一、创建中间件设置Accept 头
生成中间件
php artisan make:middleware AcceptHeader
设置Accept头
<?php
namespace App\Http\Middleware;
use Closure;
class AcceptHeader
{
    public function handle($request, Closure $next)
    {
        $request->headers->set('Accept', 'application/json');
        return $next($request);
    }
}
将中间件添加到api中间件组中
protected $middlewareGroups = [
        'web' => [
       .
       .
       .
        ],
        'api' => [
            \App\Http\Middleware\AcceptHeader::class,
            'throttle:60,1',
            \Illuminate\Routing\Middleware\SubstituteBindings::class,
        ],
    ];