👀 Views: 440 💬 Answers: 1 📅 Created: 2025-10-17

spring-boot asynchronous rest-api Java

Hey everyone, I'm running into an issue that's driving me crazy. After trying multiple solutions online, I still can't figure this out. Could someone explain I'm having trouble with Integrating a third-party API into a legacy Spring Boot application has proven to be quite a challenge. The existing implementation uses synchronous calls that block the thread, leading to performance issues. As part of the refactor, I want to transition to using asynchronous calls but I'm unsure about the best approach. My current method looks like this: ```java @RestController public class ApiController { @Autowired private RestTemplate restTemplate; @GetMapping("/data") public ResponseEntity<String> getData() { String response = restTemplate.getForObject("https://api.example.com/data", String.class); return ResponseEntity.ok(response); } } ``` This synchronously waits for the API response, which isn't ideal considering our performance benchmarks. I’ve read that using `CompletableFuture` can help with this: ```java @GetMapping("/data") public CompletableFuture<ResponseEntity<String>> getDataAsync() { return CompletableFuture.supplyAsync(() -> restTemplate.getForObject("https://api.example.com/data", String.class)) .thenApply(ResponseEntity::ok); } ``` However, I'm not sure how to handle potential exceptions that might arise from the API call. Should I wrap the `supplyAsync` in a try-catch block, or is there a better pattern for error handling in this context? Additionally, I’m aware that Spring WebFlux also exists, which offers a non-blocking way to handle requests. Would it be worth considering a complete overhaul to use WebFlux for this integration? My team is familiar with Spring MVC, but the performance gains from non-blocking IO are tempting. Any insights on best practices for managing asynchronous calls within a legacy Spring Boot application, especially around error handling and whether to switch to WebFlux for this case? I'm using Java 3.10 in this project. I'm on CentOS using the latest version of Java. This is my first time working with Java latest. This is for a application running on macOS. Any advice would be much appreciated.