Jackson JSON List with Object Type

Question

I have to serialize JSON from a list of Objects. The resulting JSON has to look like this:

{
    \"status\": \"success\",
    \"models\": [
        {
                


        

Answer 1

This is an oldish question, But there is an arguably more idiomatic way of implementing this (I'm using jackson-databind:2.8.8):

Define a ModelSerializer (That extends StdSerializer as recommended by Jackson) that prints your model how you like and use the @JsonSerialize(contentUsing = ...) over your collection type:

class ModelSerializer extends StdSerializer {

    public ModelSerializer(){this(null);}
    public ModelSerializer(Class t){super(t);} // sets `handledType` to the provided class

    @Override
    public void serialize(List value, JsonGenerator jgen,
            SerializerProvider provider) throws IOException,
            JsonProcessingException {
        jgen.writeStartObject();
        jgen.writeObjectField("model", value);
        jgen.writeEndObject();
    }
}

Meanwhile, in another file:

class SomethingWithModels {
    // ...
    @JsonSerialize(contentUsing = ModelSerializer.class)
    private Collection models;
    // ...
}

Now you aren't bound to just Lists of models but may apply this to Collections, Sets, Native []s and even the values of Maps.