kindeditor 上传图片失败,该怎么解决

<br />    <script><br />    var editor;<br />        KindEditor.ready(function(K) {<br />            editor = K.create('textarea[name="body"]', {<br />                allowFileManager : true,<br />                urlType : 'absolute',<br />                uploadJson:'{:U('News/uploads')}',<br />            });<br />        });    <br />    </script><br />

<br />    {"error":0,"url":"Uploads/Allimg/2014-05-29/5386b82a78de0.jpg"}<br />

<br />    public function uploads(){                <br />            $upload = new \Think\Upload();<br />            $upload->maxSize = 3145728 ;<br />            $upload->exts = array('jpg', 'gif', 'png', 'jpeg');<br />            $upload->rootPath = './Uploads/Allimg/'; <br />            $upload->savePath = '';<br />            $info = $upload->upload();            <br />            if($info){    <br />                $img_url = '/Uploads/Allimg/'.$info['imgFile']['savepath'].$info['imgFile']['savename'];<br />                echo json_encode(array('error' => 0, 'url' => $img_url));            <br />            }else{    <br />                // $upload->getError()<br />                echo json_encode(array('error' => 1, 'message' =>'上传失败'));            <br />            }<br />        }<br />