import org.json.JSONArray;
import org.json.JSONObject;

public class Main {
  public static void main(String[] args) {
    String data = "[{\"name\":\"03水泥销售合同范本.docx\",\"url\":\"/storage_area/d19e84640fb74ce9af97d1cbe226ca8e.docx\"}]";
    
    JSONArray jsonArray = new JSONArray(data);
    JSONObject jsonObject = jsonArray.getJSONObject(0);
    
    String downloadUrl = jsonObject.getString("url");
    
    System.out.println(downloadUrl);
  }
}