Multiple REST Calls using Spring Boot

Question

I'm trying to make 500+ REST calls (POST) to an API using Spring Boot. Currently I'm using a thread pool using callable - executor service since I require the response from the POST call as well. Is there a more efficient way to do this within Spring Boot? edit - This is a IO Intensive Task

Answer 1

You can simply use WebClient, as it's non-blocking by design.

see e.g.: https://newbedev.com/springboot-how-to-use-webclient-instead-of-resttemplate-for-performing-non-blocking-and-asynchronous-calls But there are lots of other resources on the web.

However... if you're using RestTemplate:

@Service
public class AsyncService {

    private final RestTemplate restTemplate;

    public AsyncService(RestTemplate restTemplate) {
        this.restTemplate = restTemplate;
    }

    @Async
    public CompletableFuture<ResponseDto[]> callAsync(RequestDto requestDto) {
        ResponseDto[] responseDtos = restTemplate.postForObject("someUrl", requestDto, ResponseDto[].class);
        
        return CompletableFuture.completedFuture(responseDtos);
    }
}

Then you can simply loop though all requests from whatever place is ideal for your context using standard Java Future mechanisms.

Just make sure to add @EnableAsync to your application

A more detailed tutorial can be found here: https://spring.io/guides/gs/async-method/