Question

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;
}

我可以将它保存在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") }

现在我根据spring mongo数据存储库提取结果。我想迭代上面的mongo集合，这样我才能获得车辆清单我尝试了下面的内容：

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

请帮助我刚接触java8。提前致谢

Answer 1

如果我理解正确：

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

在java8中迭代嵌套对象

1 个答案: