Java开发中请求头的概念与写法代码示例

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
public class HttpURLConnectionExample {
    public static void main(String[] args) throws IOException {
        // 创建 URL 对象
        URL url = new URL("https://example.com");
        // 打开连接
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        // 设置请求方法为 GET
        connection.setRequestMethod("GET");
        // 添加请求头
        connection.setRequestProperty("User-Agent", "Mozilla/5.0");
        connection.setRequestProperty("Accept", "application/json");
        // 获取响应状态码
        int responseCode = connection.getResponseCode();
        System.out.println("Response Code: " + responseCode);
        // 读取响应内容
        BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
        String line;
        StringBuilder response = new StringBuilder();
        while ((line = reader.readLine()) != null) {
            response.append(line);
        }
        reader.close();
        // 输出响应内容
        System.out.println("Response Body: " + response.toString());
        // 关闭连接
        connection.disconnect();
    }
}

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
public class HttpClientExample {
    public static void main(String[] args) throws IOException, InterruptedException {
        // 创建 HttpClient 实例
        HttpClient client = HttpClient.newHttpClient();
        // 创建 HttpRequest 并添加请求头
        HttpRequest request = HttpRequest.newBuilder()
               .uri(URI.create("https://example.com"))
               .header("Content-Type", "application/json")
               .header("Authorization", "Bearer your_token")
               .POST(HttpRequest.BodyPublishers.ofString("{\"key\": \"value\"}"))
               .build();
        // 发送请求并获取响应
        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
        // 输出响应状态码和内容
        System.out.println("Response Code: " + response.statusCode());
        System.out.println("Response Body: " + response.body());
    }
}

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import java.io.IOException;
public class ApacheHttpClientExample {
    public static void main(String[] args) throws IOException {
        // 创建 HttpClient 实例
        HttpClient client = HttpClients.createDefault();
        // 创建 HttpGet 请求
        HttpGet request = new HttpGet("https://example.com");
        // 添加请求头
        request.addHeader("User-Agent", "MyApp/1.0");
        request.addHeader("Accept", "text/html");
        // 执行请求
        HttpResponse response = client.execute(request);
        // 输出响应状态码和内容
        System.out.println("Response Code: " + response.getStatusLine().getStatusCode());
        System.out.println("Response Body: " + EntityUtils.toString(response.getEntity()));
    }
}