Return JSONArray instead of JSONObject, Jersey JAX-RS

Question

I am using Jersey to make some of my services RESTful.

My REST service call returns me

{\"param1\":\"value1\", \"param2\":\"value2\         


        

Answer 1

To return the entries in array-type style, you should build your entity from array. Try the following:

@GET
@Produces({MediaType.APPLICATION_JSON, MediaType.APPLICATION_JSON})
public Response getSomeList() {
    List<com.abc.def.rest.model.SimplePojo> yourListInstance = 
          new List<com.abc.def.rest.model.SimplePojo>();
    /* 
          Do something
    */
    return Response.ok(yourListInstance.toArray()).build();
}

if you face some trouble according to return type of toArray() method - you could explicitly cast your array:

Response
   .ok((com.abc.def.rest.model.SimplePojo[])yourListInstance.toArray())
   .build(); 

UPD: try to convert your list to JSONArray:

JSONArray arr = new JSONArray();
for (SimplePojo p : yourListInstance) {
  arr.add(p);
}

and then:

Response.ok(arr).build(); 

Answer 2

You can define your service method as follows, using Person POJO:

@GET
@Produces("application/json")
@Path("/list")
public String getList(){
    List<Person> persons = new ArrayList<>();
    persons.add(new Person("1", "2"));
    persons.add(new Person("3", "4"));
    persons.add(new Person("5", "6"));
    // takes advantage to toString() implementation to format as [a, b, c]
    return persons.toString();
}

The POJO class:

@XmlRootElement
public class Person {
    @XmlElement(name="fn")
    String fn;

    @XmlElement(name="ln")
    String ln;

    public Person(){        
    }

    public Person(String fn, String ln) {
        this.fn = fn;
        this.ln = ln;
    }    

    @Override
    public String toString(){
        try {
            // takes advantage of toString() implementation to format {"a":"b"}
            return new JSONObject().put("fn", fn).put("ln", ln).toString();
        } catch (JSONException e) {
            return null;
        }
    }
}

The results will look like:

[{"fn":"1","ln":"2"}, {"fn":"3","ln":"4"}, {"fn":"5","ln":"6"}]