De-serializing JSON to polymorphic object model using Spring and JsonTypeInfo annotation

Question

I have the following object model in my Spring MVC (v3.2.0.RELEASE) web application:

public class Order {
  private Payment payment;
}

@JsonTypeInfo(use = J         


        

Answer 1

The method registerSubtypes() works!

@JsonTypeInfo(use=JsonTypeInfo.Id.NAME, include=JsonTypeInfo.As.PROPERTY, property="type")
public interface Geometry {
  //...
}

public class Point implements Geometry{
  //...
}
public class Polygon implements Geometry{
  //...
}
public class LineString implements Geometry{
  //...
}

GeoJson geojson= null;
ObjectMapper mapper = new ObjectMapper();
mapper.disable(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES);
mapper.registerSubtypes(Polygon.class,LineString.class,Point.class);

try {
    geojson=mapper.readValue(source, GeoJson.class);            
} catch (IOException e) {
    e.printStackTrace();
}

Note1: We use the Interface and the implementing classes. I fyou want jackson to de-serialize the classes as per their implementing classes, you have to register all of them using ObjectMapper's "registerSubtypes" method.

Note2: In addition you use, " @JsonTypeInfo(use=JsonTypeInfo.Id.NAME, include=JsonTypeInfo.As.PROPERTY, property="type")" as annotation with your Interface.

You can also define the order of properties when mapper writes a value of your POJO as a json.

This you can do using below annotation.

@JsonPropertyOrder({"type","crs","version","features"})
public class GeoJson {

    private String type="FeatureCollection";
    private List features;
    private String version="1.0.0";
    private CRS crs = new CRS();
    ........
}

Hope this helps!