Symfony2如何访问所有控制器中的一组数据？

I have searched but I can't find any similar issues or maybe I am phrasing it wrong. What I want to achieve is access to an object in all the controllers in my Bundle. For example:

<?php

namespace Example\CoreBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;

class FolderController extends Controller
{

    function indexAction()
    {

         $title = $this->folder->getTitle();
         $description = $this->folder->getDescription();

    }

}

Usually outside of Symfony I would have extended the Controller class myself with BaseController extends Controller and set this up in the construct method but I know Symfony doesn't use the construct method so I am a bit stuck as to where to go.

I would usually do something like this:

class BaseController extends Controller
{

     function __construct()
     {

          parent::__construct();
          //load up the folder from my model with an ID
          $this->folder = $folder;

     }

}

I would then extend BaseController from FolderController and go from there but I have tried this with Symfony and it does not work. I have looked into Services but do not think this is what I need to make this work. If any more details are required please let me know, thanks.

If I understand your question correctly, services are indeed what you're looking for.

First, define a service in services.yml:

services:
    vendor.folder_manager:
        class: Vendor\FolderBundle\Entity\Manager\FolderManager
        arguments:
            em: "@doctrine.orm.entity_manager"
            class: Vendor\FolderBundle\Entity\Folder

Then create that FolderManager class:

<?php
namespace Vendor\FolderBundle\Entity\Manager;

use Doctrine\ORM\EntityManager;
use Doctrine\ORM\EntityRepository;

class FolderManager
{
    protected $em;

    protected $repo;

    protected $class;

    public function __construct(EntityManager $em, $class) {
        $this->em = $em;
        $this->class = $class;
        $this->repo = $em->getRepository($class);
    }

    public function findById($id) {
        return $this->repo->findById($id);
    }

    public function getRepository() {
        return $this->repo;
    }
}

Finally, in your controller:

$this->container->get('vendor.folder_manager')->findById($folderId);

Or:

$this->container->get('vendor.folder_manager')->getRepository()->findById($folderId);

Symfony2 will automatically inject the entity manager the class into the manager, so all you have to provide in the controller is the folder's id.

Edit: To make it prettier, you could also make a shortcut function in your controller:

protected function getFolderManager()
{
    return $this->container->get('vendor.folder_manager');
}

Then you can do:

$this->getFolderManager()->findById($folderId);