Laravel 5.5中的FormRequest验证错误

Question

    // ValidationFormRequest.php
        public function rules()
        {
            return [
                'value' => 'required|numeric',
            ];
        }

    // web.php
    $this->group(['middleware' => ['auth'], 'namespace' => 'Admin', 'prefix' => 'admin'], function(){

        $this->get('transfer', 'BalanceController@transfer')->name('balance.transfer');
        $this->post('confirm-transfer', 'BalanceController@confirmTransfer')->name('confirm.transfer');
        $this->post('transfer', 'BalanceController@transferStore')->name('transfer.store');

    });

    // BalanceController.php

    public function transfer()
    {
         return view('admin.balance.transfer');
    }

    public function confirmTransfer(Request $request, User $user)
    {
        // ...

        return view('admin.balance.transfer-confirm', compact('sender', 'balance'));
    }

    public function transferStore(ValidationFormRequest $request)
    {
        // ...
    }

当源表单在web.php中没有路由时，如何使用FormRequest进行验证？

错误发生在路由“ transfer.store”中：

Symfony \组件\ HttpKernel \ Exception \ MethodNotAllowedHttpException没有消息

谢谢您的帮助。.......