管理java对象列表中的一个对象

我有一个对象列表，对象列表多次显示同一个对象，但所有重复对象的颜色字段都不同。我想改变反应

如果有人对此有解决方案，请创建通用方法并传递此列表，然后根据我的预期响应转换为

1.实际反应

[
    {
      "id": 21,
      "startDate": "2020-07-21",
      "startTime": "10:28:34+05:30",
      "endDate": "2020-07-21",
      "endTime": "19:28:34+05:30",
      "eventName": "Stretegic Planing for Business Success",
      "location": "America Phoenix",
      "city": "San Jose de Gracia",
      "eventImg": "Image Url",
      "passport": false,
      "passportDiscountPercent": 5,
      "featured": true,
      "myFavourite": true,
      "color": "Yellow"
    },
    {
      "id": 21,
      "startDate": "2020-07-21",
      "startTime": "10:28:34+05:30",
      "endDate": "2020-07-21",
      "endTime": "19:28:34+05:30",
      "eventName": "Stretegic Planing for Business Success",
      "location": "America Phoenix",
      "city": "San Jose de Gracia",
      "eventImg": "Image Url",
      "passport": false,
      "passportDiscountPercent": 5,
      "featured": true,
      "myFavourite": true,
      "color": "Green"
    },
    {
      "id": 76,
      "startDate": "2020-07-21",
      "startTime": "10:28:34+05:30",
      "endDate": "2020-07-21",
      "endTime": "19:28:34+05:30",
      "eventName": "Stretegic Planing for Business Success",
      "location": "string",
      "city": "Villa Juarez",
      "eventImg": "Imgage url",
      "passport": false,
      "passportDiscountPercent": 5,
      "featured": false,
      "myFavourite": true,
      "color": "Red"
    },
    {
      "id": 76,
      "startDate": "2020-07-21",
      "startTime": "10:28:34+05:30",
      "endDate": "2020-07-21",
      "endTime": "19:28:34+05:30",
      "eventName": "Stretegic Planing for Business Success",
      "location": "string",
      "city": "Villa Juarez",
      "eventImg": "Imgage url",
      "passport": false,
      "passportDiscountPercent": 5,
      "featured": false,
      "myFavourite": true,
      "color": "Black"
    }
]    

2.期待回应

[
    {
      "id": 21,
      "startDate": "2020-07-21",
      "startTime": "10:28:34+05:30",
      "endDate": "2020-07-21",
      "endTime": "19:28:34+05:30",
      "eventName": "Stretegic Planing for Business Success",
      "location": "America Phoenix",
      "city": "San Jose de Gracia",
      "eventImg": "Image Url",
      "passport": false,
      "passportDiscountPercent": 5,
      "featured": true,
      "myFavourite": true,
      "eventType": [
            {
              "color": "Yellow"
            },
            {
              "color": "Green"
            }
      ]
    },
    {
      "id": 76,
      "startDate": "2020-07-21",
      "startTime": "10:28:34+05:30",
      "endDate": "2020-07-21",
      "endTime": "19:28:34+05:30",
      "eventName": "Stretegic Planing for Business Success",
      "location": "string",
      "city": "Villa Juarez",
      "eventImg": "Imgage url",
      "passport": false,
      "passportDiscountPercent": 5,
      "featured": false,
      "myFavourite": true,
      "eventType": [
            {
              "color": "Red"
            },
            {
              "color": "Black"
            }
      ]
    }   
]    

---

步骤1:创建架构类

初始响应模型：

public class InitialModel {
            String id;
            String color;
}

public class Model {
        String id;
        List<Color> eventType = new ArrayList<>();

        class Color {
            String color;

            public Color(String color) {
                this.color = color;
            }
        }
    }

最终/转换响应模型：

public class InitialModel {
            String id;
            String color;
}

public class Model {
        String id;
        List<Color> eventType = new ArrayList<>();

        class Color {
            String color;

            public Color(String color) {
                this.color = color;
            }
        }
    }

1.我已添加了您的代码，但出现了一些错误

private List<EventCustomDTO> commonListView(List<EventDtoClass> eventDtoClassList) {
        List<EventCustomDTO> eventCustomDTOList = new ArrayList<>();
        List<EventDtoClass> eventDtoClasses = new Gson().fromJson(eventDtoClassList.toString(), new TypeToken<List<EventCustomDTO>>(){}.getType());
        for (EventDtoClass eventDtoClass : eventDtoClasses) {
            EventCustomDTO eventCustomDTO = null;
            for(EventCustomDTO model : eventCustomDTOList){
                if(eventDtoClass.getId().equals(model.getId())){
                    eventCustomDTO = model;
                    break;
                }
            }
            if(eventCustomDTO == null) {
                eventCustomDTO = new EventCustomDTO();
                eventCustomDTO.getId() = eventDtoClass.getId();
                eventCustomDTOList.add(eventCustomDTO);
            }
            eventCustomDTO.getEventType().add(new TypesOfEvents(eventDtoClass.getEvenTypeId(),eventDtoClass.getColor()));
        }
        return eventCustomDTOList;
    }

private List commonListView（List eventDtoClassList）{
List eventCustomDTOList=new ArrayList（）；
List eventDtoClasses=new Gson（）.fromJson（eventDtoClassList.toString（），new TypeToken（）{}.getType（））；
for（EventDtoClass EventDtoClass:EventDtoClass）{
EventCustomDTO EventCustomDTO=null；
for（EventCustomDTO模型：eventCustomDTOList）{
if（eventDtoClass.getId（）.equals（model.getId（）））{
eventCustomDTO=模型；
打破
}
}
if（eventCustomDTO==null）{
eventCustomDTO=新的eventCustomDTO（）；
eventCustomDTO.getId（）=eventDtoClass.getId（）；
添加（eventCustomDTO）；
}
eventCustomDTO.getEventType（）.add（新类型的事件（eventDtoClass.GetEventTypeId（），eventDtoClass.getColor（））；
}
returneventcustomdtolist；
}

由于预期结果中有不同的JSON，因此需要有两个类进行序列化/反序列化。让我们考虑下面的类：

@Getter
@AllArgsConstructor
private class ObjectA {
    public Long id;
    public String color;
}

@ToString
@AllArgsConstructor
private class ObjectB {
    public Long id;
    public String eventType;
}

在这种情况下，获得预期结果的代码如下：

List<ObjectA> object = List.of(new ObjectA(1L, "green"), new ObjectA(1L, "red"), new ObjectA(2L, "yellow"));
object.stream().collect(Collectors.groupingBy(ObjectA::getId))
        .entrySet() // from map of grouped ObjectA's
        .stream()
        .map(entry -> new ObjectB(entry.getKey(), // GroupID
                                  entry.getValue() // list of grouped ObjectA's by current GroupID
                                         .stream()
                                         .map(ObjectA::getColor) // change to stream of all color strings from grouped ObjectA's by current GroupID
                                         .collect(Collectors.joining(", ")))
        ).forEach(System.out::println);
        //.collect(Collectors.toList());

---

您可以根据您的用例简单地调整代码。

如果已经找到模型，这不是要添加两次吗？我认为你应该添加modelList.add（tempModel）；持续对于空检查？jsonString上放了什么？jsonString是java字符串格式的实际响应JSON。此行中的错误是：eventCustomDTO.getId（）=eventDtoClass.getId（）；变量expectedI需要传递列表而不是jsonString

ObjectB(id=1, eventType=green, red)
ObjectB(id=2, eventType=yellow)