请用java写一个 http请求

以下是一个使用Java进行HTTP请求的示例代码：

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

public class HttpExample {

    public static void main(String[] args) throws Exception {
        String url = "https://www.example.com/api/data";
        URL obj = new URL(url);
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();

        // 设置请求方法
        con.setRequestMethod("GET");

        // 添加请求头
        con.setRequestProperty("User-Agent", "Mozilla/5.0");

        int responseCode = con.getResponseCode();
        System.out.println("发送的请求URL：" + url);
        System.out.println("响应代码：" + 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();

        // 输出响应结果
        System.out.println(response.toString());
    }
}

该示例代码使用Java的HttpURLConnection类发送HTTP GET请求，并输出响应结果。您可以根据需要修改请求方法和请求头信息。