rest - How to set an "Accept:" header on Spring RestTemplate request?

Question

I want to set the value of the Accept: in a request I am making using Spring's RestTemplate.

Here is my Spring request handling code

@RequestMapping(
    value= "/uom_matrix_save_or_edit", 
    method = RequestMethod.POST,
    produces="application/json"
)
public @ResponseBody ModelMap uomMatrixSaveOrEdit(
    ModelMap model,
    @RequestParam("parentId") String parentId
){
    model.addAttribute("attributeValues",parentId);
    return model;
}

and here is my Java REST client:

public void post(){
    MultiValueMap<String, String> params = new LinkedMultiValueMap<String, String>();
    params.add("parentId", "parentId");
    String result = rest.postForObject( url, params, String.class) ;
    System.out.println(result);
}

This works for me; I get a JSON string from the server side.

My question is: how can I specify the Accept: header (e.g. application/json,application/xml, ... ) and request method (e.g. GET,POST, ... ) when I use RestTemplate?

Answer 1

I suggest using one of the exchange methods that accepts an HttpEntity for which you can also set the HttpHeaders. (You can also specify the HTTP method you want to use.)

For example,

RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.setAccept(Collections.singletonList(MediaType.APPLICATION_JSON));

HttpEntity<String> entity = new HttpEntity<>("body", headers);

restTemplate.exchange(url, HttpMethod.POST, entity, String.class);

I prefer this solution because it's strongly typed, ie. exchange expects an HttpEntity.

However, you can also pass that HttpEntity as a request argument to postForObject.

HttpEntity<String> entity = new HttpEntity<>("body", headers);
restTemplate.postForObject(url, entity, String.class); 

This is mentioned in the RestTemplate#postForObject Javadoc.

The request parameter can be a HttpEntity in order to add additional HTTP headers to the request.