我有以下webclient调用

public Mono<String> sendFile(final MultipartFile multipartFile) {
    Mono<Response> response = webClient.post()
                .uri(new URI("someurl"))
                .body(BodyInserters.fromMultipartData(multiValueMap))
                .retrieve()
                .bodyToMono(Response.class);

    // Need to implement additional logic here to convert the Mono<Response> into Mono<RequestID>

}

public class Response {

    private RequestID requestID;

}

public class RequestID {

    private String requestID;

}

对API的调用返回到JSON Response POJO对象中，但是我只对RequestID POJO中的requestID感兴趣，所以我想将我的Mono转换< Response >为Mono< RequestId >，但不知道如何做到这一点？
所以对于我的控制器，我基本上想要类似于这样的东西：

@PostMapping("/request")
    public Mono<ResponseEntity> sendRequest(@RequestPart(value = "file") final MultipartFile multipartFile) {
        Mono<RequestID> request =  service.sendFile(multipartFile);
        Response2<String> response = new Response<>(request.getRequestID, true, "SUCCESS"); // Response2 is just a POJO with three fields
        return new Mono<ResponseEntity<>>(response, HttpStatus.CREATED);
    }