android - JSON 文件未下载，函数返回 null

Question

我正在尝试从 google book API 下载一些 JSON。

我正在使用的 URL 和 API key 似乎有效，因为我可以使用浏览器手动获取它。我调用这个类并使用这个函数向它传递一个可用的 URL。我试过 post 和 get(你可以看到我在哪里提交了另一个。

当我在调试时，我可以看到它开始下载过程，或者它似乎开始了，但它总是返回 null。它似乎应该工作。对可能发生的事情有什么想法吗？一个权限什么的。(已经添加了INTERNET PERMISSION)

public static class JSONFunctions2 {
        public static JSONObject getJSONfromURL(String url){

                /*//initialize*/
            InputStream is = null;
                String result = "";
            JSONObject jArray = null;

            //http post
            try{
                 HttpClient httpclient = new DefaultHttpClient();
                 HttpPost httppost = new HttpPost(url);
                 HttpResponse response = httpclient.execute(httppost);
                 HttpEntity entity = response.getEntity();
                 is = entity.getContent();

                     }catch(Exception e){
                  Log.e("log_tag", "Error in http connection "+e.toString());
                     }

                 //convert response to string
                 try{
                       BufferedReader reader = new BufferedReader(new   InputStreamReader(is,"iso-8859-1"),8);
                   StringBuilder sb = new StringBuilder();
                   String line = null;
                   while ((line = reader.readLine()) != null) {
                      sb.append(line + "\n");
                   }
                   is.close();
                   result=sb.toString();
                   }catch(Exception e){
                      Log.e("log_tag", "Error converting result "+e.toString());
                   }

                   /*DefaultHttpClient client = new DefaultHttpClient();
                   HttpGet getRequest = new HttpGet(url);
                   HttpResponse getResponse;
                   getResponse = client.execute(getRequest);
                   HttpEntity getResponseEntity = getResponse.getEntity();
                   if (getResponseEntity != null) {
                     result= EntityUtils.toString(getResponseEntity);
                    }*/

                    /*//try parse the string to a JSON object*/
                    try{
                            jArray = new JSONObject(result);
                    }catch(JSONException e){
                        Log.e("log_tag", "Error parsing data "+e.toString());
                    }

                    return jArray;
                }
    }

我想这是 logcat(我对此有点陌生，其中一些位于顶部可能是因为我将手机从 wifi 切换到 reg.Phone Data)

11-06 23:02:23.716: ERROR/InputDispatcher(159): channel '4081c258 com.buddy/com.BuddyListActivity (server)' ~ Consumer closed input channel or an error occurred.  events=0x8
11-06 23:02:23.716: ERROR/InputDispatcher(159): channel '4081c258 com.buddy/com.BuddyListActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
11-06 23:03:36.616: ERROR/log_tag(4116): Error in http connection javax.net.ssl.SSLPeerUnverifiedException: No peer certificate
11-06 23:03:36.616: ERROR/log_tag(4116): Error converting result java.lang.NullPointerException
11-06 23:04:04.766: ERROR/log_tag(4116): Error parsing data org.json.JSONException: End of input at character 0 of

Answer 1

我通常这样做，可能对你也有用

HttpResponse response = httpClient.execute(httpPost, localContext);     
serverResponseJSON = EntityUtils.toString(response.getEntity());
Log.i("Server Response", serverResponseJSON);