这是 Java 9 开始引入的一个处理 HTTP 请求的的 HTTP Client API，该 API 支持同步和异步，而在 Java 11 中已经为正式可用状态，你可以在 java.net 包中找到这个 API。

来看一下 HTTP Client 的用法：

var request = HttpRequest.newBuilder()

.uri(URI.create("https://javastack.cn"))

.GET()

.build();

var client = HttpClient.newHttpClient();

// 同步

HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());

System.out.println(response.body());

// 异步

client.sendAsync(request, HttpResponse.BodyHandlers.ofString())

.thenApply(HttpResponse::body)

.thenAccept(System.out::println);

上面的 .GET() 可以省略，默认请求方式为 Get！

例子：

import static org.junit.Assert.*;

import java.net.URI;

import java.net.http.HttpClient;

import java.net.http.HttpRequest;

import java.net.http.HttpResponse;

import java.net.http.HttpResponse.BodyHandler;

import java.net.http.HttpResponse.BodyHandlers;

import java.util.concurrent.CompletableFuture;

import org.junit.Test;

public class HTTPClientTest {

	@Test

	public void testName2() throws Exception {

		HttpClient client = HttpClient.newHttpClient();

		HttpRequest request = HttpRequest.newBuilder(URI.create("http://127.0.0.1:8080/test/")).build();

		BodyHandler<String> responseBodyHandler = BodyHandlers.ofString();

		CompletableFuture<HttpResponse<String>> sendAsync = client.sendAsync(request, responseBodyHandler);

		sendAsync.thenApply(t -> t.body()).thenAccept(System.out::println);

		//HttpResponse<String> response = sendAsync.get();

		//String body = response.body();

		//System.out.println(body);

	}

	@Test

	public void testName() throws Exception {

		HttpClient client = HttpClient.newHttpClient();

		HttpRequest request = HttpRequest.newBuilder(URI.create("http://127.0.0.1:8080/test/")).build();

		BodyHandler<String> responseBodyHandler = BodyHandlers.ofString();

		HttpResponse<String> response = client.send(request, responseBodyHandler);

		String body = response.body();

		System.out.println(body);

	}

}