Laravel试图将用户ID存储到posts表中

public function store(Request $request)
{
   $this->validate($request, array(
       'title' => 'required|max:255|min:2',
       'slug' => 'required|alpha_dash|unique:articles,slug',
       'category_id' => 'required|integer',
       'content' => 'required|min:2'
   ));

   $article = new Article;
   $article->title = $request->title;
   $article->slug = $request->slug;
   $article->category_id = $request->category_id;

   $article->content = $request->content;
   $article->save();

   Session::flash('success', 'Your article has been published.');
   return redirect()->route('article.show', $article->id);
}

There is a user_id column on the articles table,

This is my store function but when I create the post I am looking for a way to store the logged in user id to the user_id column in the articles table.

Get the authed user.

$article->user_id = Auth::user()->id;
$article->save();

Simple

$article->user_id = Auth::user()->id;

It will store the authenticated user id in the user_id field of your article table.

In your case change your Store code to

public function store(Request $request)
{
   $this->validate($request, array(
       'title' => 'required|max:255|min:2',
       'slug' => 'required|alpha_dash|unique:articles,slug',
       'category_id' => 'required|integer',
       'content' => 'required|min:2'
   ));

   $article = new Article;
   $article->title = $request->title;
   $article->slug = $request->slug;
   $article->category_id = $request->category_id;
   //it will store the current logged in user id in user_id field
   $article->user_id = Auth::user()->id;

   $article->content = $request->content;
   $article->save();

   Session::flash('success', 'Your article has been published.');
   return redirect()->route('article.show', $article->id);
}

But there is another method without using even the name space and all.

You can just fix this with the following code:

$article->user_id =  auth()->user()->id;

instead of:

$article->user_id = Auth::user()->id;