nil：NilClass的未定义方法“ microposts”

我正在阅读Michal Hart的教程并研究Rails4。我花了几个小时来解决这个问题。

user_controller.erb：

class UsersController < ApplicationController
def show
    @user = current_user
    @microposts = @user.microposts
  end
end

micopost_controller.erb：

class MicropostsController < ApplicationController



 def create
    @micropost = Micropost.create(micropost_params)

  end

  private
  def micropost_params
    params.require(:micropost).permit(:content) if params[:micropost]

  end

end

show.html.erb：

<h2>Users Post</h2>
<% if @user.microposts.any? %>
    <table class="microposts" summary="User microposts">
        <%= render @microposts %>
    </table>

_micropost.html.erb：

<tr>
<td class="micropost">
        <span class="content">
            <%= micropost.content %>
        </span>
        <span class="timestamp">
            Posted <%= time_ago_in_words(micropost.created_at) %> ago.
        </span>
    </td>
</tr>

甚至“ undefined method`microposts' ”也帮不了我。

任何帮助将不胜感激。