HTTP Client

Definition

Java 11 made java.net.http.HttpClient a standard part of Java. It sends HTTP requests, supports HTTP/2, and can work synchronously or asynchronously, so you no longer need an extra library for simple calls.

Example code

Calling a small local server (so it runs without internet)

import com.sun.net.httpserver.HttpServer;
import java.net.InetSocketAddress;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

class Demo {
    public static void main(String[] args) throws Exception {
        HttpServer server = HttpServer.create(new InetSocketAddress(0), 0);   // a tiny server for the example
        server.createContext("/hello", exchange -> {
            byte[] body = "Hello from the server".getBytes();
            exchange.sendResponseHeaders(200, body.length);
            exchange.getResponseBody().write(body);
            exchange.close();
        });
        server.start();

        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder(
                URI.create("http://localhost:" + server.getAddress().getPort() + "/hello")).build();

        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println(response.statusCode() + " " + response.body());
        server.stop(0);
    }
}

// Output:
// 200 Hello from the server