我自己写了一个Hash实现HashContract，在config里加载了provider，但是测试还是用了原来那个

1.
use Illuminate\Contracts\Hashing\Hasher as HashContract;
class MyHash implements HashContract {

/**
* Hash the given value.
*
* @param string $value
* @param array $options
* @return string
*/
public function make ($value, array $options = [ ])
{
// TODO: Implement make() method.
return md5($value);
}

2.
use Illuminate\Support\ServiceProvider;

class MyHashServiceProvider extends ServiceProvider {

/**
* Register the service provider.
*
* @return void
*/
public function register ()
{
// TODO: Implement register() method.
$this->app->singleton('hash',function(){
return new MyHash();
});
}
}
3.
config/app

'providers' => [
App\Service\MyHashServiceProvider::class,
/*

4.
dd(\Hash::make(1)); 输出是原来的加密