PHP image upload class and calling method

<?php
header("Content-Type:text/html; charset=utf-8"); 
//类的实例化：
include("uppoo.php");//类的文件名是upoop.php
$up=newupphoto;
$submit=$_POST[&#39;submit&#39;];
if($submit=="上传"){
$up->get_ph_tmpname($_FILES[&#39;photo&#39;][&#39;tmp_name&#39;]);
$up->get_ph_type($_FILES[&#39;photo&#39;][&#39;type&#39;]);
$up->get_ph_size($_FILES[&#39;photo&#39;][&#39;size&#39;]);
$up->get_ph_name($_FILES[&#39;photo&#39;][&#39;name&#39;]);
$up->save();
}
?>
//上传图片的HTML：
<form action="upphoto.php?action=act" method="post" enctype="multipart/form-data">
图片来源：<input type="file" name="photo">
<input type="submit" name="submit" value="上传">

<?php
class upphoto{
public $previewsize=0.125 ;  //预览图片比例
public $preview=0;  //是否生成预览，是为1，否为0
  public $datetime;  //随机数
  public $ph_name;  //上传图片文件名
  public $ph_tmp_name;  //图片临时文件名
  public $ph_path="./userimg/";  //上传文件存放路径
public $ph_type;  //图片类型
  public $ph_size;  //图片大小
  public $imgsize;  //上传图片尺寸，用于判断显示比例
  public $al_ph_type=array(&#39;image/jpg&#39;,&#39;image/jpeg&#39;,&#39;image/png&#39;,&#39;image/pjpeg&#39;,&#39;image/gif&#39;,&#39;image/bmp&#39;,&#39;image/x-png&#39;);  //允许上传图片类型
  public $al_ph_size=1000000;  //允许上传文件大小
 function __construct(){
  $this->set_datatime();
 }
 function set_datatime(){
  $this->datetime=date("YmdHis");
 }
  //获取文件类型
 function get_ph_type($phtype){
   $this->ph_type=$phtype;
 }
 //获取文件大小
 function get_ph_size($phsize){
   $this->ph_size=$phsize."<br>";
 }
 //获取上传临时文件名
 function get_ph_tmpname($tmp_name){
  $this->ph_tmp_name=$tmp_name;
  $this->imgsize=getimagesize($tmp_name);
 }
 //获取原文件名
 function get_ph_name($phname){
  $this->ph_name=$this->ph_path.$this->datetime.strrchr($phname,"."); //strrchr获取文件的点最后一次出现的位置
//$this->ph_name=$this->datetime.strrchr($phname,"."); //strrchr获取文件的点最后一次出现的位置
return $this->ph_name;
 }
// 判断上传文件存放目录
 function check_path(){
  if(!file_exists($this->ph_path)){
   mkdir($this->ph_path);
  }
 }
 //判断上传文件是否超过允许大小
 function check_size(){
  if($this->ph_size>$this->al_ph_size){
   $this->showerror("上传图片超过2000KB");
  }
 }
 //判断文件类型
 function check_type(){
  if(!in_array($this->ph_type,$this->al_ph_type)){
     $this->showerror("上传图片类型错误");
  }
 }
 //上传图片
  function up_photo(){
  if(!move_uploaded_file($this->ph_tmp_name,$this->ph_name)){
  $this->showerror("上传文件出错");
  }
 }
 //图片预览
  function showphoto(){
   if($this->preview==1){
   if($this->imgsize[0]>2000){
    $this->imgsize[0]=$this->imgsize[0]*$this->previewsize;
       $this->imgsize[1]=$this->imgsize[1]*$this->previewsize;
   }
     echo("<img src=\"{$this->ph_name}\" width=\"{$this->imgsize[&#39;0&#39;]}\" height=\"{$this->imgsize[&#39;1&#39;]}\">");
   }
  }
 //错误提示
 function showerror($errorstr){
  echo "<script language=java script>alert(&#39;$errorstr&#39;);location=&#39;java script:history.go(-1);&#39;;</script>";
  exit();
 }
 function save(){
  $this->check_path();
  $this->check_size();
  $this->check_type();
  $this->up_photo();
  $this->showphoto();
 }
}
?>