiontocloseafile.
functionclosefile(){
try{
if(!fclose($this->thepath)){
thrownewexception(self::CLOSEERROR);
}
}catch(exception$e){
echo$e->getmessage();
}
}
//Afunctiontoreadafile,thenreturntheresultsofthereadinastring.
publicfunctionread(){
//First,attempttoopenthefile.
$filepointer=$this->openfile("r");
//Now,returnastringwiththereaddata.
if($filepointer!=false){
//Thenwecanreadthefile.
returnfgets($filepointer);
}
//Lastly,closethefile.
$this->closefile();
}
//Afunctiontowritetoafile.
publicfunctionwrite($towrite){
//First,attempttoopenthefile.
$filepointer=$this->openfile("w");
//Now,returnastringwiththereaddata.
if($filepointer!=false){
//Thenwecanreadthefile.
returnfwrite($filepointer,$towrite);
}
//Lastly,closethefile.
$this->closefile();
}
//Afunctiontoappendtoafile.
publicfunctionappend($toappend){
//First,attempttoopenthefile.
$filepointer=$this->openfile("a");
//Now,returnastringwiththereaddata.
if($filepointer!=false){
//Thenwecanreadthefile.
returnfwrite($filepointer,$toappend);
}
//Lastly,closethefile.
$this->closefile();
}
//Afunctiontosetthepathtoanewfile.
publicfunctionsetpath($newpath){
$this->thepath=$newpath;
}
}
?>
<?php
$myfile=newcfile("test.txt");
//Now,let'stryreadingit.
echo$myfile->read();
//Thenlet'strywritingtothefile.
$myfile->write("HelloWorld!");
//Then,let'stryappending.
$myfile->append("HelloAgain!");
?>
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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希望本文所述对大家PHP程序设计有所帮助。