php文件上传类

<?php
header("Content-Type:text/html; charset=utf-8");
if($_POST['submit']){
    $upfiles = new Upload();
    $upfiles->upload_file();
}
class Upload{
    public $upload_name;                    //上传文件名
    public $upload_tmp_name;                //上传临时文件名
    public $upload_final_name;                //上传文件的最终文件名
    public $upload_target_dir;                //文件被上传到的目标目录
    public $upload_target_path;                //文件被上传到的最终路径
    public $upload_filetype ;                //上传文件类型
    public $allow_uploadedfile_type;        //允许的上传文件类型
    public $upload_file_size;                //上传文件的大小
    public $allow_uploaded_maxsize=10000000;     //允许上传文件的最大值
    //构造函数
    public function __construct()
    {
        $this->upload_name = $_FILES["file"]["name"]; //取得上传文件名
        $this->upload_filetype = $_FILES["file"]["type"];
        $this->upload_tmp_name = $_FILES["file"]["tmp_name"];
        $this->allow_uploadedfile_type = array('jpeg','jpg','png','gif','bmp','doc','zip','rar','txt','wps');
        $this->upload_file_size = $_FILES["file"]["size"];
        $this->upload_target_dir="./upload";
    }
    //文件上传
    public function upload_file()
    {
        $upload_filetype = $this->getFileExt($this->upload_name);
        if(in_array($upload_filetype,$this->allow_uploadedfile_type))
        {
            if($this->upload_file_size < $this->allow_uploaded_maxsize)
            {
                if(!is_dir($this->upload_target_dir))
                {
                    mkdir($this->upload_target_dir);
                    chmod($this->upload_target_dir,0777);
                }
                $this->upload_final_name = date("YmdHis").rand(0,100).'.'.$upload_filetype;
                $this->upload_target_path = $this->upload_target_dir."/".$this->upload_final_name;
                if(!move_uploaded_file($this->upload_tmp_name,$this->upload_target_path))
                    echo "<font color=red>文件上传失败！</font>";
            }
            else
            {
                echo("<font color=red>文件太大,上传失败！</font>");
            }
        }
        else
        {
            echo("不支持此文件类型，请重新选择");
        }
    }
   /**
    *获取文件扩展名
    *@param String $filename 要获取文件名的文件
    */
   public function getFileExt($filename){
           $info = pathinfo($filename);
           return $info["extension"];
   }
    
}
?>
<form enctype="multipart/form-data" method="POST" action="">
　　<input type="file" name="file"><input type="submit" name="submit" value="上传">
</form>