1. Overview
In this tutorial we’ll illustrate the most common use cases of the Apache HttpAsyncClient – from basic usage, to how to set up a proxy, how to use SSL certificate and finally – how to authenticate with the async client.
2. Simple Example
First – let’s see how to use HttpAsyncClient in a simple example – send a GET request:
@Test
void whenUseHttpAsyncClient_thenCorrect() throws InterruptedException, ExecutionException, IOException {
final SimpleHttpRequest request = SimpleRequestBuilder.get(HOST_WITH_COOKIE)
.build();
final CloseableHttpAsyncClient client = HttpAsyncClients.custom()
.build();
client.start();
final Future<SimpleHttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getCode(), equalTo(200));
client.close();
}
Note how we need to start the async client before using it; without that, we would get the following exception:
java.lang.IllegalStateException: Request cannot be executed; I/O reactor status: INACTIVE
at o.a.h.u.Asserts.check(Asserts.java:46)
at o.a.h.i.n.c.CloseableHttpAsyncClientBase.
ensureRunning(CloseableHttpAsyncClientBase.java:90)
3. Multi-Threading With HttpAsyncClient
Now – let’s see how to use HttpAsyncClient to execute multiple requests simultaneously.
In the following example – we send three GET requests to three different host using HttpAsyncClient .
3.1. For HttpAsyncClient 5.x
@Test
void whenUseMultipleHttpAsyncClient_thenCorrect() throws Exception {
final IOReactorConfig ioReactorConfig = IOReactorConfig
.custom()
.build();
final CloseableHttpAsyncClient client = HttpAsyncClients.custom()
.setIOReactorConfig(ioReactorConfig)
.build();
client.start();
final String[] toGet = { "http://www.google.com/", "http://www.apache.org/", "http://www.bing.com/" };
final GetThread[] threads = new GetThread[toGet.length];
for (int i = 0; i < threads.length; i++) {
final HttpGet request = new HttpGet(toGet[i]);
threads[i] = new GetThread(client, request);
}
for (final GetThread thread : threads) {
thread.start();
}
for (final GetThread thread : threads) {
thread.join();
}
}
Here is our GetThread implementation to handle the response:
static class GetThread extends Thread {
private final CloseableHttpAsyncClient client;
private final HttpContext context;
private final HttpGet request;
GetThread(final CloseableHttpAsyncClient client, final HttpGet request) {
this.client = client;
context = HttpClientContext.create();
this.request = request;
}
@Override
public void run() {
try {
final Future<HttpResponse> future = client.execute(request, context, null);
final HttpResponse response = future.get();
assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
} catch (final Exception ex) {
System.out.println(ex.getLocalizedMessage());
}
}
}
3.2. For HttpAsyncClient 4.5
@Test
void whenUseMultipleHttpAsyncClient_thenCorrect() throws Exception {
final ConnectingIOReactor ioReactor = new DefaultConnectingIOReactor();
final PoolingNHttpClientConnectionManager cm = new PoolingNHttpClientConnectionManager(ioReactor);
final CloseableHttpAsyncClient client = HttpAsyncClients.custom().setConnectionManager(cm).build();
client.start();
final String[] toGet = { "http://www.google.com/", "http://www.apache.org/", "http://www.bing.com/" };
final GetThread[] threads = new GetThread[toGet.length];
for (int i = 0; i < threads.length; i++) {
final HttpGet request = new HttpGet(toGet[i]);
threads[i] = new GetThread(client, request);
}
for (final GetThread thread : threads) {
thread.start();
}
for (final GetThread thread : threads) {
thread.join();
}
}
4. Proxy With HttpAsyncClient
Let’s see how to set up and use a proxy with the HttpAsyncClient.
In the following example – we send a HTTP GET request over proxy.
4.1. For HttpAsyncClient 5.x
@Test
void whenUseProxyWithHttpClient_thenCorrect() throws Exception {
final HttpHost proxy = new HttpHost("127.0.0.1", GetRequestMockServer.serverPort);
DefaultProxyRoutePlanner routePlanner = new DefaultProxyRoutePlanner(proxy);
final CloseableHttpAsyncClient client = HttpAsyncClients.custom()
.setRoutePlanner(routePlanner)
.build();
client.start();
final SimpleHttpRequest request = new SimpleHttpRequest("GET" ,HOST_WITH_PROXY);
final Future<SimpleHttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getCode(), equalTo(200));
client.close();
}
4.2. For HttpAsyncClient 4.5
@Test
void whenUseProxyWithHttpClient_thenCorrect() throws Exception {
final CloseableHttpAsyncClient client = HttpAsyncClients.createDefault();
client.start();
final HttpHost proxy = new HttpHost("127.0.0.1", GetRequestMockServer.serverPort);
final RequestConfig config = RequestConfig.custom().setProxy(proxy).build();
final HttpGet request = new HttpGet(HOST_WITH_PROXY);
request.setConfig(config);
final Future<HttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
client.close();
}
5. SSL Certificate With HttpAsyncClient
Now – let’s see how to use a SSL Certificate with HttpAsyncClient.
In the following example – we configure HttpAsyncClient to accept all certificates:
5.1. For HttpAsyncClient 5.x
@Test
void whenUseSSLWithHttpAsyncClient_thenCorrect() throws Exception {
final TrustStrategy acceptingTrustStrategy = (certificate, authType) -> true;
final SSLContext sslContext = SSLContexts.custom()
.loadTrustMaterial(null, acceptingTrustStrategy)
.build();
final TlsStrategy tlsStrategy = ClientTlsStrategyBuilder.create()
.setHostnameVerifier(NoopHostnameVerifier.INSTANCE)
.setSslContext(sslContext)
.build();
final PoolingAsyncClientConnectionManager cm = PoolingAsyncClientConnectionManagerBuilder.create()
.setTlsStrategy(tlsStrategy)
.build();
final CloseableHttpAsyncClient client = HttpAsyncClients.custom()
.setConnectionManager(cm)
.build();
client.start();
final SimpleHttpRequest request = new SimpleHttpRequest("GET",HOST_WITH_SSL);
final Future<SimpleHttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getCode(), equalTo(200));
client.close();
}
5.2. For HttpAsyncClient 4.5
@Test
void whenUseSSLWithHttpAsyncClient_thenCorrect() throws Exception {
final TrustStrategy acceptingTrustStrategy = (certificate, authType) -> true;
final SSLContext sslContext = SSLContexts.custom()
.loadTrustMaterial(null, acceptingTrustStrategy)
.build();
final CloseableHttpAsyncClient client = HttpAsyncClients.custom()
.setSSLHostnameVerifier(NoopHostnameVerifier.INSTANCE)
.setSSLContext(sslContext).build();
client.start();
final HttpGet request = new HttpGet(HOST_WITH_SSL);
final Future<HttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
client.close();
}
6. Cookies With HttpAsyncClient
Next – let’s see how to use cookies with HttpAsyncClient.
In the following example – we set a cookie value before sending the request.
6.1. For HttpAsyncClient 5.x
@Test
void whenUseCookiesWithHttpAsyncClient_thenCorrect() throws Exception {
final BasicCookieStore cookieStore = new BasicCookieStore();
final BasicClientCookie cookie = new BasicClientCookie(COOKIE_NAME, "1234");
cookie.setDomain(COOKIE_DOMAIN);
cookie.setPath("/");
cookieStore.addCookie(cookie);
final CloseableHttpAsyncClient client = HttpAsyncClients.custom().build();
client.start();
final SimpleHttpRequest request = new SimpleHttpRequest("GET" ,HOST_WITH_COOKIE);
final HttpContext localContext = new BasicHttpContext();
localContext.setAttribute(HttpClientContext.COOKIE_STORE, cookieStore);
final Future<SimpleHttpResponse> future = client.execute(request, localContext, null);
final HttpResponse response = future.get();
assertThat(response.getCode(), equalTo(200));
client.close();
}
6.2. For HttpAsyncClient 4.5
@Test
void whenUseCookiesWithHttpAsyncClient_thenCorrect() throws Exception {
final BasicCookieStore cookieStore = new BasicCookieStore();
final BasicClientCookie cookie = new BasicClientCookie(COOKIE_NAME, "1234");
cookie.setDomain(COOKIE_DOMAIN);
cookie.setPath("/");
cookieStore.addCookie(cookie);
final CloseableHttpAsyncClient client = HttpAsyncClients.custom().build();
client.start();
final HttpGet request = new HttpGet(HOST_WITH_COOKIE);
final HttpContext localContext = new BasicHttpContext();
localContext.setAttribute(HttpClientContext.COOKIE_STORE, cookieStore);
final Future<HttpResponse> future = client.execute(request, localContext, null);
final HttpResponse response = future.get();
assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
client.close();
}
7. Authentication With HttpAsyncClient
Next – let’s see how to use authentication with HttpAsyncClient.
In the following example – we use the CredentialsProvider to access a host through basic authentication.
7.1. For HttpAsyncClient 5.x
@Test
void whenUseAuthenticationWithHttpAsyncClient_thenCorrect() throws Exception {
final BasicCredentialsProvider credsProvider = new BasicCredentialsProvider();
final UsernamePasswordCredentials credentials =
new UsernamePasswordCredentials(DEFAULT_USER, DEFAULT_PASS.toCharArray());
credsProvider.setCredentials(new AuthScope(URL_SECURED_BY_BASIC_AUTHENTICATION, 80) ,credentials);
final CloseableHttpAsyncClient client = HttpAsyncClients
.custom()
.setDefaultCredentialsProvider(credsProvider).build();
final SimpleHttpRequest request = new SimpleHttpRequest("GET" ,URL_SECURED_BY_BASIC_AUTHENTICATION);
client.start();
final Future<SimpleHttpResponse> future = client.execute(request, null);
final HttpResponse response = future.get();
assertThat(response.getCode(), equalTo(200));
client.close();
}
7.2. For HttpAsyncClient 4.5
@Test
public void whenUseAuthenticationWithHttpAsyncClient_thenCorrect() throws Exception {
CredentialsProvider provider = new BasicCredentialsProvider();
UsernamePasswordCredentials creds = new UsernamePasswordCredentials("user", "pass");
provider.setCredentials(AuthScope.ANY, creds);
CloseableHttpAsyncClient client =
HttpAsyncClients.custom().setDefaultCredentialsProvider(provider).build();
client.start();
HttpGet request = new HttpGet("http://localhost:8080");
Future<HttpResponse> future = client.execute(request, null);
HttpResponse response = future.get();
assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
client.close();
}
8. Conclusion
In this article, we illustrated the various use cases of the asynchronous Apache Http client.
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