自定義杰克遜反序列化器僅適用于嵌套類

我有一個vehicle這樣定義的Java類：

public final class Vehicle {

    private Integer id;
    private String description;
    private Location start;
    private Location end;
    private List<Integer> capacity;
    private List<Integer> skills;
    private TimeWindow timeWindow;
    private List<Break> breaks;

    public Vehicle(Integer id, String description, Location start,
                   Location end, List<Integer> capacity,
                   List<Integer> skills, TimeWindow timeWindow,
                   List<Break> breaks) {
        this.id = id;
        this.description = description;
        this.start = start;
        this.end = end;
        this.capacity = capacity;
        this.skills = skills;
        this.timeWindow = timeWindow;
        this.breaks = breaks;
    }

TimeWindow定義如下：

public final class Location {
    private final Double latitude;
    private final Double longitude;

    public Location(Double latitude, Double longitude) {
        this.latitude = latitude;
        this.longitude = longitude;
    }

現在，我得到的 JSON 沒有為位置（和）定義latitude和；此資訊僅編碼為一個陣列，請參見：longitudestartend

// vehicle.json
{
      "id" : 0,
      "description" : "vehicle 0",
      "start" : [
        12.304373066846503,
        51.62270653765847
      ],
      "end" : [
        12.304373066846503,
        51.62270653765847
      ],
      "capacity" : [
        9
      ],
      "skills" : [
      ],
      "time_window" : [
        1644188400,
        1644274800
      ],
      "breaks" : [
      ]
}

在這種情況下，我該如何撰寫一個自定義反序列化器Location（與 相同的問題TimeWindow）？如果可能，我不想為整個Vehicle班級撰寫自定義反序列化器。

我試過這個：

@JsonDeserialize(
        using = LocationJsonDeserializer.class
)
public final class Location {
// ....

public class LocationJsonDeserializer extends JsonDeserializer<Location> {

    @Override
    public Location deserialize(JsonParser p, DeserializationContext ctxt) {

        final var longitude = 0d;
        final var latitude = 0d;

        // what to do here? 
        return new Location(latitude, longitude);
    }

在我看來，我將整個Vehicle傳遞到我的deserialize方法中，而不僅僅是Location部分。我在這里做錯了嗎？這種方法使用杰克遜可行嗎？

uj5u.com熱心網友回復：

您可以Vehicle使用@JsonCreator標記和Double[]用于引數的類start和end. 您還需要@JsonProperty為每個引數添加標簽。

這是一個示例，為簡單起見，我沒有包含引數time_window和breaks.

@JsonCreator
public Vehicle(@JsonProperty("id") Integer id, 
        @JsonProperty("description") String description,
        @JsonProperty("start") Double[] start, 
        @JsonProperty("end") Double[] end,
        @JsonProperty("capacity") List<Integer> capacity, 
        @JsonProperty("skills") List<Integer> skills) {
    this(id, description, new Location(start[0], start[1]), 
            new Location(end[0], end[1]), capacity, skills);
}

使用json不帶引數的問題中的time_window和進行測驗breaks：

String result = "{\"id\":0,\"description\":\"vehicle 0\",\"start\":[12.304373066846503,51.62270653765847],\"end\":[12.304373066846503,51.62270653765847],\"capacity\":[9],\"skills\":[]}";

ObjectMapper mapper = new ObjectMapper();

Vehicle vehicle = mapper.readValue(result, Vehicle.class);

String json = mapper.writerWithDefaultPrettyPrinter().writeValueAsString(vehicle);

System.out.println(json);

輸出：

{
  "id" : 0,
  "description" : "vehicle 0",
  "start" : {
    "latitude" : 12.304373066846503,
    "longitude" : 51.62270653765847
  },
  "end" : {
    "latitude" : 12.304373066846503,
    "longitude" : 51.62270653765847
  },
  "capacity" : [ 9 ],
  "skills" : [ ]
}

標籤：爪哇 json 序列化 杰克逊 json反序列化

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