Read response body in JAX-RS client from a post request

Question

Having some sort of proxy between a mobile app and a web-service, we are puzzled by the response when issuing a post request. We receive response with status 200: OK. But we can not find/extract the JSON response body.

    Client client = ClientBuilder.newClient();
    WebTarget webTarget = client.target(WEBSERVICE_BASE_LOCATION + "mobileDevices?operatorCode=KPNSCP");
    String jsonString = "{\"osVersion\":\"4.1\",\"apiLevel\":16,\"devicePlatform\":\"ANDROID\"}";
    Builder builder = webTarget.request();
    Response response = builder.post(Entity.json(jsonString));

We are using JAX-RS. Can someone please provide some hints to extract the JSON body (String) from the server response?

Solution 1

Try this:

String output = response.getEntity(String.class);

EDIT

Thanks to @Martin Spamer to mention that it will work for Jersey 1.x jars only. For Jersey 2.x use

String output = response.readEntity(String.class);

Solution 2

I just found a solution for jaxrs-ri-2.16 - simply use

String output = response.readEntity(String.class)

this delivers the content as expected.

Solution 3

For my use case, none of the previous answers worked because I was writing a server-side unit test which was failing due the following error message as described in the Unable to Mock Glassfish Jersey Client Response Object question:

java.lang.IllegalStateException: Method not supported on an outbound message.
at org.glassfish.jersey.message.internal.OutboundJaxrsResponse.readEntity(OutboundJaxrsResponse.java:145)
at ...

This exception occurred on the following line of code:

String actJsonBody = actResponse.readEntity(String.class);

The fix was to turn the problem line of code into:

String actJsonBody = (String) actResponse.getEntity();

Solution 4

I also had the same issue, trying to run a unit test calling code that uses readEntity. Can't use getEntity in production code because that just returns a ByteInputStream and not the content of the body and there is no way I am adding production code that is hit only in unit tests.

My solution was to create a response and then use a Mockito spy to mock out the readEntity method:

Response error = Response.serverError().build();
Response mockResponse = spy(error);
doReturn("{jsonbody}").when(mockResponse).readEntity(String.class);

Note that you can't use the when(mockResponse.readEntity(String.class) option because that throws the same IllegalStateException.

Hope this helps!

View more solutions

Comments

[Martin Spamer]

This will only work with Jax 1.x, from Jersey: 2.x onward which the OP is using (We can tell from his use of ClientBuilder.newClient();). The response is response.readEntity(String.class);

[col.panic]

This does not work for jaxrs-ri-2.16, here you get org.glassfish.jersey.client.HttpUrlConnector$2@1255b1d1 as output.

[Alfishe]

Jersey developers drive me crazy. Every version methods naming and/or the whole workflow changes drastically. It's like playing Miner game. Find all mines from scratch.

[Whimusical]

Don't you like Agility? :)

[spectre007]

thanks, I got stuck into this for long time as I was using getEntity() to read response message body. getEntity() works only with Jersey 1.x and Jersey 2.0 has support for response.readEntity() to get response message body.

[Ben]

getEntity won't automatically read any backing InputStream, so be careful.

[Hristo Vrigazov]

@Whimusical I think he likes backward compatibility :)

[John Calcote]

Thank you! You're probably the first person to actually understand the OP's question. For all you other first-responders out there: no one cares how smart you are. They want to fix their problem. They're not interested in why jersey doesn't let you call readResponse in a unit test.

[dvlcube]

Note that if you get a com.owlike.genson.stream.JsonStreamException: Readen value can not be converted to String, you'll need to read the response stream manually to get the JSON String. That happened for me with Jersey 1.19.