RestTemplate restTemplate = new RestTemplate();

        HttpHeaders headers = new HttpHeaders();

        MediaType type = MediaType.parseMediaType("application/json; charset=UTF-8");

        headers.setContentType(type);

        headers.add("Accept", MediaType.APPLICATION_JSON.toString());

        String jsonStr = JSONObject.toJSONString(params);

        HttpEntity formEntity = new HttpEntity( jsonStr ,headers);

        String result = restTemplate.getForObject(url, String.class);