1、建立中间件Cors.php
命令：php artisan make:middleware Cors
在/app/Http/Middleware/ 目录下会出现一个Cors.php 文件。
2、在handle 方法中加入如下内容
$response = $next($request);
$response->header('Access-Control-Allow-Origin', '*');
$response->header('Access-Control-Allow-Headers', 'Origin, Content-Type, Cookie, Accept, multipart/form-data, application/json');
$response->header('Access-Control-Allow-Methods', 'GET, POST, PATCH, PUT, OPTIONS');
$response->header('Access-Control-Allow-Credentials', 'false');
return $response;
3、在 Kernel.php文件中的$middleware中加入刚刚添加的中间件：\App\Http\Middleware\Cors::class,
protected $middleware = [
\Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class,
\App\Http\Middleware\EncryptCookies::class,
\Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
\Illuminate\Session\Middleware\StartSession::class,
\Illuminate\View\Middleware\ShareErrorsFromSession::class,
\App\Http\Middleware\Cors::class,
];
