Simple example to call Async RestTemplate :
https://github.com/devwebcl/async-springmvc-poc
Most important snippet code:
public AsyncRestTemplate asyncRestTemplateFactory() {
PoolingHttpClientConnectionManager connManager = new PoolingHttpClientConnectionManager();
connManager.setMaxTotal(maxTotalConnections);
connManager.setDefaultMaxPerRoute(maxConnectionsPerRoute);
CloseableHttpClient httpClient = HttpClientBuilder.create().setConnectionManager(connManager).build();
HttpComponentsAsyncClientHttpRequestFactory requestAsyncFactory =
new HttpComponentsAsyncClientHttpRequestFactory();
requestAsyncFactory.setConnectionRequestTimeout(connectRequestTimeout);
requestAsyncFactory.setConnectTimeout(connectTimeout);
requestAsyncFactory.setReadTimeout(readTimeout);
requestAsyncFactory.setHttpClient(httpClient);
AsyncRestTemplate art = new AsyncRestTemplate();
art.setAsyncRequestFactory(requestAsyncFactory);
//deberia ser inyectado desde DI container
return new AsyncRestTemplate(requestAsyncFactory);
}
and
public String callback() throws Exception {
Map<String, ListenableFuture<ResponseEntity<String>>> futures = new HashMap<>(); //podria ser un Guava Table
List<String> respuestas = new ArrayList<>();
AsyncFactory af = new AsyncFactory();
AsyncRestTemplate artf = af.asyncRestTemplateFactory();
//url a visitar
String[] url = {"http://google.com", "http://bing.com", "https://stackoverflow.com/", "https://www.infoq.com/", "https://dzone.com/",
"https://jakarta.ee/", "https://www.eclipse.org/", "http://www.noexisto.cl/", "https://spring.io/", "https://github.com/",
"https://www.apache.org/"};
//agrego llamadas asincronas
for(int i=0; i<url.length; i++) {
HttpMethod method = HttpMethod.GET;
Class<String> responseType = String.class;
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.TEXT_PLAIN);
HttpEntity<String> requestEntity = new HttpEntity<>("params", headers);
//la llave es la misma url (modificable)
// usar DeferredResult ?
ListenableFuture<ResponseEntity<String>> future = artf.exchange(url[i], method, requestEntity, responseType);
// es "opcional"
future.addCallback(new ListenableFutureCallback<ResponseEntity<String>>() {
@Override
public void onSuccess(ResponseEntity<String> result) {
System.out.println("onSuccess " + result.getHeaders() );
//TODO: DeferredResult ?
}
@Override
public void onFailure(Throwable ex) {
System.out.println("onFailure!!! " + ex );
}
});
futures.put(url[i], future);
}
//TODO: borrar !
// duermo los hilos solo por prueba:
int segundos_sleep = 2;
System.out.println("durmiendo por " + segundos_sleep + " segundos...");
Thread.sleep(segundos_sleep * 1000);
int i=0;
//voy uno a uno... con Guava SuccessfulAsList seria lo mismo al final ya que quiero cada uno de los responses
for (Map.Entry<String, ListenableFuture<ResponseEntity<String>>> llave : futures.entrySet()) {
System.out.println((++i)+". -----------------------------------------------------\n");
System.out.println("key = " + llave.getKey() + ",\n value = " + llave.getValue());
ListenableFuture<ResponseEntity<String>> future = llave.getValue();
ResponseEntity<String> entity = null;
try {
entity = future.get(); // blocking en cada uno, pero la respuesta ya puede existir
} catch (InterruptedException ie) {
ie.printStackTrace();
continue;
} catch (ExecutionException ee) {
ee.printStackTrace();
continue;
}
String headers = entity.getHeaders().toString();
if(headers.indexOf("domain=")!=-1)
System.out.println(headers.substring(headers.indexOf("; domain=")));
else
System.out.println(headers);
System.out.println(entity.getStatusCode());
//System.out.println(entity.getBody());
respuestas.add(entity.getBody().toString());
System.out.println("isDone? " + future.isDone() + "\n");
}
System.out.println("\nfin.");
//return respuestas;
return "done";
}
Lista IMDb
9 years ago
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