一个完整的php文件上传类实例讲解

<?phpdefine('NO_FILE', '不存在上传文件');define('NOT_ALLOW_EXT', '文件类型不在允许范围内');define('NOT_ALLOW_SIZE', '文件大小不在允许范围内');define('HAS_THE_FILE', '该文件已经存在');define('UPLOAD_FAILED', '上传失败');define('UPLOAD_SUCCESS', '上传成功');class file_uploader{  var $_file;  var $_filesize;  var $_fileext;  var $_filedir;  var $_filename;  var $_filetmpname;    var $allowsize;  var $allowext;    var $neednewname;  var $newname;  var $syslang;    var $report;    function ready($filedir = '', $file, $allowsize = '', $allowext = '', $neednewname = false, $report = 0){    $this->_filedir = is_dir($filedir) ? $filedir : '';    if(empty($file) || !isset($file['size']) || $file['size'] == 0) $this->error(NO_FILE);    $this->_filesize = $file['size'];    $this->_filename = $file['name'];    $this->_filetmpname = $file['tmp_name'];        $this->allowsize = $allowsize;    $this->allowext = $allowext;        $this->neednewname = ($neednewname) ? true : false;    $this->newname = '';        $this->report = $report;  }    function do_upload(){    if(!is_uploaded_file($this->_filetmpname)) $this->error(NO_FILE);    if($this->chk_ext()){      $this->error(NOT_ALLOW_EXT);      return '';    }    if($this->chk_size()){      $this->error(NOT_ALLOW_SIZE);      return '';    }    if($this->neednewname) $this->newname = $this->generate_name().".".$this->get_fileext();    if($this->chk_hasfile()){      $this->error(HAS_THE_FILE);      return '';    }    $filename = empty($this->newname) ? @iconv('utf-8','gb2312',$this->_filename) : $this->newname;    @chmod($this->_filedir.$filename, 0777);    if(move_uploaded_file($this->_filetmpname, $this->_filedir.$filename)){      return $this->result();    }else{      $this->error(UPLOAD_FAILED);      return '';    }  }    function chk_ext(){    if(empty($this->allowext) || in_array($this->get_fileext(), explode("|",$this->allowext))) return false;    return true;  }    function chk_size(){    if(empty($this->allowsize) || get_filesize <= $this->allowsize*1024*1024) return false;    return true;  }    function get_filesize(){    return $this->_filesize;  }    function get_fileext(){    return substr($this->_filename,strrpos($this->_filename,".")+1);  }    function generate_name(){    return substr(md5(time()),26);  }    function chk_hasfile(){    return is_file($this->_filedir.$this->_filename);  }    function error($tip){    echo $tip;  }    function result(){    if($this->report){      $filename = empty($this->newname) ? $this->_filename : $this->newname;      $arr = array('filename' => $filename, 'filesize' => $this->_filesize, 'tip' => UPLOAD_SUCCESS);      return $arr;    }else{      return UPLOAD_SUCCESS;    }  }}/***使用方法与参数说明***//***  第一个参数$dir 为上传文件存放的路径   第二个参数为$_FILES 为你那个上传文件变量   第三个参数允许文件大小 单位为MB  第四个参数允许的文件类型 格式为jpg|png|gif  第五个参数是否需要生成新的文件名   第六个参数为返回的提示格式 0为直接提示上传正确 1则返回一个数组array('filename' => $filename, 'filesize' => $this->_filesize, 'tip' => UPLOAD_SUCCESS);***///require("类文件");//$u = new file_uploader;//$u->ready($dir, $_FILES['upload_file'], false, false, true, 0);//echo $u->do_upload();?>

$dir = 'upload/';  require("upload_class.php");  $u = new file_uploader;  $u->ready($dir, $_FILES['upload_file'], false, false, true, 0);  echo $u->do_upload();