model：

use Yii;

/**
 * 获取头像url地址
 * @return 头像的url地址
 */
public function getPortraitUrl()
{
    return self::getAvatarUrlById($this->id);
}

/**
 * 获取头像存放路径
 * @return 头像的存放路径
 */
public static function getAvatarPathById($companyId)
{
    $string = str_pad($companyId, 6, ‘0‘, STR_PAD_LEFT);
    $path = ‘company/‘ . substr($string, 0, -4) . ‘/‘ . substr($string, -4, 2) . ‘/‘ . substr($string, -2, 2) . image_type_to_extension(IMAGETYPE_JPEG);;
    return $path;
}

/**
 * 通过用户ID获取头像url地址
 */
public static function getAvatarUrlById($companyId)
{
    $path = self::getAvatarPathById($companyId);
    $file = Yii::getAlias(‘@uploadPath/‘ . $path);
    if (file_exists($file)) {
        $makeTime = filemtime($file);
        return Yii::getAlias(‘@uploadUrl/‘ . $path) . ‘?‘ . $makeTime;
    }
    return Yii::getAlias(‘@resUrl/‘ . self::DEFAULT_AVATAR);
}

控制器：

use Yii;
use app\models\Company;
use yii\helpers\FileHelper;
use yii\web\Controller;
use yii\web\UploadedFile;

public function actionProfile()
{
    $id = Yii::$app->session[‘companyId‘];//得到id
    $model = Company::findOne($id);
    $imageUpload = UploadedFile::getInstance($model, ‘imageUpload‘);//返回一个上传文件
    if (Yii::$app->request->isPost && $model->load(Yii::$app->request->post())) {//判断是否post提交，加载数据
        if ($imageUpload && $model->validate([‘imageUpload‘])) {//数据验证
            $path =  Company::getAvatarPathById($id);//图片的路径别名
            $avatarImage = Yii::getAlias(‘@uploadPath/‘ . $path);//将路径别名转化为实际的路径
            FileHelper::createDirectory(dirname(Yii::getAlias($avatarImage)));//创建目录
            $imageUpload->saveAs(Yii::getAlias($avatarImage));//保存图片
        }
        if($model->save()) {
            Yii::$app->session[‘companyName‘] = $model->name;
        }
    }
    return$this->render(‘profile‘, [‘model‘ => $model]);
}

视图显示：

use app\models\Company;

<?= $form->field($model, ‘imageUpload‘)->fileInput([‘maxlength‘ => true])->hint(‘建议上传尺寸:100*100--300*300‘) ?>

<?= $form->field($model, ‘imageUpload‘, [‘inputTemplate‘=>‘<img src="http://www.mamicode.com/‘./app/models/Company::getAvatarUrlById($model->id).‘" width="100px" height="100px" />‘])->staticControl() ?>

结果显示：
网页显示

本地显示 （当前ID.jpeg）

       

yii2.0上传图片