Map to Map from restTemplate

Question

I do restTemplate call and receive rawMap. From debug I see that key class and value class are String. Its ok because service that response to my restTemplate sends map in JSON. Now I want to crate Map with this code:

Map<String, Integer> gameIdsMap = new HashMap<>();
rawGameIdsMap.forEach(((key, value) -> gameIdsMap.put(String.valueOf(key), Integer.parseInt(String.valueOf(value)))));

Im curious. Is there more efficient and more clear way to do it? I cant just receive from restTemplate Map <String,Integer>.

RestTemplate

Map rawGameIdsMap = Objects.requireNonNull(restTemplate.getForObject(uriFactory.getReverseGameIdsURI(), Map.class));

I'm note sure, but somthing like that may work `Map casted = raw.parallelStream().map(Map::put);` — Zorglube, Aug 19 '19 at 14:01
https://stackoverflow.com/questions/8108887/generics-with-spring-resttemplate — chrylis -cautiouslyoptimistic-, Aug 19 '19 at 14:02

davidxxx · Accepted Answer · 2019-08-19T15:08:29.570

2

The RestTemplate class provides several exchange() methods.
It allows to specify as parameter an instance of ParameterizedTypeReference which the aim is to capture and pass a generic type. So you could do something like :

Map<String, String> gameIdsMap = Objects.requireNonNull(
    template.exchange(uri, HttpMethod.GET, null, new ParameterizedTypeReference<Map<String, String>>() {
    }).getBody());

Doing it :

Map<String, Integer> gameIdsMap= Objects.requireNonNull(
    template.exchange(uri, HttpMethod.GET, null, new ParameterizedTypeReference<Map<String, Integer>>() {
    }).getBody());

is aslo correct (at least with Jackson) but if the value cannot be converted to an Integer. In this case, it will provoke a deserialiaztion exception at runtime.

edited Aug 19 '19 at 15:08

answered Aug 19 '19 at 14:10

davidxxx

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@Sotirios Delimanolis Do you have a Jackson/Gson reference or a concrete example that shows that such a thing? Sorry, not time to write a real test now. – davidxxx Aug 19 '19 at 14:40
I have a doubt for the last one with `exchange()` of Spring template. I will give it a go. – davidxxx Aug 19 '19 at 14:47
1

@Sotirios Delimanolis I checked that. It works as you said. At least with Jackson. I would delete my answer but cannot since it is accepted. I updated for at least to be conform to the reality. – davidxxx Aug 19 '19 at 15:09

Map to Map from restTemplate

1 Answers1