In our project, we call an external API with postForEntity and receive the following: error:org.springframework.web.server.ResponseStatusException: 415 UNSUPPORTED_MEDIA_TYPE "Could not determine reason or message. Plain body: ""
final ActionDto actionDto = new ActionDto ().setRequestId(requestId);
final ResponseEntity<ActionResponseDto> response = restTemplate.postForEntity(url, actionDto, ActionResponseDto.class);
I managed to fix this error by using exchange instead of postForEntity and adding a media type:
final HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
val entity = new HttpEntity(actionDto , headers);
final ResponseEntity<ActionResponseDto> response =
restTemplate.exchange(
url,
HttpMethod.POST,
entity,
ActionResponseDto.class);
My question is the following, could you give me some hints why before with postForEntity it worked and now suddenly it doesn't?
I also checked the external API and the method looks like bellow, and nothing has changed:
#PostMapping("/action/start")
#ResponseStatus(HttpStatus.OK)
#Operation(summary = "Start the action")
public ResponseEntity<ActionResponseDto> startAction(#RequestBody final ActionDto requestDto) {
.....
}
Could it be due to some dependencies? This error is very strange...
Thank you! :)
I need to be able to access the status code of a request. The call can be successful in either of two ways 200 or 201. This is obvious when calling via postman but using the web client, so far I haven't been able to determine which has occurred.
webClient.post()
.uri(url)
.header(HttpHeaders.ACCEPT, MediaType.ALL_VALUE)
.header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
.header(HttpHeaders.AUTHORIZATION, bearerToken)
.bodyValue(bodyMap)
.retrieve()
.onStatus(
HttpStatus.BAD_REQUEST::equals,
response -> response.bodyToMono(String.class).map(Exception::new))
.bodyToMono(Map.class)
I was thinking maybe I could set an integer variable using within the onStatus() lambda function. Is it even possible to access external variables within a lambda function?
int responseStatus;
// post call
.onStatus(
HttpStatus.CREATED::equals,
response -> ... // do something to set responseStatus
You could use .toEntity(Class<T> bodyClass) method to get entity wrapped in response object ResponseEntity<T>
var response = webClient.post()
.uri(uri)
.retrieve()
.toEntity(Map.class)
.map(res -> {
if (res.getStatusCode().equals(HttpStatus.OK)) {
...
}
return res.getBody();
});
I'm able to return ResponseEntity using toEntity() method like below:
#GetMapping("/uri")
public Mono<ResponseEntity<Data[]>> methodName() {
return webClient
.get()
.uri("http://localhost:8088/externalService")
.accept(MediaType.APPLICATION_JSON)
.retrieve()
.toEntity(Data[].class);
}
But I want to process response headers before returning.
The above code converts WebClient response to ResponseEntity and returns immediately but I want to store it in a ResponseEntity variable, process it, and then return the ResponseEntity back.
I referred this -> Spring WebClient Documentation
WHen I tried to store it in a varibale, I get this error -> "block()/blockFirst()/blockLast() are blocking, which is not supported in thread reactor-http-nio-3"
You can simply use the Reactor's map operator to modify the headers:
return webClient
.get()
.uri("http://localhost:8088/externalService")
.accept(MediaType.APPLICATION_JSON)
.retrieve()
.toEntity(Data[].class)
.map(responseEntity -> responseEntity.getHeaders().add("header", "header-value");
Alternatively, you can use .handle operator in order to provide response processing:
.handle((responseEntity, sink) -> {
if(!isValid(responseEntity)){
sink.error(new InvalidResponseException());
} else if (isOk(responseEntity))
sink.next(responseEntity);
}
else {
//just ignore element
}
})
Spring Starter Web dependency was missing in my pom.xml. Found it and added it back.
Now able to get WebClient response in ResponseEntity format.
I am using RestTemplate to make an HTTP call to our service which returns a simple JSON response. I don't need to parse that JSON at all. I just need to return whatever I am getting back from that service.
So I am mapping that to String.class and returning the actual JSON response as a string.
RestTemplate restTemplate = new RestTemplate();
String response = restTemplate.getForObject(url, String.class);
return response;
Now the question is -
I am trying to extract HTTP Status codes after hitting the URL. How can I extract HTTP Status code from the above code? Do I need to make any change into that in the way I doing it currently?
Update:-
This is what I have tried and I am able to get the response back and status code as well. But do I always need to set HttpHeaders and Entity object like below I am doing it?
RestTemplate restTemplate = new RestTemplate();
//and do I need this JSON media type for my use case?
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
//set my entity
HttpEntity<Object> entity = new HttpEntity<Object>(headers);
ResponseEntity<String> out = restTemplate.exchange(url, HttpMethod.GET, entity, String.class);
System.out.println(out.getBody());
System.out.println(out.getStatusCode());
Couple of question - Do I need to have MediaType.APPLICATION_JSON as I am just making a call to url which returns a response back, it can return either JSON or XML or simple string.
Use the RestTemplate#exchange(..) methods that return a ResponseEntity. This gives you access to the status line and headers (and the body obviously).
getStatusCode()
getHeaders()
If you don´t want to leave the nice abstraction around RestTemplate.get/postForObject... methods behind like me and dislike to fiddle around with the boilerplate stuff needed when using RestTemplate.exchange... (Request- and ResponseEntity, HttpHeaders, etc), there´s another option to gain access to the HttpStatus codes.
Just surround the usual RestTemplate.get/postForObject... with a try/catch for org.springframework.web.client.HttpClientErrorException and org.springframework.web.client.HttpServerErrorException, like in this example:
try {
return restTemplate.postForObject("http://your.url.here", "YourRequestObjectForPostBodyHere", YourResponse.class);
} catch (HttpClientErrorException | HttpServerErrorException httpClientOrServerExc) {
if(HttpStatus.NOT_FOUND.equals(httpClientOrServerExc.getStatusCode())) {
// your handling of "NOT FOUND" here
// e.g. throw new RuntimeException("Your Error Message here", httpClientOrServerExc);
}
else {
// your handling of other errors here
}
The org.springframework.web.client.HttpServerErrorException is added here for the errors with a 50x.
Now you´re able to simple react to all the StatusCodes you want - except the appropriate one, that matches your HTTP method - like GET and 200, which won´t be handled as exception, as it is the matching one. But this should be straight forward, if you´re implementing/consuming RESTful services :)
If you want all the HTTPStatus from a RestTemplate including 4XX and 5XX, you will have to provide an ResponseErrorHandler to the restTemplate, since the default handler will throw an exception in case of 4XX or 5XX
We could do something like that :
RestTemplate restTemplate = new RestTemplate();
restTemplate.setErrorHandler(new DefaultResponseErrorHandler() {
#Override
public boolean hasError(HttpStatus statusCode) {
return false;
}
});
ResponseEntity<YourResponse> responseEntity =
restTemplate.getForEntity("http://your.url.here", YourResponse.class);
assertThat(responseEntity.getStatusCode()).isEqualTo(HttpStatus.XXXX);
private RestTemplate restTemplate = new RestTemplate();
ResponseEntity<String> response = restTemplate.exchange(url,HttpMethod.GET, requestEntity,String.class);
response contains 'body', 'headers' and 'statusCode'
to get statusCode : response.getStatusCode();
exchange(...) works but if you want less code, you can use
org.springframework.boot.test.web.client.TestRestTemplate.getForEntity(...)
which returns an Entity containing StatusCode. Change your example code to this:
RestTemplate restTemplate = new RestTemplate();
ResponseEntity<String> response = restTemplate.getForEntity(url, String.class);
HttpStatus statusCode = response.getStatusCode();
To test it you can use this snippet from my unit test:
ResponseEntity<String> response = restTemplate.getForEntity(url, String.class);
assertResponseHeaderIsCorrect(response, HttpStatus.OK);
/**
* Test the basics of the response, non-null, status expected, etc...
*/
private void assertResponseHeaderIsCorrect(ResponseEntity<String> response, HttpStatus expectedStatus) {
assertThat(response).isNotNull();
assertThat(response.getHeaders().getContentType()).isEqualTo(MediaType.APPLICATION_JSON_UTF8);
assertThat(response.getStatusCode()).isEqualTo(expectedStatus);
}
There can be some slightly trickier use cases someone might fall in (as I did). Consider the following:
Supporting a Page object in order to use it with RestTemplate and ParameterizedTypeReference:
RestPageResponse:
import java.util.ArrayList;
import java.util.List;
import org.springframework.data.domain.PageImpl;
import org.springframework.data.domain.Pageable;
public class RestResponsePage<T> extends PageImpl<T>{
private static final long serialVersionUID = 3248189030448292002L;
public RestResponsePage(List<T> content, Pageable pageable, long total) {
super(content, pageable, total);
}
public RestResponsePage(List<T> content) {
super(content);
}
public RestResponsePage() {
super(new ArrayList<T>());
}
}
Using ParameterizedTypeReference will yield the following:
ParameterizedTypeReference<RestResponsePage<MyObject>> responseType =
new ParameterizedTypeReference<RestResponsePage<MyObject>>() {};
HttpEntity<RestResponsePage<MyObject>> response = restTemplate.exchange(oauthUrl, HttpMethod.GET, entity, responseType);
Calling #exchange:
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.MULTIPART_FORM_DATA);
HttpEntity<?> entity = new HttpEntity<>(headers);
response = restTemplate.exchange("localhost:8080/example", HttpMethod.GET, entity, responseType);
Now here is the "tricky" part.
Trying to call exchange's getStatusCode will be impossible because the compiler, unfortunately, will be unaware of the "intended" type of response.
That is because generics are implemented via type erasure which removes all information regarding generic types during compilation (read more - source)
((ResponseEntity<RestResponsePage<MyObject>>) response).getStatusCode()
In this case, you have to explicitly cast the variable to the desired Class to get the statusCode (and/or other attributes)!
Putting this much of code is enough for me
HttpStatus statusCode = ((ResponseEntity<Object>) responseOfEsoft).getStatusCode();
You can use this solution
RestTemplate restTemplate = new RestTemplate();
final String baseUrl = "http://www.myexampleurl.com";
URI uri = new URI(baseUrl);
ResponseEntity<String> result = restTemplate.getForEntity(uri, String.class);
//get status code
int statuCode = result.getStatusCodeValue();
Was able to solve this through:
HttpEntity<Object> entity = restTemplate.getForEntity(uri, Object.class);
ResponseEntity<String> result = restTemplate.exchange(uri, HttpMethod.GET, entity, String.class);
System.out.println(result.getStatusCode());
I am posting information to a web service using RestTemplate.postForObject. Besides the result string I need the information in the response header. Is there any way to get this?
RestTemplate template = new RestTemplate();
String result = template.postForObject(url, request, String.class);
Ok, I finally figured it out. The exchange method is exactly what i need. It returns an HttpEntity which contains the full headers.
RestTemplate template = new RestTemplate();
HttpEntity<String> response = template.exchange(url, HttpMethod.POST, request, String.class);
String resultString = response.getBody();
HttpHeaders headers = response.getHeaders();
Best thing to do whould be to use the execute method and pass in a ResponseExtractor which will have access to the headers.
private static class StringFromHeadersExtractor implements ResponseExtractor<String> {
public String extractData(ClientHttpResponse response) throws
{
return doSomthingWithHeader(response.getHeaders());
}
}
Another option (less clean) is to extend RestTemplate and override the call to doExecute and add any special header handling logic there.
HttpEntity<?> entity = new HttpEntity<>( postObject, headers ); // for request
HttpEntity<String> response = template.exchange(url, HttpMethod.POST, entity, String.class);
String result= response.getBody();
HttpHeaders headers = response.getHeaders();
I don't know if this is the recommended method, but it looks like you could extract information from the response headers if you configure the template to use a custom HttpMessageConverter.