php – Laravel验证：检查验证器失败的原因

$rules = array(
            'email_address' => 'required|email|unique:users,email','postal_code' => 'required|alpha_num',);

        $messages = array(
            'required' => 'The :attribute field is required','email' => 'The :attribute field is required','alpha_num' => 'The :attribute field must only be letters and numbers (no spaces)'
        );

        $validator = Validator::make(Input::all(),$rules,$messages);

        if ($validator->fails()) {

在外行人看来,我基本上想知道：“验证失败了,因为email_address不是唯一的吗？”