java http get请求

Java中发送HTTP GET请求可以使用HttpURLConnection或HttpClient两种方式。

1. 使用HttpURLConnection发送GET请求：

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

public class HttpGetExample {
    public static void main(String[] args) throws IOException {
        String url = "http://www.example.com/api/getData";
        URL obj = new URL(url);
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();
        con.setRequestMethod("GET");
        int responseCode = con.getResponseCode();
        System.out.println("Response Code : " + responseCode);
        BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();
        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();
        System.out.println("Response Body : " + response.toString());
    }
}

2. 使用HttpClient发送GET请求：

import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import java.io.IOException;

public class HttpGetExample {
    public static void main(String[] args) throws IOException {
        String url = "http://www.example.com/api/getData";
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet(url);
        httpGet.addHeader("User-Agent", "Mozilla/5.0");
        httpGet.addHeader("Accept-Language", "en-US,en;q=0.5");
        httpGet.addHeader("Accept-Encoding", "gzip, deflate");
        httpGet.addHeader("Connection", "keep-alive");
        httpGet.addHeader("Content-Type", "application/json");
        String responseBody = httpClient.execute(httpGet, response -> {
            int status = response.getStatusLine().getStatusCode();
            if (status >= 200 && status < 300) {
                return EntityUtils.toString(response.getEntity());
            } else {
                throw new IOException("Unexpected response status: " + status);
            }
        });
        System.out.println("Response Body : " + responseBody);
        httpClient.close();
    }
}