How to use #HEAD in jax-rs using Jersey API or any other jax-rs API? - rest

Question

How to use #HEAD in jax-rs using Jersey API or any other jax-rs API ? please give me sample.

Answer 1

You don't need to explicitly support HEAD as Jersey will automatically support it. Here is what Jersey's the documentation says:
By default the JAX-RS runtime will automatically support the methods HEAD and OPTIONS, if not explicitly implemented. For HEAD the runtime will invoke the implemented GET method (if present) and ignore the response entity (if set). For OPTIONS the Allow response header will be set to the set of HTTP methods support by the resource. In addition Jersey will return a WADL document describing the resource.
(Source: https://eclipse-ee4j.github.io/jersey.github.io/documentation/latest/user-guide.html#d0e2157)

Answer 2

Here is some dirt simple code illustrating how to send a HEAD request using the Jersey client:
ClientConfig config = new DefaultClientConfig();
Client client = Client.create(config);
WebResource resource = client
.resource("http://localhost:8080/services/echo?message=Hello+World");
ClientResponse response = resource.accept(
MediaType.APPLICATION_JSON).head();
System.out.println(response);
Note the use of the head method. The response object returned contains lots of useful information, like the content type produced, the status code of the request, etc etc. The example can be translated to other client library types, but basically you send exactly the same request as you would with a GET, but with the HEAD method instead. Heres an example of the request that would be sent via a browser tool like 'REST Console':
Request
HEAD /services/echo?message=Hello+World HTTP/1.1
Host: localhost:8080
Connection: keep-alive
Content-Length: 0
Accept: application/json
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.65 Safari/537.31
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
Cookie: JSESSIONID=vWu5N2H8Y+P9SuZKWxhpIdgP.undefined
Response:
HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Content-Type: application/json
Content-Length: 0
Date: Fri, 03 May 2013 05:42:20 GMT