无法从 START_ARRAY 令牌中反序列化对象实例

Question

我有两个对象，一个是 Dashboard，第二个是 Room 我有一个 json 看起来像这样

  {
"hotel_id":"1",
"hotel_room":"200",
"hotel_properties":[{
        "id":"1",
        "room_type":"Single",
        "rack_rate":"2000",
        "publish_rate":"1800",
        "discount":"10",
        "availiable":"40",
        "total":"50"
      },
      {
        "id":"2",
        "room_type":"Double",
        "rack_rate":"4000",
        "publish_rate":"3600",
        "discount":"10",
        "availiable":"45",
        "total":"50"
      }
      ] 
  }

对象是

public class DashBoard {
    private int hotel_id;
    private int hotel_room;
    @JsonProperty("hotel_properties")
    private Room hotel_properties;
    }

还有一个物品室是这样的

public class Room { 
    private Long id;
    private String room_type;
    private String rack_rate;
    private String publish_rate;
    private String discount;
    private String availiable;
    private String total;
}

我隐藏所有构造函数，setter 和 getter 用于 Whosebug，但它在我的代码中我想使用此代码

从 URL 使用 ObjectMapper 将 Json 解析为对象

JsonReader jsonReader = new JsonReader();
        ObjectMapper mapper = new ObjectMapper();
        try {
            JSONObject json =  jsonReader.readJsonFromUrl("http://localhost/quinchy/json/dashboard.json");
            DashBoard dsh = mapper.readValue(json.toString(), DashBoard.class); 
            System.out.println(json.toString());
        } catch (IOException | JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

但是我得到这个错误

org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of Object out of START_ARRAY token

请帮我解决这个问题

Answer 1

从您发布的 JSON 字符串来看，似乎有一个包含 Room 个对象的列表。但是你使用了一个对象。

在您的 DashBoard class 中，尝试更改：

private Room hotel_properties;

至：

private List<Room> hotel_properties;

无法从 START_ARRAY 令牌中反序列化对象实例

Can not deserialize instance of Object out of START_ARRAY token

java

json

jackson

object-object-mapping

jsonobject