PHP实现图片上传并生成缩略图

接解决上传文件失败后，网上找了一段不错的（比较全面且严谨）PHP后台实现文件处理的代码，并解决原来代码中两个错误后记录如下：
需要修改的字段有$filename,$filemax,$filepath，其余基本不需要再做修改了

<?php

class upload{
    protected $filename;//文件名
    protected $fileMine;//文件上传类型
    protected $filepath;//文件上传路径
    protected $filemax;//文件上传大小
    protected $fileExt;//文件上传格式
    protected $fileerror;//文件出错设置
    protected $fileflag;//文件检测
    protected $fileinfo; //FILES
    protected $ext; //文件扩展
    protected $path;
//文件上传
    public function __construct($filename="N_File",$filemax=5000000,$filepath="Notices",$fileflag=true,$fileExt=array('gif','jpeg','pjpeg','jpg','png'),$fileMine=array('image/gif','image/jpeg','image/pjpeg','image/jpg','image/png'))
    {
        $this->filename=$filename;
        $this->fileinfo=$_FILES[$this->filename];
        $this->filemax=$filemax;
        $this->filepath=$filepath;
        $this->fileflag=$fileflag;
        $this->fileExt=$fileExt;
        $this->fileMine=$fileMine;
//var_dump($this->filename);
    }
//错误判断
    public function UpError(){
        if($this->fileinfo['error']>0){
            switch($this->fileinfo['error'])
            {
                case 1:
                    $this->fileerror="上传文件大小超过服务器允许上传的最大值，php.ini中设置upload_max_filesize选项限制的值 ";
                    break;
                case 2:
                    $this->fileerror="上传文件大小超过HTML表单中隐藏域MAX_FILE_SIZE选项指定的值";
                    break;
                case 3:
                    $this->fileerror="文件部分被上传";
                    break;
                case 4:
                    $this->fileerror="没有选择上传文件";
                    break;
                case 5:
                    $this->fileerror="未找到临时目录";
                    break;
                case 6:
                    $this->fileerror="文件写入失败";
                    break;
                case 7:
                    $this->fileerror="php文件上传扩展没有打开";
                    break;
                case 8:
                    $this->fileerror="";
                    break;
            }
            return false;
        }
        return true;
    }
//检测文件类型
    public function UpMine(){
        if(!in_array($this->fileinfo['type'],$this->fileMine)) {
            $this->error="文件上传类型不对";
            return false;
        }
        return true;
    }
//检测文件格式
    public function UpExt(){
        $this->ext=pathinfo($this->fileinfo['name'],PATHINFO_EXTENSION);
//var_dump($ext);
        if(!in_array($this->ext,$this->fileExt)){
            $this->fileerror="文件格式不对";
            return false;
        }
        return true;
    }
//检测文件路径
    public function UpPath(){
        $mtime=date('Y-m-d');
        $this->filepath=$this->filepath.'/'.$mtime;
        if(!file_exists($this->filepath)){
            mkdir($this->filepath,0777,true);
        }
    }
//检测文件大小
    public function UpSize(){
        $max=$this->fileinfo['size'];
        if($max>$this->filemax){
            $this->fileerror="文件过大";
            return false;
        }
        return true;
    }
//检测文件是否HTTP
    public function UpPost(){
        if(!is_uploaded_file($this->fileinfo['tmp_name'])){
            $this->fileerror="恶意上偿还";
            return false;
        }
        return true;
    }
//文件名防止重复
    public function Upname(){
        return md5(uniqid(microtime(true),true));
    }
//图片缩略图
    public function Smallimg($x=300,$y=300){
        $imgAtt=getimagesize($this->path);
//图像宽，高，类型
        $imgWidth=$imgAtt[0];
        $imgHeight=$imgAtt[1];
        $imgext=$imgAtt[2];
//等比列缩放
        if(($x/$imgWidth)>($y/$imgHeight)){
            $bl=$y/$imgHeight;
        }else{
            $bl=$x/$imgWidth;
        }
        $x=floor($imgWidth*$bl); //缩放后
        $y=floor($imgHeight*$bl);
        $images=imagecreatetruecolor($x,$y);
        switch($imgext){
            case 1:
                $imageout=imagecreatefromgif($this->path);
                break;
            case 2:
                $imageout=imagecreatefromjpeg($this->path);
                break;
            case 3:
                $imageout=imagecreatefrompng($this->path);
                break;
            default:
                $imageout=imagecreatefromjpeg($this->path);
        }
        imagecopyresized($images,$imageout,0,0,0,0,$x,$y,$imgWidth,$imgHeight);
        $names=$this->Upname();
        $this->path=$this->filepath.'/'. $names.'.'.$this->ext;
        imagejpeg($images,$this->path);
        return $this->path;
    }
//文件上传
    public function uploads()
    {
        if($this->UpError()&&$this->UpMine()&&$this->UpExt()&&$this->UpSize()&&$this->UpPost()){
            $this->UpPath();
            $names=$this->Upname();
            $this->path=$this->filepath.'/'. $names.'.'.$this->ext;
            if(move_uploaded_file($this->fileinfo['tmp_name'], $this->path)){
                return $this->path;
            }else{
                $this->fileerror="上传失败";
            }
        }else{
            exit("<b>".$this->fileerror."</b>");
        }
    }
}
?>

调用很简单，在文件上传检查的PHP页面加入：

    $u=new upload();
    $a=$u->uploads();
    $c=$u->Smallimg();
    echo "<a href='$a'><img src='$c' /></a>"