symfony2：尝试从名称空间加载类“ Memcache”

Question

I using memcache with symfony2 and ratchet I installed memcache using this command line

sudo apt-get install php-memcache -y

I edited this lines on php.ini file

session.save_handler=memcache
session.save_path="localhost:11211"

but when i use this line

$memcache = new Memcache;

I get this error

symfony2: Attempted to load class "Memcache" from namespace 

my code socketcommand.php

<?php
namespace check\roomsBundle\Command;
use Ratchet\Session\SessionProvider;
use Symfony\Component\HttpFoundation\Session\Storage\Handler;
use Ratchet\App;
use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;

// Include ratchet libs
use Ratchet\Server\IoServer;
use Ratchet\Http\HttpServer;
use Ratchet\WebSocket\WsServer;
use Symfony\Bundle\FrameworkBundle\Command\ContainerAwareCommand;
// Change the namespace according to your bundle
use check\roomsBundle\Sockets\Chat;
use Doctrine\ORM\EntityManager;
use Symfony\Component\HttpFoundation\Session\Storage\Handler\MemcacheSessionHandler;
use Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage;

class SocketCommand extends ContainerAwareCommand
{
    protected function configure()
    {
        $this->setName('sockets:start-chat')
            // the short description shown while running "php bin/console list"
            ->setHelp("Starts the chat socket demo")
            // the full command description shown when running the command with
            ->setDescription('Starts the chat socket demo')
        ;
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $output->writeln([
            'Chat socket',// A line
            '============',// Another line
            'Starting chat, open your browser.',// Empty line
        ]);
        $memcache = new Memcache;
        $memcache->connect('localhost', 11211);

        $session = new SessionProvider(
            new Chat(new MyApp(), $this->getContainer()),
            new Handler\MemcacheSessionHandler($memcache)
        );

        $server = new App('localhost');
        $server->route('/sessDemo', $session);
        $server->run();
    }

}

my chat.php

<?php
namespace check\roomsBundle\Sockets;
use tuto\testBundle\Entity\Users;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Request;
use Ratchet\WebSocket\WsServerInterface;
use Ratchet\MessageComponentInterface;
use Ratchet\ConnectionInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Doctrine\ORM\EntityManager;
use Symfony\Component\DependencyInjection\ContainerInterface as Container;
use Symfony\Component\HttpFoundation\Session\Session;


class Chat extends Controller implements MessageComponentInterface, WsServerInterface
{
    protected $container;
    protected $clients;

    //protected $em;

    //protected $db;
    public function __construct(ContainerInterface $container) {
        $this->clients = new \SplObjectStorage;
        $this->container = $container;


        //$this->em = $em;
        //$this->container = $container;
        //$this->em = $em;
    }

    public function onOpen(ConnectionInterface $conn) {
        $this->clients->attach($conn);

        if (!isset ($conn->Session) || !$conn->Session instanceof Session) {
            throw new \RuntimeException('Session is not defined. Make sure that SessionProvider is executed before FOSUserProvider.');
        }
        try {
            $token      = unserialize($conn->Session->get('_security_main'));
            $user       = $token->getUser();
            $provider   = $this->_container->get('fos_user.user_provider.username');
            $conn->User = $provider->refreshUser($user);
        } catch (Exception $ex) {
            $conn->User = null;
        }
    }

Answer 1

replace this line $memcache = new Memcache;

with this $memcache = new \\Memcache;