在bootstrap v4.3中，只需在<ul class="navbar-nav">中添加ml-auto 示例:<ul class="navbar-nav ml-auto">

只是从发布版4的一个getbootstrap页面复制了这个，它比上面的要好得多

<div class="d-none d-xl-block col-xl-2 bd-toc float-md-right">
    <ul class="section-nav">
         <li class="toc-entry toc-h2"><a href="#overview">Overview</a></li>
         <li class="toc-entry toc-h2"><a href="#classes">Classes</a></li>
         <li class="toc-entry toc-h2"><a href="#mixins">Mixins</a></li>
         <li class="toc-entry toc-h2"><a href="#responsive">Responsive</a></li>
    </ul>
</div> 

使用引导伸缩盒会有所帮助 我们来控制您的导航元素的位置和对齐。 对于上述问题，添加mr-auto是一个更好的解决方案。

<div id="app" 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="#navbarNavDropdown" aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <a class="navbar-brand" href="#">Navbar</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Features</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Pricingg</a>
      </li>
    </ul>
    <ul class="navbar-nav  " >
      <li  class="nav-item">
        <a class="nav-link" href="{{ url('/login') }}">Login</a>
      </li>
      <li  class="nav-item">
        <a class="nav-link" href="{{ url('/register') }}">Register</a>
      </li>
    </ul>
  </nav>
  @yield('content')
</div>

其他安置可能包括

fixed- top
    fixed bottom
    sticky-top

boostrap 4的变化很小。 要对齐导航栏右侧，你只需要做两个改变。 它们是:

在navbar-nav类添加w-100作为navbar-nav w-100使宽度为100 在nav-item下拉类中添加ml-auto作为nav-item下拉列表ml-auto使左侧空白为auto。

如果你不明白，请参考我附上的图片。

CodePen链接

完整源代码

<nav class="navbar navbar-expand-lg navbar-light bg-light">
  <a class="navbar-brand" href="#">Navbar</a>
  <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavDropdown" aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="navbarNavDropdown">
    <ul class="navbar-nav w-100">
      <li class="nav-item active">
        <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Features</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Pricing</a>
      </li>
      <li class="nav-item dropdown ml-auto">
        <a class="nav-link dropdown-toggle" href="#" 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>

如果你想要首页，功能和定价在左侧紧跟着你的nav-brand，然后登录和注册在右侧，然后包装两个列表在<div>和使用.justify-content-between:

<div class="collapse navbar-collapse justify-content-between">
<ul>....</ul>
<ul>...</ul>
</div>

对于Bootstrap 4 beta，元素对齐到右侧的示例导航栏是:

<div id="app" class="container">
  <nav class="navbar navbar-expand-md navbar-light bg-faded">
    <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbarNavDropdown" aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
      <span class="navbar-toggler-icon"></span>
    </button>
    <a class="navbar-brand" href="#">Navbar</a>
    <ul class="navbar-nav mr-auto">
      <li class="nav-item active">
        <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Features</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Pricingg</a>
      </li>
    </ul>
    <ul class="navbar-nav">
      <li class="nav-item">
        <a class="nav-link" href="{{ url('/login') }}">Login</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="{{ url('/register') }}">Register</a>
      </li>
    </ul>
  </nav>
</div>