使用Java发送POST请求的四种方式

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 PostRequestExample {
    public static void main(String[] args) {
        try {
            // 请求URL
            String url = "https://example.com/api";
            
            // 创建连接
            URL obj = new URL(url);
            HttpURLConnection con = (HttpURLConnection) obj.openConnection();
            
            // 设置请求方法
            con.setRequestMethod("POST");
            
            // 设置请求头
            con.setRequestProperty("Content-Type", "application/json");
            con.setRequestProperty("Accept", "application/json");
            
            // 请求体数据
            String requestBody = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
            
            // 启用输出流
            con.setDoOutput(true);
            
            // 发送请求体
            try(OutputStream os = con.getOutputStream()) {
                byte[] input = requestBody.getBytes(StandardCharsets.UTF_8);
                os.write(input, 0, input.length);
            }
            
            // 获取响应码
            int responseCode = con.getResponseCode();
            System.out.println("Response Code: " + responseCode);
            
            // 读取响应
            try(BufferedReader br = new BufferedReader(
                new InputStreamReader(con.getInputStream(), StandardCharsets.UTF_8))) {
                StringBuilder response = new StringBuilder();
                String responseLine;
                while ((responseLine = br.readLine()) != null) {
                    response.append(responseLine.trim());
                }
                System.out.println("Response: " + response.toString());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version>
</dependency>

代码示例：

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
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 HttpClientPostExample {
    public static void main(String[] args) {
        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
            // 创建POST请求
            HttpPost httpPost = new HttpPost("https://example.com/api");
            
            // 设置请求头
            httpPost.setHeader("Content-Type", "application/json");
            httpPost.setHeader("Accept", "application/json");
            
            // 设置请求体
            String requestBody = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
            httpPost.setEntity(new StringEntity(requestBody));
            
            // 执行请求
            try (CloseableHttpResponse response = httpClient.execute(httpPost)) {
                // 获取响应码
                int statusCode = response.getStatusLine().getStatusCode();
                System.out.println("Response Code: " + statusCode);
                
                // 获取响应体
                HttpEntity entity = response.getEntity();
                if (entity != null) {
                    String result = EntityUtils.toString(entity);
                    System.out.println("Response: " + result);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
    <version>2.5.0</version>
</dependency>

代码示例：

import org.springframework.http.*;
import org.springframework.web.client.RestTemplate;

public class RestTemplatePostExample {
    public static void main(String[] args) {
        // 创建RestTemplate实例
        RestTemplate restTemplate = new RestTemplate();
        
        // 请求URL
        String url = "https://example.com/api";
        
        // 设置请求头
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_JSON);
        headers.setAccept(Collections.singletonList(MediaType.APPLICATION_JSON));
        
        // 请求体数据
        String requestBody = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
        
        // 创建请求实体
        HttpEntity<String> requestEntity = new HttpEntity<>(requestBody, headers);
        
        // 发送POST请求
        ResponseEntity<String> response = restTemplate.postForEntity(url, requestEntity, String.class);
        
        // 获取响应信息
        System.out.println("Response Code: " + response.getStatusCodeValue());
        System.out.println("Response Body: " + response.getBody());
    }
}

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 Java11HttpClientExample {
    public static void main(String[] args) {
        // 创建HttpClient
        HttpClient httpClient = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_1_1)
                .connectTimeout(Duration.ofSeconds(10))
                .build();
        
        // 请求体
        String requestBody = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
        
        // 创建HttpRequest
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://example.com/api"))
                .header("Content-Type", "application/json")
                .header("Accept", "application/json")
                .POST(HttpRequest.BodyPublishers.ofString(requestBody))
                .build();
        
        try {
            // 发送请求
            HttpResponse<String> response = httpClient.send(
                    request, HttpResponse.BodyHandlers.ofString());
            
            // 输出结果
            System.out.println("Status Code: " + response.statusCode());
            System.out.println("Response Body: " + response.body());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}