该上传接口放到controller里，返回的json格式是用于wangEditor编辑器的，非常好用上代码：

   /**
     * 上传图片
     */
    public function uploadPic($req)
    {
        
        $data = array (
            array(
                "name"=>"",
                "url" => "",
                "alt" => "",
                "href" => ""
            )
        );
        
        $file = $_FILES['images'];
            
        $rootPath = str_replace('\\','/',realpath(dirname(__FILE__).'/../../../'));
        
        if ($file) {
            
            //保存目录名
            $uploadPath = "/upload/images/" . date('Y-m-d', time());
            
            //随机文件名
            $randName = $this->getRandName();
            
        	//文件的扩展名
        	$ext = pathinfo($file['name'],PATHINFO_EXTENSION);
        	
        	//新文件名
        	$fileName = $randName. '.' . $ext;
        	
        	//目标文件路径
        	$dest = $rootPath . $uploadPath .'/' . $fileName;
        	
        	//文件夹不存在或者不是目录,创建文件夹
        	$folderPath = $rootPath . $uploadPath;
            if (!file_exists($folderPath) || !is_dir($folderPath)) {
                
                mkdir($folderPath, 0777, true);
            }
            //判断文件是否可写
            if (!is_writeable($folderPath)) {
                chmod($folderPath, 0777);
            }

            $data[0]['name'] = $fileName;
            $data[0]['url'] =  $uploadPath .'/' . $fileName;
            
            $tmp = $file['tmp_name'];
            
            if(is_uploaded_file($tmp)){
                
                if(move_uploaded_file($tmp,$dest)){
                    
                    $response = ['errno'=>0,'msg'=>'图片上传成功','data'=>$data];
                    exit(json($response));
                    
                }else{
                    $response = ['errno'=>-1,'msg'=>"图片上传失败",'data'=>$data];
                    exit(json($response));
                }
            }else{
                $response = ['errno'=>-1,'msg'=>"不是可上传文件",'data'=>$data];
                exit(json($response));
            }
            
        }
        
        $response = ['errno'=>-1,'msg'=>"图片上传失败",'data'=>$data];
        return json($response);
    }
    
    /**
     * 随机文件名
     */
    public function getRandName(){
    	$name = date('YmdHis');
    	for($i=0; $i<6; $i++){
    		switch(mt_rand(0,2)){
    			case 0:
    				$name .= chr(mt_rand(97,122));   //小a
    				break;
    			case 1:
    				$name .= chr(mt_rand(65,90));    //大A
    				break;
    			case 2:
    				$name .= mt_rand(0,9);          //获取随机数
    				break;
    		}
    	}
    	return $name;
    }