How to measure the elapsed time of ASYNC sent HTTPRequest with Java 11 standard HTTPClient?

Question

In one method, I create and send some HTTPRequests async, and add the CF to a list:

// HTTPClient is Java11 standard, package java.net.http;
CompletableFuture<HttpResponse<String>> httpResponseCF = this.httpClient.sendAsync(httpRequest, BodyHandlers.ofString());
list.add(httpResponseCF);

Later, in another method, I periodically check every 1second if some of my async sent HTTPRequests have already received:

for(CompletableFuture<HttpResponse<String>> httpResponseCF : list){
  if (httpResponseCF.isDone()) {
    //print out: The time between sending HTTPRequest and receiving HTTPResponse is 25ms
  }
}

The question is, how to measure the exact elapsed request-time?

score 1 · Accepted Answer · answered Jun 02 '20 at 12:48

Something like the following should do the trick:

long start = System.nanoTime();
CompletableFuture<HttpResponse<String>> httpResponseCF = 
    this.httpClient.sendAsync(httpRequest, BodyHandlers.ofString()).
    whenComplete((r,t) -> System.out.println("elapsed ns: "
                           + (System.nanoTime() - start)));

Disclaimer: I haven't actually compiled the above... It's also not the exact time but the best approximation you can get. As with everything, the exact time is impossible to measure.

How to measure the elapsed time of ASYNC sent HTTPRequest with Java 11 standard HTTPClient?

1 Answers1