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：

 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;
  }
 }
?>

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：

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希望本文所述对大家PHP程序设计有所帮助。