在Java中发送HTTP POST请求

import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.StandardCharsets;

public class HttpPostExample {
    public static void main(String[] args) throws Exception {
        String url = "https://example.com/api";
        String data = "key1=value1&key2=value2";

        URL objUrl = new URL(url);
        HttpURLConnection connection = (HttpURLConnection) objUrl.openConnection();

        connection.setRequestMethod("POST");
        connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
        connection.setRequestProperty("Content-Length", Integer.toString(data.getBytes(StandardCharsets.UTF_8).length));

        connection.setDoOutput(true);
        OutputStream outputStream = connection.getOutputStream();
        outputStream.write(data.getBytes(StandardCharsets.UTF_8));
        outputStream.flush();
        outputStream.close();

        int responseCode = connection.getResponseCode();
        System.out.println("Response Code: " + responseCode);

        connection.disconnect();
    }
}

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 HttpPostExample {
    public static void main(String[] args) throws Exception {
        String url = "https://example.com/api";
        String data = "key1=value1&key2=value2";

        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost(url);
        httpPost.setHeader("Content-Type", "application/x-www-form-urlencoded");

        StringEntity stringEntity = new StringEntity(data);
        httpPost.setEntity(stringEntity);

        CloseableHttpResponse response = httpClient.execute(httpPost);
        HttpEntity entity = response.getEntity();
        String responseString = EntityUtils.toString(entity, StandardCharsets.UTF_8);
        EntityUtils.consume(entity);

        System.out.println("Response: " + responseString);
        response.close();
        httpClient.close();
    }
}