Yii2 basic版登录使用Yii::$app->user->login($user);出现错误

Yii2 basic版登录使用Yii::$app->user->login($user);出现错误Array to string conversion

1. MyAuthenticationController.php

<?php

namespace app\controllers;

use Yii;
use yii\web\Controller;
use app\models\User;

class MyAuthenticationController extends Controller
{
    public function actionIndex()
    {
        echo 'login success'; exit;
    }
    public function actionLogin()
    {
        $error = null;
        $username = Yii::$app->request->post('username',null);
        $password = Yii::$app->request->post('password',null);

        $user = User::findOne(['username'=>$username]);

        if(($username!=null)&&($password!=null))
        {
            if($user!=null){
                if($user->validatePassword($password)){
                    $this->redirect(['index']);//这里可以实现重定向
//                    Yii::$app->user->login($user);这是源代码，但是会出现“Array to string conversion”的错误，暂时还没有解决，所以使用上面的重定向代码来转向指定登录成功的页面
                }else{
                    $error = 'Password validation failed';
                }
            }else{
                $error = 'User not found';
            }
        }
        return $this->render('login',['error'=>$error]);
    }

    public function actionLogout()
    {
        Yii::$app->user->logout();
        return $this->redirect(['login']);
    }
}

1. app\models\User.php

<?php

namespace app\models;

use Yii;
use yii\base\NotSupportedException;
use yii\db\ActiveRecord;
use yii\web\IdentityInterface;


class User extends ActiveRecord implements IdentityInterface
{
    public static function tableName()
    {
        return 'user';
    }


    /**
     * @inheritdoc
     */
    public static function findIdentity($id)
    {
        return static::findOne(['id'=>$id]);
    }

    /**
     * @inheritdoc
     */
    public static function findIdentityByAccessToken($token, $type = null)
    {
        return static::findOne(['access_token'=>$token]);
    }

    /**
     * Finds user by username
     *
     * @param string $username
     * @return static|null
     */
    public static function findByUsername($username)
    {
        return static::findOne(['username'=>$username]);
    }

    /**
     * @inheritdoc
     */
    public function getId()
    {
        return $this->PrimaryKey();
    }

    /**
     * @inheritdoc
     */
    public function getAuthKey()
    {
        return $this->auth_Key;
    }

    /**
     * @inheritdoc
     */
    public function validateAuthKey($authKey)
    {
        return $this->getAuthKey() === $authKey;
    }

    /**
     * Validates password
     *
     * @param string $password password to validate
     * @return boolean if password provided is valid for current user
     */
    public function validatePassword($password)
    {
        return Yii::$app->security->validatePassword($password,$this->password_hash);
    }

    public function generateAuthKey()
    {
        $this->auth_key = Yii::$app->security->generateRandomKey();
    }

    public function beforeSave($insert)
    {
        if(parent::beforeSave($insert)){
            if($this->isNewRecord){
                $this->auth_key = \Yii::$app->security->generateRandomString();
            }
            return true;
        }
        return false;
    }
}

1. views\my-authentication\login.php

<?php
use \yii\bootstrap\ActiveForm;
use \yii\helpers\Html;
use \yii\bootstrap\Alert;
?>

<?php
if($error!=null){
    echo Alert::widget(['options'=>['class'=>'alert-danger'],'body'=>$error]);
};
?>

<?php if(Yii::$app->user->isGuest) { ?>
    <?php ActiveForm::begin() ?>

    <div class="form-group">
        <?php echo Html::label('Username','username'); ?>
        <?php echo Html::textInput('username','',['class'=>'form-control']);?>
    </div>

    <div class="form-group">
        <?php echo Html::label('Password','password'); ?>
        <?php echo Html::passwordInput('password','',['class'=>'form-control']); ?>
    </div>

    <?php echo Html::submitButton('Login',['class'=>'btn btn-primary']); ?>

    <?php ActiveForm::end(); ?>

<?php }  else {?>
    <h2>You are authentication!</h2>
    <br/><br/>
    <?php echo Html::a('logout',['my-authentication/logout'],['class'=>'btn btn-warning']); ?>
<?php } ?>

1. SQL

--
-- 表的结构 `user`
--

CREATE TABLE IF NOT EXISTS `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `username` varchar(255) NOT NULL,
  `auth_key` varchar(32) NOT NULL,
  `password_hash` varchar(255) NOT NULL,
  `access_token` varchar(100) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 AUTO_INCREMENT=2 ;

--
-- 转存表中的数据 `user`
--

INSERT INTO `user` (`id`, `username`, `auth_key`, `password_hash`, `access_token`) VALUES
(1, 'foo', '', '$2a$12$hL0rmIMjxhLqI.xr7jD1FugNWEgZNh62HuJj5.y34XBUfBWB4cppW', NULL);

用户名是foo，密码是foopassword,登录后在Yii::$app->user->login($user);时出现错误，

---

public function getId()
{
    return $this->getPrimaryKey();
}

不是 PrimaryKey