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Calling multiple external APIs in Spring Boot

I am working on a project but it requires me to call multiple external APIs. I basically have to call an API to get a player id by giving a name. Then use that player id to get a list of match ids. Then make calls for each match id to get details on each match. its alot and doesnt seem optimal but its the only way to do it. I was going to use rest template to make a call to the following
https://americas.api.riotgames.com/lol/match/v5/matches/by-puuid/HDzjdaStxhHcceGGd8qJcc4Vw45FOlOQ1PNXKQ0h9_iqfwHP3oI0spl1bLUOw_7_J49vzaIKylv5Vg/ids?start=0&count=20
I have to pass in headers as well such as
riot token : token
"Origin": "https://developer.riotgames.com"
I was wondering how I can do this in Java Spring boot. I saw RestTemplate would be used but I couldnt figure out how to include the headers. Any guidance would be appreciated.

You can call RestTemplate.exchange() using either the method signature with RequestEntity or with HttpEntity.
// Using RequestEntity
RequestEntity<?> request= RequestEntity.get(url).header(headerName, headerValue).build();
ResponseEntity<String> response = restTemplate.exchange(request, String.class);
// Using HttpEntity
HttpHeaders headers = new HttpHeaders();
headers.set(headerName, headerValue);
HttpEntity httpEntity = new HttpEntity(/* this is nullable */ requestBody, headers);
ResponseEntity,String> response = restTemplate.exchange(url, HttpMethod.GET, httpEntity, String.class);
Would also recommend reading through the following:
https://howtodoinjava.com/spring-boot2/resttemplate/spring-restful-client-resttemplate-example/
https://www.baeldung.com/rest-template
How to set an "Accept:" header on Spring RestTemplate request?

Spring boot rest template - HttpMessageConverter cannot convert objects

hello everyone I have a problem that I do not understand why this is happening. I am working with spring boot and deploying with Kubernetes. after a while, the restTemplate stops working and I do not know what can be the cause. this is how I am creating the restTemplate class
#Bean
public RestTemplate vanillaRestTemplate() {
RestTemplate restTemplate = new RestTemplate();
restTemplate.setErrorHandler(new RestTemplateErrorHandler());
restTemplate.setRequestFactory(new HttpComponentsClientHttpRequestFactory());
return restTemplate;
}
after a while some of my APIs that is using restTemplate returns an error like this:
{
"status": 500,
"body": "{ message: Could not extract response: no suitable HttpMessageConverter found for response type [interface java.util.List] and content type [application/json;charset=UTF-8] , cause: null }",
}
this is only an example. resttemplate will have a problem with many classes such as Map, String, etc when this happens. and this is how I am sending the request:
ResponseEntity<List> adsRes = restTemplate.getForEntity(url, List.class);
the weird part is when I restart the app on the server everything starts working again and the APIs have no problem at all. even the ones that returned an error.
I have read this question but, as you can see I have not set any interceptor or anything like that to resttemplate
thanks in advance

Try replace the way how you are calling to the endpoint by the following code
ResponseEntity<YourObject[]> response = restTemplate.getForEntity("urlService",
YourObject[].class);
YourObject[] yourObjects= response.getBody();
List<YourObject> list = Arrays.asList(yourObjects);

Rest call without RestTemplate

WebSphere don't load previous classes (com.fasterxml.jackson.core.JsonGenerator and com.fasterxml.jackson.databind.ObjectMapper) of RestTemplate for do a REST call with customize class to catch JSON in response.
Now I'm trying to find an alternative to RestTemplate for do REST call.
Anyone have an idea?
This is my actually code but don't load previous classes so don't match JSON
RestTemplate restTemplate = new RestTemplate();
ResponseEntity<Person> restResponse = restTemplate.getForEntity(providerUrl, Person.class);

Did you consider the following:
ResponseEntity<String> restResponse = restTemplate.getForEntity(providerUrl, String.class);
Then parse the response body yourself?

How to get the HTTP status of an API in spring boot when we hit it internally using Rest template

I want to get the object as well as the HTTP response of one api into another in Spring code. For that I am using a rest template and I am getting the desired Object from it successfully.
But I want to fetch HTTP response also for the respective api.
What should I do to get this?
RestTemplate restTemplate = new RestTemplate();
Quote quote = restTemplate.getForObject("http://gturnquist-quoters.cfapps.io/api/random", Quote.class);
System.out.println("quote "+quote);
System.out.println(quote.getType());
log.info(quote.toString());

getForObject method of RestTemplate only gets the result. If you're interest in the status code you should invode exchange which returns a ResponseEntity which has a getStatusCode method.
RestTemplate restTemplate = new RestTemplate();
ResponseEntity<Quote> response= restTemplate.exchange ("http://gturnquist-quoters.cfapps.io/api/random", HttpMethod.GET, null, Quote.class);
Quote quote = response..getBody();
System.out.println("status "+response..getStatusCode());
System.out.println("quote "+quote);
System.out.println(quote.getType());

Handle multipart/mixed response with Spring RestTemplate

I'm making a rest call to an endpoint that returns a multipart/mixed payload.
Here's the call using Spring's RestTemplate:
ResponseEntity<String> res = template.exchange(queryStr, HttpMethod.GET, entity, String.class);
I know I can get the entire body from the ResponseEntity as a String, but I don't want to have to manually parse it. Isn't there a more elegant way to handle the parsing of multipart/mixed. I've tried things like:
ResponseEntity<MultipartFile> res = template.exchange(queryStr, HttpMethod.GET, entity, MultipartFile.class);
but I get this exception:
org.springframework.web.client.RestClientException Could not extract response: no suitable HttpMessageConverter found for response type [interface org.springframework.web.multipart.MultipartFile] and content type [multipart/mixed;boundary=ML_BOUNDARY_10842596526049964806]
Thoughts?