java - 迭代java8中的嵌套对象

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我是java8的新手。
我有以下课程。

class User {
  List<Vehicle> vehicle;
  private int vehiclecount;

  public List<Vehicle> getVehicle() {
        return vehicle;
  }
}

class Vehicle{
  String vehiclename;
  String vehiclecolor;
}

我可以将其保存在mongo集合中：

{ "_id" : ObjectId("59ca1e53a1a79607fcc9200f"), "_class" : "com.test.User",
   "vechicle" : [ { "vehiclename" : "Car", "vehiclecolor" : "Blue" } ],
   "count" : 1, "createdDate" : ISODate("2017-09-26T09:30:59.826Z") }

现在我基于Spring mongo数据存储库提取了结果。我想遍历上面的mongo集合，这样我只能得到车辆清单
我尝试了以下方法：

List<Vehicle> vehicle = result.stream().filter(vehicles->vehicles.getVehicle().stream().collect(Collectors.toList());

请帮助java8的即时消息。提前致谢

最佳答案

如果我正确理解：

List<Vehicle> vehicles =
    result.stream()
       .flatMap(user -> user.getVehicle().stream())
       .collect(Collectors.toList());