java HttpClient asynchronous error handling

Question

I want to use Java Http Client: java.net.http.HttpClient in asynchronous way. When I receive http response (any http code) or timeout I want to execute some custom Java code. I struggle to complete the body of error handling.

CompletableFuture<HttpResponse<String>> response =
httpClient.sendAsync(request, HttpResponse.BodyHandlers.ofString())
  .thenApplyAsync(body -> {
    System.out.println("Request finished");
    return body;
  })
  .exceptionallyAsync(exception -> {

     // WHAT TO RETURN HERE ?      
  });

The method: exceptionallyAsync returns: CompletableFuture<T>, but I do not know how to complete this method.

Can you please help me to finish this method? I cannot find example in GitHub or Google.

Answer 1

You can use

.exceptionally(this::handlError)

If this is your response handler with a method like:

    private Void handlError(Throwable ex) {
        System.out.println(ex.toString());
        return null;
    }