How to send/accept JSON using JerseyTest Framework - json

Question

I am attempting to write a simple test class that emulates a RESTful Web Service creating a Customer via a POST method. The following fails at assertEquals, I receive a 400 Bad Request response. I cannot use debugger to observe stack trace. However the console tells me the following...
INFO: Started listener bound to [localhost:9998]
INFO: [HttpServer] Started.
public class SimpleTest extends JerseyTestNg.ContainerPerMethodTest {
public class Customer {
public Customer() {}
public Customer(String name, int id) {
this.name = name;
this.id = id;
}
#JsonProperty("name")
private String name;
#JsonProperty("id")
private int id;
}
#Override
protected Application configure() {
return new ResourceConfig(MyService.class);
}
#Path("hello")
public static class MyService {
#POST
#Consumes(MediaType.APPLICATION_JSON)
public final Response createCustomer(Customer customer) {
System.out.println("Customer data: " + customer.toString());
return Response.ok("customer created").build();
}
}
#Test
private void test() {
String json = "{" +
"\"name\": \"bill\", " +
"\"id\": 4" +
"}";
final Response response = target("hello").request(MediaType.APPLICATION_JSON_TYPE).post(Entity.json(json));
System.out.println(response.toString());
assertEquals(response.getStatus(), 200);
}
}

Answer 1

Instead of printing response.toString(), you can read the actual body using response.readEntity(String.class). What you will find in the body is an error message from Jackson
No suitable constructor found for type [simple type, class simple.SimpleTest$Customer]: can not instantiate from JSON object (need to add/enable type information?)
At first glance your Customer class looks ok; it has a default constructor. But the really problem is that Jackson cannot instantiate it because it is a non-static inner class. So to fix it, simply make the Customer class static.
public static class Customer {}
As a general rule, when working with JSON and Jackson with Jersey, often when you get a 400, it a a problem with Jackson, and Jackson is pretty good at spitting out a meaningful message that will help us debug.