Java 截击服务器关闭错误

我想知道当我做一个请求时，服务器是否关闭了，基本上我正在尝试做一个简单的注册（它已经工作了），但是如果在我点击注册时放下nodeJS服务器，我的toast上不会出现任何错误，我试着按照我找到的一些答案进行操作，但没有任何效果

以下是我尝试过的：

 public void notifyError(String requestType,VolleyError error) {
                String body;
                if(error.networkResponse.data!=null) {
                    String statusCode = String.valueOf(error.networkResponse.statusCode);
                    try {
                        if (error instanceof NetworkError) {
                            Log.d("internet","nao tem internet ligada");
                        }
                        else if (error instanceof ServerError) {
                            Log.d("internet","The server could not be found. Please try again after some time!!");
                        }
                        body = new String(error.networkResponse.data,"UTF-8");
                        JSONObject jsonObj = new JSONObject(body);
                        Log.d("body",String.valueOf(jsonObj.get("message")));
                        showToast(String.valueOf(jsonObj.get("message")));
                    } catch (UnsupportedEncodingException e) {
                        showToast("You need to connect to the internet!");
                    } catch (JSONException e) {
                        Log.d("json:","problems decoding jsonObj");
                    }
                }

对于与我如何构建截击示例相关的任何问题，我都遵循以下步骤

网络错误和服务器错误中的消息从未显示，任何提示？

删除“如果”条件，error.networkResponse.data return null

public void notifyError(String requestType,VolleyError error) {
    String body;
    String statusCode = String.valueOf(error.networkResponse.statusCode);
    try {
        if (error instanceof NetworkError) {
            Log.d("internet","nao tem internet ligada");
        } else if (error instanceof ServerError) {
            Log.d("internet","The server could not be found. Please try again after some time!!");
        }

        body = new String(String.valueOf(error.networkResponse.statusCode),"UTF-8"); 
        JSONObject jsonObj = new JSONObject(body);
        Log.d("body",String.valueOf(jsonObj.get("message")));
        showToast(String.valueOf(jsonObj.get("message")));
    } catch (UnsupportedEncodingException e) {
        showToast("You need to connect to the internet!");
    } catch (JSONException e) {
        Log.d("json:","problems decoding jsonObj");
    }
}

---

您的意思是if（error instanceof NetworkError）{Log.d（“internet”，“nao tem internet ligada”）；}或者if（error instanceof ServerError）{Log.d（“internet”，“找不到服务器。请稍后重试！！”）；}如果（error.networkResponse.data！=null），请从代码中跳过这一行请检查状态并打印字符串statusCode=String.valueOf（error.networkResponse.statusCode）；Log.e（“Error”，_Log:Error:“+Error.toString（）+”+Error.networkResponse.statusCode）；