Jackson serialization: how to ignore superclass properties

Question

I want to serialize a POJO class which is not under my control, but want to avoid serializing any of the properties which are coming from the superclass, and not from the final class. Example:

public class MyGeneratedRecord extends org.jooq.impl.UpdatableRecordImpl<...>,     example.generated.tables.interfaces.IMyGenerated {   public void setField1(...);   public Integer getField1();    public void setField2(...);   public Integer getField2(); ... } 

You can guess from the example that that this class is generated by JOOQ, and inherits from a complex base class UpdatableRecordImpl which also has some bean property-like methods, which cause problems during the serialization. Also, I have several similar classes, so it would be good to avoid duplicating the same solution for all of my generated POJOs.

I have found the following possible solutions so far:

• ignore the specific fields coming from superclass using mixin technique like this: How can I tell jackson to ignore a property for which I don't have control over the source code?

  The problem with this is that if the base class changes (e.g., a new getAnything() method appears in it), it can break my implementation.

• implement a custom serializer and handle the issue there. This seems a bit overkill to me.

• as incidentally I have an interface which describes exactly the properties I want to serialize, maybe I can mixin a @JsonSerialize(as=IMyGenerated.class) annotation...? Can I use this for my purpose?

But, from pure design point of view, the best would be to be able to tell jackson that I want to serialize only the final class' properties, and ignore all the inherited ones. Is there a way to do that?

Thanks in advance.

Answer 1

You can register a custom Jackson annotation intropector which would ignore all the properties that come from the certain super type. Here is an example:

public class JacksonIgnoreInherited {      public static class Base {         public final String field1;          public Base(final String field1) {             this.field1 = field1;         }     }      public static class Bean extends Base {         public final String field2;          public Bean(final String field1, final String field2) {             super(field1);             this.field2 = field2;         }     }      private static class IgnoreInheritedIntrospector extends JacksonAnnotationIntrospector {         @Override         public boolean hasIgnoreMarker(final AnnotatedMember m) {             return m.getDeclaringClass() == Base.class || super.hasIgnoreMarker(m);         }     }      public static void main(String[] args) throws JsonProcessingException {         final ObjectMapper mapper = new ObjectMapper();         mapper.setAnnotationIntrospector(new IgnoreInheritedIntrospector());         final Bean bean = new Bean("a", "b");         System.out.println(mapper                         .writerWithDefaultPrettyPrinter()                         .writeValueAsString(bean));     }  } 

Output:

{ "field2" : "b" }