use Illuminate\Support\Facades\Validator;

public function store(Request $request)
{
    $validator = Validator::make($request->all(), [
        'title' => 'required|unique:posts|max:255',
        'body' => 'required',
    ]);
    
    // 第一次验证
    if ($validator->fails()) {
        return redirect('post/create')
            ->withErrors($validator)
            ->withInput();
    }
    
    // 稍后在方法中重用
    $validator->validate(); // 会再次验证
    
    // 创建文章...
}

php artisan make:request StorePostRequest

public function rules()
{
    return [
        'title' => 'required|unique:posts|max:255',
        'body' => 'required',
    ];
}

public function store(StorePostRequest $request)
{
    // 验证已自动完成，可以直接使用数据
    $validated = $request->validated();
    
    // 创建文章...
}

namespace App\Traits;

trait PostValidationTrait
{
    protected function validatePostData(array $data)
    {
        return Validator::make($data, [
            'title' => 'required|unique:posts|max:255',
            'body' => 'required',
        ]);
    }
}

use App\Traits\PostValidationTrait;

class PostController extends Controller
{
    use PostValidationTrait;
    
    public function store(Request $request)
    {
        $validator = $this->validatePostData($request->all());
        
        if ($validator->fails()) {
            // 处理错误
        }
        
        // 创建文章...
    }
}