关于人工智能:64-HttpClient

1. 什么是HttpClient？

HttpClient是Java 11中引入的一个新个性，用于反对同步和异步发送HTTP申请以及解决HTTP响应。它提供了简略易用的API，使得发送HTTP申请变得非常简单。

2. HttpClient的次要组件

HttpClient由以下几个次要组件组成：

• HttpClient：用于发送申请的次要类。
• HttpRequest：示意一个HTTP申请。
• HttpResponse：示意一个HTTP响应。

3. 发送GET申请

要应用HttpClient发送GET申请，能够创立一个HttpClient对象，而后创立一个HttpRequest对象并设置申请办法为GET。最初，应用HttpClient的send()办法发送申请并获取响应。以下是一个简略示例：

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class HttpClientGetExample {
    public static void main(String[] args) {
        try {
            HttpClient client = HttpClient.newHttpClient();
            HttpRequest request = HttpRequest.newBuilder()
                    .uri(URI.create("https://www.example.com/"))
                    .GET()
                    .build();

            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
            System.out.println(response.statusCode());
            System.out.println(response.body());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

4. 发送POST申请

要应用HttpClient发送POST申请，能够创立一个HttpClient对象，而后创立一个HttpRequest对象并设置申请办法为POST。还须要设置申请体，例如表单数据或JSON数据。最初，应用HttpClient的send()办法发送申请并获取响应。以下是一个简略示例：

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;

public class HttpClientPostExample {
    public static void main(String[] args) {
        try {
            HttpClient client = HttpClient.newHttpClient();
            String postData = "username=user&password=pass";
            HttpRequest request = HttpRequest.newBuilder()
                    .uri(URI.create("https://www.example.com/login"))
                    .header("Content-Type", "application/x-www-form-urlencoded")
                    .POST(HttpRequest.BodyPublishers.ofString(postData))
                    .build();

            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
            System.out.println(response.statusCode());
            System.out.println(response.body());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

5. 异步申请

HttpClient还反对异步发送HTTP申请。要发送异步申请，能够应用HttpClient的sendAsync()办法。以下是一个简略示例：

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class HttpClientAsyncExample {
    public static void main(String[] args) {
        try {
            HttpClient client = HttpClient.newHttpClient();
            HttpRequest request = HttpRequest.newBuilder()
                    .uri(URI.create("https://www.example.com/"))
                    .GET()
                    .build();

            client.sendAsync(request, HttpResponse.BodyHandlers.ofString())
                    .thenApply(HttpResponse::body)
                    .thenAccept(System.out::println)
                    .join();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

6. 自定义HttpClient

能够通过HttpClient.Builder类自定义HttpClient，例如设置超时、代理、重定向策略等。以下是一个简略示例，演示如何设置超时和代理：

import java.net.InetSocketAddress;
import java.net.ProxySelector;
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 CustomHttpClientExample {
    public static void main(String[] args) {
        try {
            HttpClient client = HttpClient.newBuilder()
                    .connectTimeout(Duration.ofSeconds(5))
                    .proxy(ProxySelector.of(new InetSocketAddress("myproxy.example.com", 8080)))
                    .build();

            HttpRequest request = HttpRequest.newBuilder()
                    .uri(URI.create("https://www.example.com/"))
                    .GET()
                    .build();

            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
            System.out.println(response.statusCode());
            System.out.println(response.body());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

当初，您曾经理解了Java的HttpClient的基本概念和用法。实际上，还有许多其余性能和配置能够摸索。在理论我的项目中，您可能须要依据具体需要调整HttpClient的配置。心愿这些示例能帮忙您更好地了解Java网络编程中的HttpClient组件。
举荐浏览：

https://mp.weixin.qq.com/s/dV2JzXfgjDdCmWRmE0glDA

https://mp.weixin.qq.com/s/an83QZOWXHqll3SGPYTL5g