用java发送一个http请求，这个问题

可以使用Java中的URLConnection或HttpClient来发送HTTP请求。

使用URLConnection发送HTTP请求的示例代码：

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

public class HttpUrlConnectionExample {

    public static void main(String[] args) throws Exception {

        String url = "http://example.com";
        URL obj = new URL(url);
        HttpURLConnection con = (HttpURLConnection) obj.openConnection();

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

        // 发送请求
        int responseCode = con.getResponseCode();
        System.out.println("Response Code : " + responseCode);

        // 读取响应内容
        BufferedReader in = new BufferedReader(
                new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer response = new StringBuffer();
        while ((inputLine = in.readLine()) != null) {
            response.append(inputLine);
        }
        in.close();

        // 打印响应内容
        System.out.println(response.toString());
    }
}

使用HttpClient发送HTTP请求的示例代码：

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClientBuilder;
import java.io.BufferedReader;
import java.io.InputStreamReader;

public class HttpClientExample {

    public static void main(String[] args) throws Exception {

        String url = "http://example.com";
        HttpClient client = HttpClientBuilder.create().build();
        HttpGet request = new HttpGet(url);

        // 发送请求
        HttpResponse response = client.execute(request);
        System.out.println("Response Code : " + response.getStatusLine().getStatusCode());

        // 读取响应内容
        BufferedReader rd = new BufferedReader(
                new InputStreamReader(response.getEntity().getContent()));
        StringBuffer result = new StringBuffer();
        String line = "";
        while ((line = rd.readLine()) != null) {
            result.append(line);
        }

        // 打印响应内容
        System.out.println(result.toString());
    }
}