PHP-文件上传封装类

<?php
$file = $_FILES['img'];

$obj = new File();
$res = $obj->upload($file,'upload');
if($res){
    echo $res;
}else{
    echo File::$error;
}

//sleep(30);

//Array ( [name] => wjdk.png [type] => image/png [tmp_name] => C:\Windows\php955D.tmp [error] => 0 [size] => 668730 )

class File{

    //设置属性：保存允许上传的Mime类型
    private static $types = array('image/jpg','imgae/jpeg','image/pjpeg','image/png');

    //修改允许上传的文件类型
    public static function setType($type=array()){
        if(!empty($type)){
            self::$types = $type;
        }
    }
    public static $error;
    //记录文件上传过程中出现的错误

    //上传方法

    public static function upload($file,$path,$max = 2000000){
        //判断文件有效性
        if(!isset($file['error']) || count($file) != 5){
            self::$error = '错误的上传文件';
            return false;
        }
        if(!is_dir($path)){
            self::$error = '文件路径不存在';
            return false;
        }
        //判定文件是否正确上传
        switch ($file['error']){
            case 1:
            case 2:
                self::$error = '文件超过服务器允许大小';
                return false;
            case 3:
                self::$error = '文件只有部分被上传';
                return false;
            case 4:
                self::$error = '没有选中要上传的文件';
                return false;
            case 6:
                self::$error = '找不到临时文件夹';
                return false;
            case 7:
                self::$error = '文件写入失败';
                return false;
        }
        //判定文件类型
        if(!in_array($file['type'],self::$types)){
            self::$error = '当前上传的文件类型不允许';
            return false;
        }

        //判断文件大小
        if($file['size'] > $max){
            self::$error = '当前上传的文件超过允许的大小,当前允许的大小为'.string()($max/1024/1024).'M';
            return false;
        }

        $filename = self::getRandomName($file['name']);

        if(move_uploaded_file($file['tmp_name'],$path.'/'.$filename)){
            return $filename;
        }else{
            self::$error = '文件移动失败';
            return false;
        }
    }

    public static function getRandomName($filename,$prefix = 'image'){
        $ext = strrchr($filename,'.');
        $new_name = $prefix.date('YmdHis');
        for($i=0;$i<6;$i++){
            $new_name .= chr(mt_rand(65,90));
        }
        return $new_name.$ext;

    }
}