Spring get MediaType of received body - spring

Question

Following this answer I've set my method in controller this way:
#PostMapping(path = PathConstants.START_ACTION, consumes = {MediaType.APPLICATION_FORM_URLENCODED_VALUE, MediaType.APPLICATION_JSON_VALUE})
public ResponseEntity<BaseResponse<ProcessInstance>> start(#PathVariable String processDefinitionId,
#RequestBody(required = false) String params)
Now I need to behave differently according to my #RequestBody being of one MediaType or the other, so I need to know whether my params body is json o urlencoded. Is there a way to do this?

Answer 1

You can simply inject Content-Type header.
#PostMapping(path = "/{processDefinitionId}", consumes = {MediaType.APPLICATION_FORM_URLENCODED_VALUE, MediaType.APPLICATION_JSON_VALUE})
public ResponseEntity<String> start(#PathVariable String processDefinitionId,
#RequestBody(required = false) String params,
#RequestHeader("Content-Type") String contentType) {
if (contentType.startsWith(MediaType.APPLICATION_JSON_VALUE)) {
System.out.println("json");
} else {
// ...
}
return ResponseEntity.ok(params);
}
But I would suggest to split this method on two methods with different consumes values:
#PostMapping(path = "/v2/{processDefinitionId}", consumes = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<String> startV2Json(#PathVariable String processDefinitionId,
#RequestBody(required = false) String params) {
return ResponseEntity.ok(params);
}
#PostMapping(path = "/v2/{processDefinitionId}", consumes = MediaType.APPLICATION_FORM_URLENCODED_VALUE)
public ResponseEntity<String> startV2UrlEncoded(#PathVariable String processDefinitionId,
#RequestBody(required = false) String params) {
return ResponseEntity.ok(params);
}