JDK11的新特性之-新的HTTP API

使用HTTP Client请求的基本流程

通常我们要在代码中做一个HTTP请求，通常有三个步骤。

构建一个HTTP client。
生成一个HTTP Request。
使用HTTP Client发送HTTP Request得到一个HTTP Response。

下面开始给出示例

1.发出GET的同步请求

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpHeaders;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;

public class HttpClientSynchronous {

//创建client
    private static final HttpClient httpClient = HttpClient.newBuilder()
            .version(HttpClient.Version.HTTP_1_1)
//超时时间10s
            .connectTimeout(Duration.ofSeconds(10))
            .build();

    public static void main(String[] args) throws IOException, InterruptedException {

//创建request, 创建GET请求
        HttpRequest request = HttpRequest.newBuilder()
                .GET()
                .uri(URI.create("https://httpbin.org/get"))
                .setHeader("User-Agent", "Java 11 HttpClient Bot") // add request header
                .build();

//发送同步请求
        HttpResponse response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());

        // print response headers
        HttpHeaders headers = response.headers();
        headers.map().forEach((k, v) -> System.out.println(k + ":" + v));

        // print status code
        System.out.println(response.statusCode());

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

    }

}

2.发送GET的异步请求

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.TimeUnit;
import java.time.Duration;

public class HttpClientAsynchronous {

    private static final HttpClient httpClient = HttpClient.newBuilder()
            .version(HttpClient.Version.HTTP_2)
            .connectTimeout(Duration.ofSeconds(10))
            .build();

    public static void main(String[] args) throws Exception {

        HttpRequest request = HttpRequest.newBuilder()
                .GET()
                .uri(URI.create("https://httpbin.org/get"))
                .setHeader("User-Agent", "Java 11 HttpClient Bot")
                .build();

//发送异步请求
        CompletableFuture> response =
                httpClient.sendAsync(request, HttpResponse.BodyHandlers.ofString());

        String result = response.thenApply(HttpResponse::body).get(5, TimeUnit.SECONDS);

        System.out.println(result);

    }

}

3.使用线程池发送请求

private final ExecutorService executorService = Executors.newFixedThreadPool(5);

  private final HttpClient httpClient = HttpClient.newBuilder()
          .executor(executorService)
          .build();

4.异步发送多个GET并发请求

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.stream.Collectors;
import java.time.Duration;

public class HttpClientCustomExecutor {

    // custom executor
    private static final ExecutorService executorService = Executors.newFixedThreadPool(5);

    private static final HttpClient httpClient = HttpClient.newBuilder()
            .executor(executorService)
            .version(HttpClient.Version.HTTP_2)
            .connectTimeout(Duration.ofSeconds(10))
            .build();

    public static void main(String[] args) throws Exception {

        List targets = Arrays.asList(
                new URI("https://httpbin.org/get?name=mkyong1"),
                new URI("https://httpbin.org/get?name=mkyong2"),
                new URI("https://httpbin.org/get?name=mkyong3"));

//异步并发发送
        List> result = targets.stream()
                .map(url -> httpClient.sendAsync(
                        HttpRequest.newBuilder(url)
                                .GET()
                                .setHeader("User-Agent", "Java 11 HttpClient Bot")
                                .build(),
                        HttpResponse.BodyHandlers.ofString())
                        .thenApply(response -> response.body()))
                .collect(Collectors.toList());

        for (CompletableFuture future : result) {
            System.out.println(future.get());
        }

    }

}

5.发送POST Form表单的参数

import java.io.IOException;
import java.net.URI;
import java.net.URLEncoder;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.util.HashMap;
import java.util.Map;

public class HttpClientPostForm {

    private static final HttpClient httpClient = HttpClient.newBuilder()
            .version(HttpClient.Version.HTTP_2)
            .connectTimeout(Duration.ofSeconds(10))
            .build();

    public static void main(String[] args) throws IOException, InterruptedException {

        // form参数
        Map data = new HashMap<>();
        data.put("username", "abc");
        data.put("password", "123");
        data.put("custom", "secret");
        data.put("ts", System.currentTimeMillis());

        HttpRequest request = HttpRequest.newBuilder()
//POST请求
                .POST(ofFormData(data))
                .uri(URI.create("https://httpbin.org/post"))
                .setHeader("User-Agent", "Java 11 HttpClient Bot") // add request header
//post的请求
                .header("Content-Type", "application/x-www-form-urlencoded")
                .build();

//同步发送
        HttpResponse response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());

        // print status code
        System.out.println(response.statusCode());

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

    }

    // Sample: 'password=123&custom=secret&username=abc&ts=1570704369823'
//设置form参数form
    public static HttpRequest.BodyPublisher ofFormData(Map data) {
        var builder = new StringBuilder();
        for (Map.Entry entry : data.entrySet()) {
            if (builder.length() > 0) {
                builder.append("&");
            }
            builder.append(URLEncoder.encode(entry.getKey().toString(), StandardCharsets.UTF_8));
            builder.append("=");
            builder.append(URLEncoder.encode(entry.getValue().toString(), StandardCharsets.UTF_8));
        }
        return HttpRequest.BodyPublishers.ofString(builder.toString());
    }

}

6.发送POST的JSON数据

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;

public class HttpClientPostJSON {

    private static final HttpClient httpClient = HttpClient.newBuilder()
            .version(HttpClient.Version.HTTP_2)
            .connectTimeout(Duration.ofSeconds(10))
            .build();

    public static void main(String[] args) throws IOException, InterruptedException {

        // json数据
        String json = new StringBuilder()
                .append("{")
                .append(""name":"mkyong",")
                .append(""notes":"hello"")
                .append("}").toString();

        // add json header
        HttpRequest request = HttpRequest.newBuilder()
                .POST(HttpRequest.BodyPublishers.ofString(json))
                .uri(URI.create("https://httpbin.org/post"))
                .setHeader("User-Agent", "Java 11 HttpClient Bot") // add request header
//JSON的请求头
                .header("Content-Type", "application/json")
                .build();

        HttpResponse response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());

        // print status code
        System.out.println(response.statusCode());

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

    }

}

7.启动一个简单的 Spring Security WebApp 提供 HTTP 基本身份验证，并使用新的 Java 11 HttpClient API 对其进行测试

import java.io.IOException;
import java.net.Authenticator;
import java.net.PasswordAuthentication;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;


public class HttpClientAuthentication {

    private static final HttpClient httpClient = HttpClient.newBuilder()
            .authenticator(new Authenticator() {
//授权信息
                @Override
                protected PasswordAuthentication getPasswordAuthentication() {
                    return new PasswordAuthentication(
                            "user",
                            "password".toCharArray());
                }

            })
            .connectTimeout(Duration.ofSeconds(10))
            .build();

    public static void main(String[] args) throws IOException, InterruptedException {

        HttpRequest request = HttpRequest.newBuilder()
                .GET()
                .uri(URI.create("http://localhost:8080/books"))
                .setHeader("User-Agent", "Java 11 HttpClient Bot") // add request header
                .build();

        HttpResponse response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());

        // print status code
        System.out.println(response.statusCode());

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

    }

}

8.禁用重定向

private final HttpClient httpClient = HttpClient.newBuilder()
//不重定向
            .followRedirects(HttpClient.Redirect.NEVER)
            .build();

9.设置代理信息

private final HttpClient httpClient = HttpClient.newBuilder()
//设置代理信息
            .proxy(ProxySelector.of(new InetSocketAddress("your-company-proxy.com", 8080)))
            .build();

JDK11的新特性之-新的HTTP API

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