how to convert LinkedHashMap to Custom java object?

Question

I\'m trying to get the data from one app to another via RESTful WS and it works, but I cannot use this data since I cannot cast it... WS returns a List of objects like this:

Answer 1

In my use case, I had 10 different APIs. All my API Responses were in the same json format but the content was different in one of the tags - /result/data

{
    "success": true,
    "result": {
        "type": "transactions",
        "data": {}
    },
    "error": [],
    "metadata": {
        "version": "v1",
        "code": 200,
        "desc": "OK",
        "trackingId": "TRACKINGID-1588097123800-1234567890",
        "generatedTimestamp": "2020-07-14T09:41:06.198Z"
    },
    "link": {
        "self": "/v1/myapp/customer/enquiry"
    }
}

In my spring boot code, I used the following generic method for all my API calls -

 ApiResponse execute(URI uri, T entity, Class clazz) {
    HttpEntity httpEntity = new HttpEntity<>(entity);
    ApiResponse body = this.restTemplate.exchange(uri, HttpMethod.POST, httpEntity,
            new ParameterizedTypeReference>() {
            }).getBody();
    return body;
}

It gave me the same error as you reported above. Based on this and some other SO answers, I tried the below as well and it did not work -

 ApiResponse execute(URI uri, T entity, Class clazz) {
    HttpEntity httpEntity = new HttpEntity<>(entity); 
    ResponseEntity response = this.scVaultCoreApi.exchange(uri, HttpMethod.POST, httpEntity, String.class);
    ObjectMapper mapper = new ObjectMapper();
    try {
        return mapper.readValue(response.getBody(), new TypeReference>() {
        });
    } catch (Exception e) {
        throw new RuntimeException();
    }
}

The other solution that worked was manually parsing the response stream using the ObjectMapper in jackson. But I couldn't do that for so many APIs I was using and the above error came in some APIs calls only. So, only for those APIs, instead of relying on the TypeReference conversion to the Class, I did not change the above methods that I defined, but I extracted the ApiResponse as ApiResponse