How to use HttpEntity and PostForObject in resttemplate

I'm trying to store an employee object into mongodb using the Spring restful webservices and resttemplate's postForObject.

Here I have used HttpEntity and postForObject to post the employee object to restful webservice.

In the restful webservice,I'm trying to retrieve the employee Object fields through @FormParam annotation.

I'm able to insert a record into mongodb but the fields are stored as null like this: { "_id" : ObjectId("552e133ee4b0b6b3d3154262"), "client_ip" : null, "start_time" : null, "end_time" : null }

 My client code:
 ================  
    RestTemplate restTemplate = new RestTemplate();
           Employee emp = new Employee();
            emp.setClientIp("188.96.258.136");
            emp.setStartTime("1345678786789");
            emp.setEndTime("1341859801516");

            List<HttpMessageConverter<?>> messageConverters = new ArrayList<HttpMessageConverter<?>>();
            messageConverters.add(new FormHttpMessageConverter());
            messageConverters.add(new StringHttpMessageConverter());
            messageConverters.add(new MappingJackson2HttpMessageConverter());
            restTemplate.setMessageConverters(messageConverters);

             HttpHeaders headers = new HttpHeaders();
             headers.setContentType(MediaType.APPLICATION_JSON);
             HttpEntity<Employee> entity = new HttpEntity<Employee>(emp, headers);


            Employee result2 = restTemplate.postForObject("http://localhost:8080/restful/insert/post", entity, Employee.class);

    My RestfulWebservice code:
    ===========================

        @POST
        @Path("/post")
        @Produces(MediaType.APPLICATION_JSON)
        @Consumes({MediaType.APPLICATION_JSON,MediaType.TEXT_PLAIN})
        public Response postData(@FormParam("client_ip") String client_ip,
                @FormParam("start_time") String start_time, @FormParam("end_time") String end_time)
                throws UnknownHostException, MongoException {
            String json = null;
                Mongo mongo = new Mongo("192.168.7.102", 27017);
                DB db = mongo.getDB("sample");

                DBCollection col = db.getCollection("data");
             DBObject dbo = new BasicDBObject();
             dbo.put("client_ip",client_ip );
             dbo.put("start_time",start_time );
             dbo.put("end_time",end_time );
             col.insert(dbo);

                    json = JSON.serialize(dbo);


            return Response.status(200).entity(json).build();
        }

Can anyone suggest me how to post an employee object into mongodb using the resttemplate and how to retrieve the fields at the restful webservice end.

Thank in advance