反序列化：从自定义中获取数据class

Question

我正在尝试获取我从 Web 服务获取的 route, direction, longitude and latitude。我创建了 MapDataJSON class 以使用 'Gson' 库反序列化 json 字符串，但我不知道如何从 MapDataJSON 对象获取数据。如何从 MapDataJSSON class 获取数据 route, direction, latitude and longitude？

感谢任何帮助。

Json 字符串

[
  {
    "latitude": 20.123456,
    "longitude": 70.123456,
    "route": 4,
    "direction": "ABC"
   },

   {
    "latitude": 30.123456,
    "longitude": 80.123456,
    "route": 9,
    "direction": "DEF"
   },
     {
    "latitude": 10.123456,
    "longitude": 90.123456,
    "route": 3,
    "direction": "GHI"
   }

]

代码：

        Gson gson = new Gson();
        MapDataJSON[] data = gson.fromJson(sb.toString(),
                MapDataJSON[].class);

MapDataJSON class:

package com.json;

import java.util.ArrayList;

public class MapDataJSON {
    ArrayList<ItemDTO> items;

    public MapDataJSON(ArrayList<ItemDTO> items) {
        super();
        this.items = items;
    }

    public ArrayList<ItemDTO> getItems() {
        return items;
    }

    public void setItems(ArrayList<ItemDTO> items) {
        this.items = items;
    }

    public static class ItemDTO {
        double latitude;
        double longitude;
        int route;
        String direction;

        public ItemDTO(double latitude, double longitude, int route,
                String direction) {
            super();
            this.latitude = latitude;
            this.longitude = longitude;
            this.route = route;
            this.direction = direction;
        }

        public double getLatitude() {
            return latitude;
        }

        public double getLongitude() {
            return longitude;
        }

        public int getRoute() {
            return route;
        }

        public String getDirection() {
            return direction;
        }

        public void setLatitude(double latitude) {
            this.latitude = latitude;
        }

        public void setLongitude(double longitude) {
            this.longitude = longitude;
        }

        public void setRoute(int route) {
            this.route = route;
        }

        public void setDirection(String direction) {
            this.direction = direction;
        }
    }

}

Answer 1

只需更改您的代码以阻止下方。您不需要 MapDataJSON 来包装物品。

Gson gson = new Gson();
Type listType = new TypeToken<List<ItemDTO>>() {}.getType();
List<ItemDTO> data = gson.fromJson(json, listType);

for (ItemDTO itemDTO : data) {
    System.out.print(itemDTO.getLatitude());
}

反序列化：从自定义中获取数据class

Deserialization: get the data from the custom class

java

json

gson