How to return a partial JSON response using Java?

If you use Jackson (a great JSON lib - kind of the standard for Java I believe), you may use the @View annotation to filter what you want in the resulting object.

I understand that you want something dynamic so it's a bit more complicated. You will find what you are looking for here: http://www.cowtowncoder.com/blog/archives/2011/02/entry_443.html (look at 6. Fully dynamic filtering: @JsonFilter).

I would be interested in the solution you will find.

Creating an ObjectMapper instance inside the resource method for every request can have significant performance overhead. According to the Jackson performance best practices object mappers are expensive to create.

Instead you can customize the JAX-RS provider's Jackson object writer inside the resource method using the Jackson 2.3 ObjectWriterModifier/ObjectReaderModifier feature.

Here is an example shows how to register an ObjectWriterModifier thread local object that changes the set of the filters applied for the JAX-RS Jackson provider being used inside a resource method. Note that I have not tested the code against an JAX-RS implementation.

public class JacksonObjectWriterModifier2 {    private static class FilterModifier extends ObjectWriterModifier {        private final FilterProvider provider;        private FilterModifier(FilterProvider provider) {            this.provider = provider;        }        @Override        public ObjectWriter modify(EndpointConfigBase<?> endpoint, MultivaluedMap<String, Object> responseHeaders,                                   Object valueToWrite, ObjectWriter w, JsonGenerator g) throws IOException {            return w.with(provider);        }    }    @JsonFilter("filter1")    public static class Bean {        public final String field1;        public final String field2;        public Bean(String field1, String field2) {            this.field1 = field1;            this.field2 = field2;        }    }    public static void main(String[] args) throws IOException {        Bean b = new Bean("a", "b");        JacksonJsonProvider provider = new JacksonJsonProvider();        ObjectWriterInjector.set(new FilterModifier(new SimpleFilterProvider().addFilter("filter1",                SimpleBeanPropertyFilter.filterOutAllExcept("field1"))));        provider.writeTo(b, Bean.class, null, null, MediaType.APPLICATION_JSON_TYPE, null, System.out);    }}

Output:

{"field1":"a"}

The Library jersey-entity-filtering Can do that :

https://github.com/jersey/jersey/tree/2.22.2/examples/entity-filtering-selectable

https://jersey.java.net/documentation/latest/entity-filtering.html

Exemple :

My Object

public class Address {    private String streetAddress;    private String region;    private PhoneNumber phoneNumber;}

URL

people/1234?select=streetAddress,region

RETURN

{   "streetAddress": "2 square Tyson",   "region": "Texas"}

Add to Maven

<dependency>    <groupId>org.glassfish.jersey.ext</groupId>    <artifactId>jersey-entity-filtering</artifactId>    <version>2.22.2</version></dependency>