How to add No Argument Constructor to Java class from another package?-CodePudding

I'm trying to read a json file and convert to Object and this works fine for other classes but in this case my model has GeoJsonMultiPolygon which is from package org.springframework.data.mongodb.core.geo; and does not contain a constructor with no arguments

Caused by: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `org.springframework.data.mongodb.core.geo.GeoJsonMultiPolygon` (no Creators, like default constructor, exist): cannot deserialize from Object value (no delegate- or property-based Creator)


at [Source: (BufferedInputStream); line: 12, column: 5] (through reference chain: java.util.ArrayList[0]->data.countryboundaries.CountryBoundaries["geometry"])

Model:

@Getter
@Setter
@ToString()
@EqualsAndHashCode
@Builder
@AllArgsConstructor
@NoArgsConstructor
@JsonIgnoreProperties(ignoreUnknown = true)
@Document(collection = "country-boundaries")
public class CountryBoundaries {
    @Id
    private String id;
    @EqualsAndHashCode.Exclude
    private String type;
    @EqualsAndHashCode.Exclude
    private CountryBoundariesProperties properties;
    @EqualsAndHashCode.Exclude
    private GeoJsonMultiPolygon geometry;
}

Code:

ObjectMapper mapper = new ObjectMapper();
        InputStream is = Country.class.getResourceAsStream("/country-boundaries.json");
        List<CountryBoundaries> countryBoundaries = mapper.readValue(is,  new TypeReference<>(){});
        countryBoundariesRepository.saveAll(countryBoundaries);

How can I bypass this error since I'm not able to modify code from a library and fill the geometry object using the ObjectMapper?

CodePudding user response：

Check static methods of GeoJsonModule. It contains modules containing serializers and deserializers for geo json classes.

ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(GeoJsonModule.geoJsonModule());

geoJsonModule() contains both serializers and deserializers, if you need only deserializers use deserializers().