我在尝试反序列化以下类时遇到问题:
public class MetricValuesDto {
private Map<MetricType, MetricValueDto<?>> metricValues;
public MetricValuesDto() {
}
public MetricValuesDto(Map<MetricType, MetricValueDto<?>> metricValues) {
this.metricValues = metricValues;
}
public Map<MetricType, MetricValueDto<?>> getMetricValues() {
return metricValues;
}
public void setMetricValues(Map<MetricType, MetricValueDto<?>> metricValues) {
this.metricValues = metricValues;
}
}
我的通用抽象类:
public abstract class MetricValueDto<T> {
private T value;
private MetricTrend trend;
public MetricValueDto(T value, MetricTrend trend) {
this.value = value;
this.trend = trend;
}
public T getValue() {
return value;
}
public void setValue(T value) {
this.value = value;
}
public MetricTrend getTrend() {
return trend;
}
public void setTrend(MetricTrend trend) {
this.trend = trend;
}
}
我有两个实现 MetricValueDto
的具体类:
IntMetricValueDto:
public class IntMetricValueDto extends MetricValueDto<Integer> {
public IntMetricValueDto(Integer value, MetricTrend trend) {
super(value, trend);
}
}
FloatMetricValueDto:
public class FloatMetricValueDto extends MetricValueDto<Float> {
public FloatMetricValueDto(Float value, MetricTrend trend) {
super(value, trend);
}
}
知道反序列化 MetricValueDto 的正确策略是什么,以便我可以通过 ObjectMapper 解析它或 RestTemplate ?每当我运行时:
restTemplate.exchange("myEndpoint", HttpMethod.GET, entity, DataCollectionEventDto.class);
我明白了
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Can not construct instance of com.resson.dto.MetricValueDto: abstract types either need to be mapped to concrete types, have custom deserializer, or contain additional type information
DataCollectionEventDto:
public class DataCollectionEventDto {
private List<MapLayerDto> mapLayers;
@JsonUnwrapped
private MetricValuesDto metricValues;
public List<MapLayerDto> getMapLayers() {
return mapLayers;
}
public void setMapLayers(List<MapLayerDto> mapLayers) {
this.mapLayers = mapLayers;
}
public MetricValuesDto getMetricValues() {
return metricValues;
}
public void setMetricValues(MetricValuesDto metricValues) {
this.metricValues = metricValues;
}
@Override
public String toString() {
return ToStringBuilder.reflectionToString(this);
}
}
我基本上在网上尝试了所有的东西,但我无法让它工作;任何建议都会有所帮助。
最佳答案
使用 JsonSubTypes 注释和 JsonTypeInfo 来指示子类型。 property属性JsonTypeInfo用于区分不同的子类。
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "typ")
@JsonSubTypes({
@JsonSubTypes.Type(value = IntMetricValueDto.class, name = "INT"),
@JsonSubTypes.Type(value = FloatMetricValueDto.class, name = "FLT")})
public abstract class MetricValueDto<T> {
private T value;
private MetricTrend trend;
...
}
关于java - 通用抽象类的自定义 Jackson 反序列化,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/46413269/