Added files for BAEL-2044 (eugenp#6296)

core-java-11/src/main/java/com/baeldung/java11/httpclient/HttpClientExample.java

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+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+package com.baeldung.java11.httpclient;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpClient.Version;
+import java.net.http.HttpRequest;
+import java.net.http.HttpRequest.BodyPublishers;
+import java.net.http.HttpResponse;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.net.http.HttpResponse.PushPromiseHandler;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+
+public class HttpClientExample {
+
+    public static void main(String[] args) throws Exception {
+        httpGetRequest();
+        httpPostRequest();
+        asynchronousGetRequest();
+        asynchronousMultipleRequests();
+        pushRequest();
+    }
+
+    public static void httpGetRequest() throws URISyntaxException, IOException, InterruptedException {
+        HttpClient client = HttpClient.newHttpClient();
+        HttpRequest request = HttpRequest.newBuilder()
+            .version(HttpClient.Version.HTTP_2)
+            .uri(URI.create("http://jsonplaceholder.typicode.com/posts/1"))
+            .headers("Accept-Enconding", "gzip, deflate")
+            .build();
+        HttpResponse<String> response = client.send(request, BodyHandlers.ofString());
+
+        String responseBody = response.body();
+        int responseStatusCode = response.statusCode();
+
+        System.out.println("httpGetRequest: " + responseBody);
+        System.out.println("httpGetRequest status code: " + responseStatusCode);
+    }
+
+    public static void httpPostRequest() throws URISyntaxException, IOException, InterruptedException {
+        HttpClient client = HttpClient.newBuilder()
+            .version(HttpClient.Version.HTTP_2)
+            .build();
+        HttpRequest request = HttpRequest.newBuilder(new URI("http://jsonplaceholder.typicode.com/posts"))
+            .version(HttpClient.Version.HTTP_2)
+            .POST(BodyPublishers.ofString("Sample Post Request"))
+            .build();
+        HttpResponse<String> response = client.send(request, BodyHandlers.ofString());
+        String responseBody = response.body();
+        System.out.println("httpPostRequest : " + responseBody);
+    }
+
+    public static void asynchronousGetRequest() throws URISyntaxException {
+        HttpClient client = HttpClient.newHttpClient();
+        URI httpURI = new URI("http://jsonplaceholder.typicode.com/posts/1");
+        HttpRequest request = HttpRequest.newBuilder(httpURI)
+            .version(HttpClient.Version.HTTP_2)
+            .build();
+        CompletableFuture<Void> futureResponse = client.sendAsync(request, HttpResponse.BodyHandlers.ofString())
+            .thenAccept(resp -> {
+                System.out.println("Got pushed response " + resp.uri());
+                System.out.println("Response statuscode: " + resp.statusCode());
+                System.out.println("Response body: " + resp.body());
+            });
+        System.out.println("futureResponse" + futureResponse);
+
+    }
+
+    public static void asynchronousMultipleRequests() throws URISyntaxException {
+        HttpClient client = HttpClient.newHttpClient();
+        List<URI> uris = Arrays.asList(new URI("http://jsonplaceholder.typicode.com/posts/1"), new URI("http://jsonplaceholder.typicode.com/posts/2"));
+        List<HttpRequest> requests = uris.stream()
+            .map(HttpRequest::newBuilder)
+            .map(reqBuilder -> reqBuilder.build())
+            .collect(Collectors.toList());
+        System.out.println("Got pushed response1 " + requests);
+        CompletableFuture.allOf(requests.stream()
+            .map(request -> client.sendAsync(request, BodyHandlers.ofString()))
+            .toArray(CompletableFuture<?>[]::new))
+            .thenAccept(System.out::println)
+            .join();
+    }
+
+    public static void pushRequest() throws URISyntaxException, InterruptedException {
+        System.out.println("Running HTTP/2 Server Push example...");
+
+        HttpClient httpClient = HttpClient.newBuilder()
+            .version(Version.HTTP_2)
+            .build();
+
+        HttpRequest pageRequest = HttpRequest.newBuilder()
+            .uri(URI.create("https://http2.golang.org/serverpush"))
+            .build();
+
+        // Interface HttpResponse.PushPromiseHandler<T>
+        // void applyPushPromise​(HttpRequest initiatingRequest, HttpRequest pushPromiseRequest, Function<HttpResponse.BodyHandler<T>,​CompletableFuture<HttpResponse<T>>> acceptor)
+        httpClient.sendAsync(pageRequest, BodyHandlers.ofString(), pushPromiseHandler())
+            .thenAccept(pageResponse -> {
+                System.out.println("Page response status code: " + pageResponse.statusCode());
+                System.out.println("Page response headers: " + pageResponse.headers());
+                String responseBody = pageResponse.body();
+                System.out.println(responseBody);
+            }).join();
+
+        Thread.sleep(1000); // waiting for full response
+    }
+
+    private static PushPromiseHandler<String> pushPromiseHandler() {
+        return (HttpRequest initiatingRequest, 
+            HttpRequest pushPromiseRequest, 
+            Function<HttpResponse.BodyHandler<String>, 
+            CompletableFuture<HttpResponse<String>>> acceptor) -> {
+            acceptor.apply(BodyHandlers.ofString())
+                .thenAccept(resp -> {
+                    System.out.println(" Pushed response: " + resp.uri() + ", headers: " + resp.headers());
+                });
+            System.out.println("Promise request: " + pushPromiseRequest.uri());
+            System.out.println("Promise request: " + pushPromiseRequest.headers());
+        };
+    }
+
+}

core-java-11/src/test/java/com/baeldung/java11/httpclient/test/HttpClientTest.java

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+package com.baeldung.java11.httpclient.test;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import java.io.IOException;
+import java.net.Authenticator;
+import java.net.CookieManager;
+import java.net.CookiePolicy;
+import java.net.HttpURLConnection;
+import java.net.PasswordAuthentication;
+import java.net.ProxySelector;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CompletionException;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.stream.Collectors;
+
+import org.junit.jupiter.api.Test;
+
+public class HttpClientTest {
+
+    @Test
+    public void shouldReturnSampleDataContentWhenConnectViaSystemProxy() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyPublishers.ofString("Sample body"))
+            .build();
+
+
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .proxy(ProxySelector.getDefault())
+            .build()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.body(), containsString("Sample body"));
+    }
+
+    @Test
+    public void shouldNotFollowRedirectWhenSetToDefaultNever() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("http://stackoverflow.com"))
+            .version(HttpClient.Version.HTTP_1_1)
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .build()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_MOVED_PERM));
+        assertThat(response.body(), containsString("https://stackoverflow.com/"));
+    }
+
+    @Test
+    public void shouldFollowRedirectWhenSetToAlways() throws IOException, InterruptedException, URISyntaxException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("http://stackoverflow.com"))
+            .version(HttpClient.Version.HTTP_1_1)
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .followRedirects(HttpClient.Redirect.ALWAYS)
+            .build()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response.request()
+            .uri()
+            .toString(), equalTo("https://stackoverflow.com/"));
+    }
+
+    @Test
+    public void shouldReturnOKStatusForAuthenticatedAccess() throws URISyntaxException, IOException, InterruptedException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/basic-auth"))
+            .GET()
+            .build();
+        HttpResponse<String> response = HttpClient.newBuilder()
+            .authenticator(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication("postman", "password".toCharArray());
+                }
+            })
+            .build()
+            .send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldSendRequestAsync() throws URISyntaxException, InterruptedException, ExecutionException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/post"))
+            .headers("Content-Type", "text/plain;charset=UTF-8")
+            .POST(HttpRequest.BodyPublishers.ofString("Sample body"))
+            .build();
+        CompletableFuture<HttpResponse<String>> response = HttpClient.newBuilder()
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandlers.ofString());
+
+        assertThat(response.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldUseJustTwoThreadWhenProcessingSendAsyncRequest() throws URISyntaxException, InterruptedException, ExecutionException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        ExecutorService executorService = Executors.newFixedThreadPool(2);
+
+        CompletableFuture<HttpResponse<String>> response1 = HttpClient.newBuilder()
+            .executor(executorService)
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandlers.ofString());
+
+        CompletableFuture<HttpResponse<String>> response2 = HttpClient.newBuilder()
+            .executor(executorService)
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandlers.ofString());
+
+        CompletableFuture<HttpResponse<String>> response3 = HttpClient.newBuilder()
+            .executor(executorService)
+            .build()
+            .sendAsync(request, HttpResponse.BodyHandlers.ofString());
+
+        CompletableFuture.allOf(response1, response2, response3)
+            .join();
+
+        assertThat(response1.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response2.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+        assertThat(response3.get()
+            .statusCode(), equalTo(HttpURLConnection.HTTP_OK));
+    }
+
+    @Test
+    public void shouldNotStoreCookieWhenPolicyAcceptNone() throws URISyntaxException, IOException, InterruptedException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        HttpClient httpClient = HttpClient.newBuilder()
+            .cookieHandler(new CookieManager(null, CookiePolicy.ACCEPT_NONE))
+            .build();
+
+        httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertTrue(httpClient.cookieHandler()
+            .isPresent());
+    }
+
+    @Test
+    public void shouldStoreCookieWhenPolicyAcceptAll() throws URISyntaxException, IOException, InterruptedException {
+        HttpRequest request = HttpRequest.newBuilder()
+            .uri(new URI("https://postman-echo.com/get"))
+            .GET()
+            .build();
+
+        HttpClient httpClient = HttpClient.newBuilder()
+            .cookieHandler(new CookieManager(null, CookiePolicy.ACCEPT_ALL))
+            .build();
+
+        httpClient.send(request, HttpResponse.BodyHandlers.ofString());
+
+        assertTrue(httpClient.cookieHandler()
+            .isPresent());
+    }
+
+    @Test
+    public void shouldProcessMultipleRequestViaStream() throws URISyntaxException, ExecutionException, InterruptedException {
+        List<URI> targets = Arrays.asList(new URI("https://postman-echo.com/get?foo1=bar1"), new URI("https://postman-echo.com/get?foo2=bar2"));
+
+        HttpClient client = HttpClient.newHttpClient();
+
+        List<CompletableFuture<String>> futures = targets.stream()
+            .map(target -> client.sendAsync(HttpRequest.newBuilder(target)
+                .GET()
+                .build(), HttpResponse.BodyHandlers.ofString())
+                .thenApply(response -> response.body()))
+            .collect(Collectors.toList());
+
+        CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]))
+            .join();
+
+        if (futures.get(0)
+            .get()
+            .contains("foo1")) {
+            assertThat(futures.get(0)
+                .get(), containsString("bar1"));
+            assertThat(futures.get(1)
+                .get(), containsString("bar2"));
+        } else {
+            assertThat(futures.get(1)
+                .get(), containsString("bar2"));
+            assertThat(futures.get(1)
+                .get(), containsString("bar1"));
+        }
+
+    }
+
+    @Test
+    public void completeExceptionallyExample() {
+        CompletableFuture<String> cf = CompletableFuture.completedFuture("message").thenApplyAsync(String::toUpperCase,
+                CompletableFuture.delayedExecutor(1, TimeUnit.SECONDS));
+        CompletableFuture<String> exceptionHandler = cf.handle((s, th) -> { return (th != null) ? "message upon cancel" : ""; });
+        cf.completeExceptionally(new RuntimeException("completed exceptionally"));
+        assertTrue("Was not completed exceptionally", cf.isCompletedExceptionally());
+        try {
+            cf.join();
+            fail("Should have thrown an exception");
+        } catch (CompletionException ex) { // just for testing
+            assertEquals("completed exceptionally", ex.getCause().getMessage());
+        }
+
+        assertEquals("message upon cancel", exceptionHandler.join());
+    }
+
+}