composer require mongodb/mongodb

mongoManager = new Manager($this->getUri());
    $this->mongoCollection = new Collection($this->mongoManager, "mldn","dept");
  }
  public function test() {
    // 读取一条数据
    $data = $this->mongoCollection->findOne();
    print_r($data);
  }
  protected function getUri()
  {
    return getenv('MONGODB_URI') ?: 'mongodb://127.0.0.1:27017';
  }
}