为什么在发出发布请求时用户名不会出现在我的负载中？

我想看到username和email它的是在我的有效载荷SQL数据库列列，但由于某种原因，它不会显示出来。我使用 React 作为前端，使用 Laravel 作为后端，出于某种原因，我没有看到它们。

我可能做错了什么？

这是User.php模型：

<?php

namespace App;

use Illuminate\Notifications\Notifiable;
use Illuminate\Contracts\Auth\MustVerifyEmail;
use Illuminate\Foundation\Auth\User as Authenticatable;

class User extends Authenticatable
{
    use Notifiable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'username', 'email', 'password',
    ];

/**
 * The attributes that should be hidden for arrays.
 *
 * @var array
 */
protected $hidden = [
    'password', 'remember_token',
];

/**
 * The attributes that should be cast to native types.
 *
 * @var array
 */
protected $casts = [
    'email_verified_at' => 'datetime',
];

public function posts() {
    return $this->hasMany(Post::class);
}
}

这是Posts.php模型：

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Post extends Model
{
    protected $fillable = ['body'];

    public function user() {
        $this->belongsTo(User::class);
    }

}

这是PostController.php：

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Post;

class PostController extends Controller
{
    public function create(Request $request, Post $post) {
        // create post
        $createdPost = $request->user()->posts()->create([
            'body' => $request->body
        ]);

        // return response
        return response()->json($createdPost);
    }
}

这是web.php：

Auth::routes();

Route::group(['middleware' => ['auth']], function () {
    Route::post('/posts', 'PostController@create');
});

这是我的帖子请求：

constructor(props) {
    super(props);
    this.state = {
        body: '',
        posts: []
    };
    this.handleSubmit = this.handleSubmit.bind(this);
    this.handleChange = this.handleChange.bind(this);
}

handleSubmit(e) {
    e.preventDefault();
    // this.postData();
    axios.post('/posts', {
        body: this.state.body
    }).then(response => {
        console.log(response);
        this.setState({
           posts: [...this.state.posts, response.data]
        });
    });

    this.setState({
        body: ''
    });
}