Laravel Class App \ Http \ Composers \ MainComposer不存在

Question

我是laravel的新人，我需要一些laravel 5的帮助，为什么这个错误呢？错误发生在Composer类和ComposerServiceProvider中

MainComposer类

<?php
namespace App\Htt\Composers;
use Illuminate\Contracts\View\View;
use App\Category;


class MainComposer {
    public function compose(View $view){
        $view->with('categories', Category::all());
    }
}

ComposerServiceProvider.php

 <?php
namespace App\Providers;
use View; // its saing class View does not exist
use Illuminate\Support\ServiceProvider;
class ComposerServiceProvider extends ServiceProvider{
    public function boot(){
        View::composer('*', 'App\Http\Composers\MainComposer');
    }

    public function register(){

    }

}