Read JSON with Jersey 2.0 (JAX-RS 2.0) - json

Question

I was using Jersey 1.16 to consume a JSON, but now I'm with difficulties to consume a JSON using Jersey 2.0 (that implements JAX-RS 2.0).
I have a JSON response like this:
{
"id": 105430,
"version": 0,
"cpf": "55443946447",
"email": "maria#teste.br",
"name": "Maria",
}
and the method that consumes it:
public static JSONObject get() {
String url = "http://127.0.0.1:8080/core/api/person";
URI uri = URI.create(url);
final Client client = ClientBuilder.newClient();
WebTarget webTarget = client.target(uri);
Response response = webTarget.request(MediaType.APPLICATION_JSON).get();
if (response.getStatus() == 200) {
return response.readEntity(JSONObject.class);
}
}
I also tried:
return webTarget.request(MediaType.APPLICATION_JSON).get(JSONObject.class);
But the jSONObject return is null. I don't understand my error because the response is OK!

Answer 1

This is how to use the Response type correctly:
private void getRequest() {
Client client = ClientBuilder.newClient();
String url = "http://localhost:8080/api/masterdataattributes";
WebTarget target = client.target(url);
Response res = target
.request(MediaType.APPLICATION_JSON)
.get();
int status = res.getStatus();
String json = res.readEntity(String.class);
System.out.println(String.format("Status: %d, JSON Payload: %s", status, json));
}
If you're just interested in the payload, you could also just issue a get(String.class). But usually you will also want to check the response status, so working with the Response is usually the way to go.
If you want a typed (generic) JSON response, you could also have readEntity return a Map, or a list of Map if the response is an array of objects as in this example:
List<Map<String, Object>> json = res.readEntity(new GenericType<List<Map<String, Object>>>() {});
String id = (String) json.get(0).get("id");
System.out.println(id);

Answer 2

I have found the solution. Maybe it is not the best of, but it works.
public static JsonObject get() {
String url = "http://127.0.0.1:8080/core/api/person";
URI uri = URI.create(url);
final Client client = ClientBuilder.newClient();
WebTarget webTarget = client.target(uri);
Response response = webTarget.request(MediaType.APPLICATION_JSON).get();
//Se Response.Status.OK;
if (response.getStatus() == 200) {
StringReader stringReader = new StringReader(webTarget.request(MediaType.APPLICATION_JSON).get(String.class));
try (JsonReader jsonReader = Json.createReader(stringReader)) {
return jsonReader.readObject();
}
}
return null;
}
I switched the class JSONObject (package import org.codehaus.jettison) by JsonObject (package javax.json) and I used the methods to manipulate the content as String.
S.

Answer 3

mmey answer is the correct and optimal one, instead of invoking the service twice it does it one time.