java如何发送get请求获取数据(附代码)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class GetRequestUsingHttpURLConnection {
    public static void main(String[] args) {
        String url = "https://api.example.com/data"; // 替换成实际的API地址

        try {
            URL apiUrl = new URL(url);
            HttpURLConnection connection = (HttpURLConnection) apiUrl.openConnection();
            connection.setRequestMethod("GET");

            int responseCode = connection.getResponseCode();
            if (responseCode == HttpURLConnection.HTTP_OK) {
                BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                String inputLine;
                StringBuffer response = new StringBuffer();

                while ((inputLine = reader.readLine()) != null) {
                    response.append(inputLine);
                }
                reader.close();

                System.out.println(response.toString());
            } else {
                System.out.println("GET request failed. Response code: " + responseCode);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>4.9.1</version>
</dependency>

import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

import java.io.IOException;

public class GetRequestUsingOkHttp {
    public static void main(String[] args) {
        String url = "https://api.example.com/data"; // 替换成实际的API地址

        OkHttpClient httpClient = new OkHttpClient();

        Request request = new Request.Builder()
                .url(url)
                .get()
                .build();

        try {
            Response response = httpClient.newCall(request).execute();
            if (response.isSuccessful()) {
                String responseData = response.body().string();
                System.out.println(responseData);
            } else {
                System.out.println("GET request failed. Response code: " + response.code());
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGetWithEntity;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;

import java.io.IOException;

public class Main {
    public static void main(String\[\] args) {
        HttpClient httpClient = HttpClientBuilder.create().build();
        String url = "http://example.com/api";
        String json = "{\"key\":\"value\"}";

        try {
            HttpGetWithEntity httpGet = new HttpGetWithEntity(url);
            httpGet.setEntity(new StringEntity(json));

            HttpResponse response = httpClient.execute(httpGet);
            String responseBody = EntityUtils.toString(response.getEntity());

            System.out.println(responseBody);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}