尝试运行$debugbarIsInstalled = class_exists(Debugbar::class)
当返回true时表示已安装Debugbar

您可以使用绑定方法查看它是否绑定到Laravel容器。

if (app()->bound('debugbar')) {
    // Now you can safely use Debugbar methods without the need to import a class that may or may not exists.
    app('debugbar')->startMeasure('render','Time for rendering');
    app('debugbar')->stopMeasure('render')
}