要在Android客户端中进行HTTP请求，可以使用Android提供的HttpClient或HttpURLConnection类。

使用HttpClient进行HTTP请求的示例代码如下：

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;

public class HttpClientExample {
    public static void main(String[] args) {
        HttpClient httpClient = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet("http://example.com/api/data");
        
        try {
            HttpResponse response = httpClient.execute(httpGet);
            String responseBody = EntityUtils.toString(response.getEntity());
            
            // 处理返回的响应数据
            System.out.println(responseBody);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

使用HttpURLConnection进行HTTP请求的示例代码如下：

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

public class HttpURLConnectionExample {
    public static void main(String[] args) {
        try {
            URL url = new URL("http://example.com/api/data");
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            
            BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            StringBuilder response = new StringBuilder();
            String line;
            
            while ((line = reader.readLine()) != null) {
                response.append(line);
            }
            reader.close();
            
            // 处理返回的响应数据
            System.out.println(response.toString());
            
            connection.disconnect();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

这些示例代码演示了如何通过GET请求获取指定URL的响应数据。根据实际需求，可能需要进行POST请求、添加请求头、处理响应状态码等操作，可以根据需要进行相应的修改和扩展。