only heat a URI, not wait for responce in Spring Rest

Question

Suppose I click on URI localhost:8080/admin/hello with Hello class POST JSON object using POSTMAN and have a Controller like,

@RequestMapping(value = "/hello", method = RequestMethod.POST)
public ResponseEntity<Hello> helloHome(@RequestBody Hello obj){
//here it goes to service class and doing processes...
return new ResponseEntity<Hello>(obj, HttpStatus.OK);
}

I only want the URI to hit the Controller but not wait for response (because processing all the service class process takes 10 seconds but I want to return immediate without response).

How can I implement it?

Answer 1

You can enable Async processing by enabling it via your config.

@Configuration
@EnableAsync
public class YourConfig

Now you can add a service and enable async processing on one of its methods by annotating it with @Async. It will return immediately after it was called.

@Async
public void asyncMethodOnAService() {}

If you want to service to return a value you can return a CompletableFuture

@Async
public CompletableFuture<String> asyncMethodOnAService() {}

The controller that call the async method can return a DeferredResult which will let the client know that the result will be available once the async processing has finished.

    @RequestMapping(value = "/async", method = RequestMethod.GET)
    public DeferredResult<ResponseEntity<String>> doAsync() {

      DeferredResult<ResponseEntity<String>> result = new DeferredResult<>();
      this.asyncService.asyncMethodOnAService().whenComplete((serviceResult, throwable) -> result.setResult(ResponseEntity.ok(serviceResult)));

      return result;
    }