CakePHP에서 양식 유효성 검사를 사용하는 방법은 무엇입니까?

$ bin/cake bake model User

// src/Model/Entity/User.php

namespace AppModelEntity;

use CakeORMEntity;

class User extends Entity
{
    protected $_accessible = [
        '*' => true,
        'id' => false,
    ];

    protected function _setPassword($password)
    {
        return (new DefaultPasswordHasher)->hash($password);
    }

    protected function _getFullName()
    {
        return $this->_properties['first_name'] . ' ' . $this->_properties['last_name'];
    }

    protected function _getAge()
    {
        $now = new DateTime();
        $birthDate = new DateTime($this->_properties['birth_date']);

        return $now->diff($birthDate)->y;
    }

    protected function _setAge($age)
    {
        $this->_properties['birth_date'] = (new DateTime("-$age years"))->format('Y-m-d');

        return $age;
    }

    protected function _validationDefault(Validator $validator)
    {
        $validator
            ->notEmpty('username', 'A username is required')
            ->notEmpty('password', 'A password is required')
            ->add('password', [
                'length' => [
                    'rule' => ['minLength', 8],
                    'message' => 'Password must be at least 8 characters long',
                ]
            ])
            ->notEmpty('first_name', 'A first name is required')
            ->notEmpty('last_name', 'A last name is required')
            ->add('email', 'valid-email', [
                'rule' => 'email',
                'message' => 'Please enter a valid email address'
            ]);

        return $validator;
    }
}

// src/Template/Users/add.ctp

<?= $this->Form->create($user) ?>
<?= $this->Form->input('username') ?>
<?= $this->Form->input('password') ?>
<?= $this->Form->input('first_name') ?>
<?= $this->Form->input('last_name') ?>
<?= $this->Form->input('email') ?>
<?= $this->Form->button(__('Submit')) ?>
<?= $this->Form->end() ?>

// src/Controller/UsersController.php

namespace AppController;

use CakeORMTableRegistry;

class UsersController extends AppController
{
    public function add()
    {
        $user = $this->Users->newEntity();

        if ($this->request->is('post')) {
            $user = $this->Users->patchEntity($user, $this->request->getData());

            if ($this->Users->save($user)) {
                $this->Flash->success(__('The user has been saved.'));

                return $this->redirect(['action' => 'index']);
            }

            $this->Flash->error(__('Unable to add the user.'));
        }

        $this->set('user', $user);
    }
}