Laravel 将 JSON 转换为数组

我正在try 将JSON字段转换为array.例如，模型如下所示:

protected $casts = [
    'content' => 'array'
]; 

在插入内容时，我是这样做的:

'content'=> json_encode([
                'description' => $faker->paragraph(3),
                'about' => $faker->paragraph(2),
                'info' => $faker->paragraph(2),
                'updated' => $faker->dateTimeBetween('-1 years', 'now')
]),

但在获取数据时，它只打印一个字符串，其他什么都不打印.

The migration in this part looks like this:

$campaign->json('content');

Sample of the output:

"content": "{\"description\":\"Ut quas quo odio illo. Voluptates quia fuga itaque sint. Velit sapiente fugit ea ut ducimus sint tempora eligendi. Ea et molestiae consequuntur quibusdam soluta voluptatem.\",\"about\":\"Aut voluptates et iste ut perspiciatis. Esse sunt ullam inventore sit doloremque et quisquam.\",\"info\":\"Corrupti et facere exercitationem consequatur aspernatur quo saepe. Omnis et tempore enim ut. Quia magnam quia enim et eos enim.\",\"updated\":{\"date\":\"2015-11-22 08:25:13.000000\",\"timezone_type\":3,\"timezone\":\"UTC\"}}",

Any ideas why?