How to add header in Rest aussured pf RestTemplate - automated-tests

Question

I have been trying to automate some API Testing using either resttemplate or Restassured library but im facing issues on post request. I cant seems to figure how to handle this. I keep getting 415 unsupported type error , I tried many ideas already and read hundreds of threads. Please if someone have a solution let me know.
This is the developer code
#POST
#Consumes(MediaType.MULTIPART_FORM_DATA)
#Produces(MediaType.APPLICATION_JSON)
public Response postData(#FormDataParam("file") InputStream is,
#FormDataParam("file") FormDataContentDisposition fileName,
#FormDataParam("checkInCommInfoInput") String checkInCommInfoInput,
#HeaderParam("authorization") String authString) { }
This is what I tried with resttemplate
String addURI = "https://myURI";
HttpHeaders headers = new HttpHeaders();
//headers.add("Accept","*/*");
headers.setContentType(MediaType.APPLICATION_JSON);
headers.add("Authorization", " a values will be here ");
System.out.println("**************************"+headers.getContentType());
String jsonBody = "my json file will be here";
//System.out.println("\n\n" + jsonBody);
HttpEntity<String> entity = new HttpEntity<String>(jsonBody, headers);
//POST Method to Add New Employee
response = this.restTemplate.postForEntity(addURI, entity, String.class);
responseBodyPOST = response.getBody();
// Write response to file
responseBody = response.getBody().toString();
What I tried with RestAssured
RestAssured.useRelaxedHTTPSValidation();
RestAssured.baseURI ="https://myURI";
EncoderConfig encoderconfig = new EncoderConfig();
Response response = RestAssured.given()
.header("Content-Type","application/json" )
.header("Authorization", "a vvalues will be here")
.header("Accept",ContentType.JSON )
.config(RestAssured.config()
.encoderConfig(encoderconfig.appendDefaultContentCharsetToContentTypeIfUndefined(false)))
//.contentType(ContentType.JSON)
// .accept("application/json")
.log().all().body(jsonBody).post()
.then()
.assertThat()
.log().ifError()
.statusCode(200)
.extract().response();
System.out.println("-------------"+ response.getBody().asString());

Answer 1

API under test #Consumes(MediaType.MULTIPART_FORM_DATA) but the test sends content with .header("Content-Type","application/json" )
415 error as you have clearly mentioned unsupported type error there is a content type mismatch between what the body content that the test client sends and what the API accepts.
See this blogpost: https://blog.jayway.com/2011/09/15/multipart-form-data-file-uploading-made-simple-with-rest-assured/ on how to do send MULTIPART_FORM_DATA