Laravel框架validate的用法

use Illuminate\Support\Facades\Validator;

public function demoValidate(Request $request)
{
    $input = $request->input();
    $validator = $this->validate($input);

    if ($validator->fails()) {
        echo "<pre>";
        print_r($validator->getMessageBag()->all());
        exit();
    }
}

private function validate($input)
{
    $rules = [
        'merchantId' => 'required|integer',

    ];
    $message = [
        'merchantId.required' => '商家ID必传',
        'merchantId.integer'  => '商家ID必须为int',

    ];
    return Validator::make($input, $rules, $message);
}