spring-webflux : How to Extract user defined object from Mono or Flux from the response without blocking?

Question

getUserDetails Method returns Mono of Type JsonNode. But I Actually want to return a Mono<User.java> or Flux<User.java>. please help modifying getBulkUserInfo or getUserDetails to get the Mono<User.java> or Flux<User.java>

public Mono<JsonNode> getUser(BigInteger Id){
    return this.client.get()
            .uri("/URL/{Id}",Id)
            .retrieve()
            .bodyToMono(JsonNode.class);
}

public Flux getBulkUsers(List<BigInteger> Ids){
    return Flux.fromIterable(Ids).flatMap(this::getUser);
}

But The json response from the Url is something like

{
"resultholder": {
            "totalResults": "1",
            "profiles": {
                "profileholder": {
                    "user": {
                        "country": "IND",
                        "zipCode": "560048",
                        "name":"Test"
                    }
                }
            }            
        }
}

I tried different ways but nothing worked subscribe() and .doOnNext(resp -> resp.get("resultholder").get("profiles").get("profileholder").get("user"))

    .bodyToMono(JsonNode.class)
.doOnNext(resp ->{return
 JSONUtils.deserialize(resp.get("resultholder").get("profiles").get("profileholder").get("user"), User.class)})

Did you look at these ?? -> https://stackoverflow.com/questions/25024999/convert-jsonnode-into-object/25026832 and https://stackoverflow.com/questions/19711695/convert-jsonnode-into-pojo — Harry, Jan 18 '22 at 21:09
Yes. I have already tried it. We have to use blocking to convert it to User.java using mapper. can we return specific jsonnode without blocking? '.retrieve().bodyToMono(JsonNode.class)' -Like do something with the response of Mono and then return it. — Akhyansh Bohidar, Jan 18 '22 at 21:37

Harry · Accepted Answer · 2022-01-19T00:22:58.013

This is pretty straightforward and there is no need to block. Its just applying further mappings on the response. You can use the following code for your problem

 return webClient
            .get()
            .uri("profilesEndPoint/" + id)
            .retrieve()
            .bodyToMono(JsonNode.class)
            .map(jsonNode ->
                    jsonNode.path("resultholder").path("profiles").path("profileholder").path("user")
            ).map(
                    userjsonNode -> mapper.convertValue(userjsonNode, User.class)
            );

Where mapper is jackson ObjectMapper

private final ObjectMapper mapper = new ObjectMapper();

If you have any issues please refer to this code here :

spring-webflux : How to Extract user defined object from Mono or Flux from the response without blocking?

1 Answers1