IT技术社区_专业开发者平台_最新编程教程与解决方案 -沐辰社区

Java案例如何实现网络请求？

wen python案例 195

本文目录导读：

Java案例如何实现网络请求？

  1. 使用 HttpURLConnection（原生方式）
  2. 使用 Apache HttpClient
  3. 使用 OkHttp
  4. 使用 Spring RestTemplate（Spring 框架）
  5. 使用 Java 11+ HttpClient（内置）
  6. 总结与建议

在Java中实现网络请求有多种方式,以下是最常用的几种方法及完整示例。

使用 HttpURLConnection（原生方式）

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.StandardCharsets;
public class HttpURLConnectionExample {
    // GET请求
    public static String sendGet(String urlStr) throws Exception {
        URL url = new URL(urlStr);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        // 设置请求方法
        connection.setRequestMethod("GET");
        connection.setRequestProperty("Content-Type", "application/json");
        connection.setConnectTimeout(5000);
        connection.setReadTimeout(5000);
        // 获取响应码
        int responseCode = connection.getResponseCode();
        System.out.println("响应码: " + responseCode);
        // 读取响应
        BufferedReader reader = new BufferedReader(
            new InputStreamReader(connection.getInputStream(), StandardCharsets.UTF_8));
        StringBuilder response = new StringBuilder();
        String line;
        while ((line = reader.readLine()) != null) {
            response.append(line);
        }
        reader.close();
        return response.toString();
    }
    // POST请求
    public static String sendPost(String urlStr, String jsonBody) throws Exception {
        URL url = new URL(urlStr);
        HttpURLConnection connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("POST");
        connection.setRequestProperty("Content-Type", "application/json");
        connection.setDoOutput(true);
        connection.setConnectTimeout(5000);
        connection.setReadTimeout(5000);
        // 写入请求体
        try (OutputStream os = connection.getOutputStream()) {
            byte[] input = jsonBody.getBytes(StandardCharsets.UTF_8);
            os.write(input, 0, input.length);
        }
        // 获取响应
        int responseCode = connection.getResponseCode();
        BufferedReader reader = new BufferedReader(
            new InputStreamReader(connection.getInputStream(), StandardCharsets.UTF_8));
        StringBuilder response = new StringBuilder();
        String line;
        while ((line = reader.readLine()) != null) {
            response.append(line);
        }
        reader.close();
        return response.toString();
    }
    public static void main(String[] args) {
        try {
            // GET请求示例
            String getResponse = sendGet("http://jsonplaceholder.typicode.com/posts/1");
            System.out.println("GET响应: " + getResponse);
            // POST请求示例
            String jsonBody = "{\"title\": \"foo\", \"body\": \"bar\", \"userId\": 1}";
            String postResponse = sendPost("http://jsonplaceholder.typicode.com/posts", jsonBody);
            System.out.println("POST响应: " + postResponse);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

使用 Apache HttpClient

首先添加 Maven 依赖：

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.14</version>
</dependency>
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
public class HttpClientExample {
    // GET请求
    public static String sendGet(String url) throws Exception {
        try (CloseableHttpClient client = HttpClients.createDefault()) {
            HttpGet request = new HttpGet(url);
            request.setHeader("Content-Type", "application/json");
            HttpResponse response = client.execute(request);
            int statusCode = response.getStatusLine().getStatusCode();
            System.out.println("响应码: " + statusCode);
            return EntityUtils.toString(response.getEntity());
        }
    }
    // POST请求
    public static String sendPost(String url, String jsonBody) throws Exception {
        try (CloseableHttpClient client = HttpClients.createDefault()) {
            HttpPost request = new HttpPost(url);
            request.setHeader("Content-Type", "application/json");
            request.setEntity(new StringEntity(jsonBody, "UTF-8"));
            HttpResponse response = client.execute(request);
            return EntityUtils.toString(response.getEntity());
        }
    }
    public static void main(String[] args) {
        try {
            String response = sendGet("http://jsonplaceholder.typicode.com/posts/1");
            System.out.println("响应: " + response);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

使用 OkHttp

添加 Maven 依赖：

<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>4.12.0</version>
</dependency>
import okhttp3.*;
import java.io.IOException;
public class OkHttpExample {
    private static final OkHttpClient client = new OkHttpClient();
    // GET请求
    public static String sendGet(String url) throws IOException {
        Request request = new Request.Builder()
                .url(url)
                .addHeader("Content-Type", "application/json")
                .build();
        try (Response response = client.newCall(request).execute()) {
            if (!response.isSuccessful()) {
                throw new IOException("请求失败: " + response.code());
            }
            return response.body().string();
        }
    }
    // POST请求
    public static String sendPost(String url, String jsonBody) throws IOException {
        MediaType JSON = MediaType.get("application/json; charset=utf-8");
        RequestBody body = RequestBody.create(jsonBody, JSON);
        Request request = new Request.Builder()
                .url(url)
                .post(body)
                .build();
        try (Response response = client.newCall(request).execute()) {
            return response.body().string();
        }
    }
    // 异步请求
    public static void sendAsyncGet(String url) {
        Request request = new Request.Builder()
                .url(url)
                .build();
        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                e.printStackTrace();
            }
            @Override
            public void onResponse(Call call, Response response) throws IOException {
                System.out.println("异步响应: " + response.body().string());
            }
        });
    }
    public static void main(String[] args) {
        try {
            String response = sendGet("http://jsonplaceholder.typicode.com/posts/1");
            System.out.println("响应: " + response);
            // 异步请求
            sendAsyncGet("http://jsonplaceholder.typicode.com/posts/1");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

使用 Spring RestTemplate（Spring 框架）

添加 Maven 依赖：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
import org.springframework.http.*;
import org.springframework.web.client.RestTemplate;
public class RestTemplateExample {
    public static String sendGet(String url) {
        RestTemplate restTemplate = new RestTemplate();
        ResponseEntity<String> response = restTemplate.getForEntity(url, String.class);
        return response.getBody();
    }
    public static String sendPost(String url, String jsonBody) {
        RestTemplate restTemplate = new RestTemplate();
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        HttpEntity<String> request = new HttpEntity<>(jsonBody, headers);
        ResponseEntity<String> response = restTemplate.postForEntity(url, request, String.class);
        return response.getBody();
    }
    public static void main(String[] args) {
        String response = sendGet("http://jsonplaceholder.typicode.com/posts/1");
        System.out.println("响应: " + response);
    }
}

使用 Java 11+ HttpClient（内置）

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 JavaHttpClientExample {
    private static final HttpClient client = HttpClient.newBuilder()
            .connectTimeout(Duration.ofSeconds(5))
            .build();
    // GET请求
    public static String sendGet(String url) throws Exception {
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(url))
                .header("Content-Type", "application/json")
                .timeout(Duration.ofSeconds(5))
                .GET()
                .build();
        HttpResponse<String> response = client.send(request, 
            HttpResponse.BodyHandlers.ofString());
        return response.body();
    }
    // POST请求
    public static String sendPost(String url, String jsonBody) throws Exception {
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create(url))
                .header("Content-Type", "application/json")
                .timeout(Duration.ofSeconds(5))
                .POST(HttpRequest.BodyPublishers.ofString(jsonBody))
                .build();
        HttpResponse<String> response = client.send(request, 
            HttpResponse.BodyHandlers.ofString());
        return response.body();
    }
    public static void main(String[] args) {
        try {
            String response = sendGet("http://jsonplaceholder.typicode.com/posts/1");
            System.out.println("响应: " + response);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

总结与建议

方式 优点 缺点 适用场景
HttpURLConnection 无需第三方依赖 API较原始，代码量多 简单请求
Apache HttpClient 功能完善，稳定性高 需要引入依赖 企业级应用
OkHttp 性能优秀，支持HTTP/2 需要引入依赖 移动端/高性能场景
Spring RestTemplate 与Spring集成好 依赖Spring框架 Spring项目
Java HttpClient(11+) 内置，API现代化 仅支持Java11+ Java11+项目

建议：

  • 如果使用Spring Boot，优先选择 RestTemplate 或 WebClient
  • 新项目推荐使用 OkHttp 或 Java 11+ HttpClient
  • 简单的测试场景可以使用 HttpURLConnection

版权声明：NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 NBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 CBA直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 足球直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播 英超直播

上一篇Java案例如何实现爬虫？

下一篇Java案例如何实现语音识别？

相关文章

抱歉，评论功能暂时关闭!

友情链接攻略窝 · 礼包窝 · 配置窝 · 换算窝 · 算法窝 · 查文窝 · 手册窝 · 问答窝 · 全文搜 · 手册库
相关站点礼包窝 · 查文窝