POST request via RestTemplate in JSON

Question

I didn't find any example how to solve my problem, so I want to ask you for help. I can't simply send POST request using RestTemplate object in JSON

Every time I get:

org.springframework.web.client.HttpClientErrorException: 415 Unsupported Media Type

I use RestTemplate in this way:

...
restTemplate = new RestTemplate();
List<HttpMessageConverter<?>> list = new ArrayList<HttpMessageConverter<?>>();
list.add(new MappingJacksonHttpMessageConverter());
restTemplate.setMessageConverters(list);
...
Payment payment= new Payment("Aa4bhs");
Payment res = restTemplate.postForObject("http://localhost:8080/aurest/rest/payment", payment, Payment.class);

What is my fault?

Doble

@troyfolger the url is no longer valid – Devout

Thanks - this link is working as of this writing: spring.io/guides/gs/consuming-rest – Diley

To address the specific OP issue, above, you are probably missing an HTTP header with appropriate content type, see the answer from morganw09dev below. – Diley

These issues are mostly related to the Server API configuration. You test the Server API using a Standalone client (like Postman ) and replicate the same headers in your request. At least in my case that did the Trick. – Orel

@Johnny B, if this has been answered please mark the answer – Spillway

Answer 1

This technique worked for me:

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
            
HttpEntity<String> entity = new HttpEntity<String>(requestJson, headers);
ResponseEntity<String> response = restTemplate.put(url, entity);

Rattoon

please explain which row should return result of http request – Parham

For me it was not necessary to specify any headers. I have used the HttpEntity that takes a single parameter. – Manzanilla

method .put() is void! – Teat

Using postForEntity(url, entity, String.class) works in place of put(url, entity) – Kinesthesia

In my case, put method throws Exception in thread "main" org.springframework.web.client.HttpClientErrorException: 405 HTTP method PUT is not supported by this URL – Azote

@Kanu, requestJson is valid JSON String or something else? – Pious

Make sure you use org.springframework.http.HttpHeaders and not java.net.http.HttpHeaders – Toastmaster

Answer 2

I ran across this problem when attempting to debug a REST endpoint. Here is a basic example using Spring's RestTemplate class to make a POST request that I used. It took me quite a bit of a long time to piece together code from different places to get a working version.

RestTemplate restTemplate = new RestTemplate();

String url = "endpoint url";
String requestJson = "{\"queriedQuestion\":\"Is there pain in your hand?\"}";
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);

HttpEntity<String> entity = new HttpEntity<String>(requestJson,headers);
String answer = restTemplate.postForObject(url, entity, String.class);
System.out.println(answer);

The particular JSON parser my rest endpoint was using needed double quotes around field names so that's why I've escaped the double quotes in my requestJson String.

Nothing

can u please help me on this #42241427 – Katheykathi

Can Spring use the message converters to automatically convert the Java Object to json like it did in Restful API with RestTemplate? – Elman

Setting media type to APPLICATION_JSON is the key to resolve the problem. – Appendicular

I resolved my problem using HttpEntity<String> entity = new HttpEntity<String>(requestJson,headers); this line – Skelton

Answer 3

I've been using rest template with JSONObjects as follow:

// create request body
JSONObject request = new JSONObject();
request.put("username", name);
request.put("password", password);

// set headers
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<String> entity = new HttpEntity<String>(request.toString(), headers);

// send request and parse result
ResponseEntity<String> loginResponse = restTemplate
  .exchange(urlString, HttpMethod.POST, entity, String.class);
if (loginResponse.getStatusCode() == HttpStatus.OK) {
  JSONObject userJson = new JSONObject(loginResponse.getBody());
} else if (loginResponse.getStatusCode() == HttpStatus.UNAUTHORIZED) {
  // nono... bad credentials
}

Strongbox

Thanks - the JSONObject toString method was useful for me, it helped me get my JSONString accurate. – Cart

How to developed above code for this : curl -vvv -X POST "localhost:8080/SillyService_SRC/oauth/…" ? – Schizothymia

@Mikael Lepistö How can i retrieve these parameters from json at server end?? – Lodestone

@Lodestone I don't understand what do you mean... this is server side code in the response. If you are thinking how to parse json response, it depends on framework that you are using. – Declarer

@MikaelLepistö I mean how to parse json response in the other end including how to receive the response in java??You have posted only the code for one end(ie, server side). – Lodestone

@Lodestone If you get request body containing JSON string from your choice of HTTP server you can convert it to JSONObject like this: JSONObject obj = new JSONObject(jsonString);, but pretty much every java web server framework has some better way to do it. – Declarer

Can we let Spring convert the java object to json for us with message converters behind the screen like Rest APIs? – Elman

@Elman I don't suppose Spring does that automatically, probably you need to configure some service for sending requests and write DTOs and use them if you want more automation. Maybe someone who know Spring better than me can have better answer... – Declarer

Answer 4

As specified here I guess you need to add a messageConverter for MappingJacksonHttpMessageConverter

Voyageur

Answer 5

I'm doing in this way and it works .

HttpHeaders headers = createHttpHeaders(map);
public HttpHeaders createHttpHeaders(Map<String, String> map)
{   
    HttpHeaders headers = new HttpHeaders();
    headers.setContentType(MediaType.APPLICATION_JSON);
    for (Entry<String, String> entry : map.entrySet()) {
        headers.add(entry.getKey(),entry.getValue());
    }
    return headers;
}

// Pass headers here

 String requestJson = "{ // Construct your JSON here }";
logger.info("Request JSON ="+requestJson);
HttpEntity<String> entity = new HttpEntity<String>(requestJson, headers);
ResponseEntity<String> response = restTemplate.exchange(url, HttpMethod.POST, entity, String.class);
logger.info("Result - status ("+ response.getStatusCode() + ") has body: " + response.hasBody());
logger.info("Response ="+response.getBody());

Hope this helps

Preemption

Answer 6

If you are using Spring 3.0, an easy way to avoid the org.springframework.web.client.HttpClientErrorException: 415 Unsupported Media Type exception, is to include the jackson jar files in your classpath, and use mvc:annotation-driven config element. As specified here.

I was pulling my hair out trying to figure out why the mvc-ajax app worked without any special config for the MappingJacksonHttpMessageConverter. If you read the article I linked above closely:

Underneath the covers, Spring MVC delegates to a HttpMessageConverter to perform the serialization. In this case, Spring MVC invokes a MappingJacksonHttpMessageConverter built on the Jackson JSON processor. This implementation is enabled automatically when you use the mvc:annotation-driven configuration element with Jackson present in your classpath.

Knotting

Answer 7

The "415 Unsupported Media Type" error is telling you that the server will not accept your POST request. Your request is absolutely fine, it's the server that's mis-configured.

MappingJacksonHttpMessageConverter will automatically set the request content-type header to application/json, and my guess is that your server is rejecting that. You haven't told us anything about your server setup, though, so I can't really advise you on that.

Lenlena

Answer 8

Why work harder than you have to? postForEntity accepts a simple Map object as input. The following works fine for me while writing tests for a given REST endpoint in Spring. I believe it's the simplest possible way of making a JSON POST request in Spring:

@Test
public void shouldLoginSuccessfully() {
  // 'restTemplate' below has been @Autowired prior to this
  Map map = new HashMap<String, String>();
  map.put("username", "bob123");
  map.put("password", "myP@ssw0rd");
  ResponseEntity<Void> resp = restTemplate.postForEntity(
      "http://localhost:8000/login",
      map,
      Void.class);
  assertThat(resp.getStatusCode()).isEqualTo(HttpStatus.OK);
}

Feune

This is really far down, but it worked for me. Not sure if there are any drawbacks, but it seems to be by far the simplest approach. – Aryanize

Answer 9

This code is working for me;

RestTemplate restTemplate = new RestTemplate();
Payment payment = new Payment("Aa4bhs");
MultiValueMap<String, Object> map = new LinkedMultiValueMap<String, Object>();
map.add("payment", payment);
HttpEntity<MultiValueMap<String, Object>> httpEntity = new HttpEntity<MultiValueMap<String, Object>>(map, headerObject);

Payment res = restTemplate.postForObject(url, httpEntity, Payment.class);

Horseshoe

i am using a very similar approach and it did NOT work for me. for some reason my equivalent of your 'map' is not being converted to json or included as outbound body i.e., the target service does NOT see any payload. – Stuyvesant

yep, this solution as shown will post in application/x-www-form-urlencoded format. – Aret

I could not use a JSON string for payload my parser would not allow it (Jackson). I had to use a Java Map type object like above to solve my problem. – Amery

Answer 10

I was getting this problem and I'm using Spring's RestTemplate on the client and Spring Web on the server. Both APIs have very poor error reporting, making them extremely difficult to develop with.

After many hours of trying all sorts of experiments I figured out that the issue was being caused by passing in a null reference for the POST body instead of the expected List. I presume that RestTemplate cannot determine the content-type from a null object, but doesn't complain about it. After adding the correct headers, I started getting a different server-side exception in Spring before entering my service method.

The fix was to pass in an empty List from the client instead of null. No headers are required since the default content-type is used for non-null objects.

Coulter

Answer 11

If you dont want to process response

private RestTemplate restTemplate = new RestTemplate();
restTemplate.postForObject(serviceURL, request, Void.class);

If you need response to process

String result = restTemplate.postForObject(url, entity, String.class);

Singleaction

Answer 12

I tried as following in spring boot:

ParameterizedTypeReference<Map<String, Object>> typeRef = new ParameterizedTypeReference<Map<String, Object>>() {};
public Map<String, Object> processResponse(String urlendpoint)
{
    try{
    
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        //reqobj
        JSONObject request = new JSONObject();
        request.put("username", name);
        //Or Hashmap 
        Map<String, Object> reqbody =  new HashMap<>();
        reqbody.put("username",username);
        Gson gson = new Gson();//mvn plugin to convert map to String
        HttpEntity<String> entity = new HttpEntity<>( gson.toJson(reqbody), headers);
        ResponseEntity<Map<String, Object>> response = resttemplate.exchange(urlendpoint, HttpMethod.POST, entity, typeRef);//example of post req with json as request payload
        if(Integer.parseInt(response.getStatusCode().toString()) == HttpURLConnection.HTTP_OK)
        {
            Map<String, Object>  responsedetails = response.getBody();
            System.out.println(responsedetails);//whole json response as map object
            return responsedetails;
        }
    } catch (Exception e) {
        // TODO: handle exception
        System.err.println(e);
    }
    return null;
}

Smyth

Answer 13

If you don't want to map the JSON by yourself, you can do it as follows:

RestTemplate restTemplate = new RestTemplate();
restTemplate.setMessageConverters(Arrays.asList(new MappingJackson2HttpMessageConverter()));
ResponseEntity<String> result = restTemplate.postForEntity(uri, yourObject, String.class);

Cryptic

Answer 14

For me error occurred with this setup:

AndroidAnnotations Spring Android RestTemplate Module and ...

GsonHttpMessageConverter

Android annotations has some problems with this converted to generate POST request without parameter. Simply parameter new Object() solved it for me.

Conchiferous

Answer 15

You can make request as a JSON object

JSONObject request = new JSONObject();
request.put("name","abc"); 
ResponseEntity<JSONObject> response =restTemplate.postForEntity(append_url,request,JSONObject.class);                                                          `enter code here`

Prolusion