如何在android应用中只从服务器获取更新的数据？

GET /api/updates?last_update_timestamp=1633072800

import android.os.AsyncTask;
import android.util.Log;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class UpdateTask extends AsyncTask<Void, Void, String> {
    private static final String TAG = "UpdateTask";
    private static final String UPDATE_URL = "https://yourserver.com/api/updates";
    private long lastUpdateTimestamp;

    public UpdateTask(long lastUpdateTimestamp) {
        this.lastUpdateTimestamp = lastUpdateTimestamp;
    }

    @Override
    protected String doInBackground(Void... voids) {
        try {
            URL url = new URL(UPDATE_URL + "?last_update_timestamp=" + lastUpdateTimestamp);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            String inputLine;
            StringBuilder content = new StringBuilder();
            while ((inputLine = in.readLine()) != null) {
                content.append(inputLine);
            }
            in.close();
            connection.disconnect();
            return content.toString();
        } catch (Exception e) {
            Log.e(TAG, "Error fetching updates", e);
            return null;
        }
    }

    @Override
    protected void onPostExecute(String result) {
        if (result != null) {
            try {
                JSONArray updates = new JSONArray(result);
                for (int i = 0; i < updates.length(); i++) {
                    JSONObject update = updates.getJSONObject(i);
                    // Process each update
                    Log.d(TAG, "Update: " + update.toString());
                }
                // Update last_update_timestamp
                if (updates.length() > 0) {
                    lastUpdateTimestamp = updates.getJSONObject(updates.length() - 1).getLong("timestamp");
                }
            } catch (JSONException e) {
                Log.e(TAG, "JSON parsing error", e);
            }
        }
    }
}

long lastUpdateTimestamp = getLastUpdateTimestamp(); // 获取上次更新的时间戳
new UpdateTask(lastUpdateTimestamp).execute();