中心菜单的元素navbar Bootstrap 4

Question

我想将导航栏中的所有元素移动到中心。我该怎么做？

我还希望将所有物品都传播给竞争者。这就是我想要达到的目标：

这是我的菜单代码：

<header>
    <div class="container">
        <nav class="navbar navbar-toggleable-md navbar-light bg-faded">
          <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
            <span class="navbar-toggler-icon"></span>
          </button>
          <a class="navbar-brand" href="#">Navbar</a>
          <div class="collapse navbar-collapse" id="navbarNav">
              <ul class="navbar-nav mx-auto">
                <li class="nav-item active text-center">
                  <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
                </li>
                <li class="nav-item text-center">
                  <a class="nav-link" href="#">Features</a>
                </li>
                <li class="nav-item text-center">
                  <a class="nav-link" href="#">Pricing</a>
                </li>
                <li class="nav-item dropdown text-center">
                  <a class="nav-link dropdown-toggle" href="http://example.com" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
                    Dropdown link
                  </a>
                  <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
                    <a class="dropdown-item" href="#">Action</a>
                    <a class="dropdown-item" href="#">Another action</a>
                    <a class="dropdown-item" href="#">Something else here</a>
                  </div>
                </li>
              </ul>
          </div>
        </nav>
    </div>
</header>

我已经尝试过这个解决方案，但没有任何问题： Centering the navbar content in Bootstrap 4 (alpha 5)