Json对象对给定键返回null
我正在尝试从字符串中读取JSON（从Web获取），但它返回null 。
具体来说， result.append(name + id); 给我nullnull
JSONParser parser = new JSONParser(); try { Object obj = parser.parse(datJ); JSONObject jsonObject = (JSONObject) obj; String name = (String) jsonObject.get("name"); Integer id = (Integer) jsonObject.get("id"); result.append(name + id); } catch (MalformedURLException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } catch (IOException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } catch (org.json.simple.parser.ParseException e1) { // TODO Auto-generated catch block e1.printStackTrace(); }
考虑到datJ包含以下JSON字符串：
{ "rikeard":{ "id":2828822, "name":"Rikeard", "profileIconId":688, "summonerLevel":30, "revisionDate":1422917445000 } }
编辑：最终代码工作
JSONParser parser = new JSONParser(); try { String datJ = IOUtils.toString(new URL(url)); Object obj = parser.parse(datJ); JSONObject rikeardObject = (JSONObject) ((Map) obj).get("rikeard"); String name = (String) rikeardObject.get("name"); Long id = (Long) rikeardObject.get("id");
特别感谢Sufian和Ved！
“id”和“name”在JSON对象内部，对着“rikeard”键。 所以你需要进行如下更改：
JSONParser parser = new JSONParser(); try { Object obj = parser.parse(datJ); JSONObject jsonObject = (JSONObject) obj; JSONObject rikeardObject = (JSONObject) obj.get("rikeard"); String name = (String) rikeardObject.get("name"); Integer id = (Integer) rikeardObject.get("id"); result.append(name + id); } catch (MalformedURLException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } catch (IOException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } catch (org.json.simple.parser.ParseException e1) { // TODO Auto-generated catch block e1.printStackTrace(); }
使用这种方法对我有用，
private void extractJson(){ String jsonString="{\"rikeard\":{\"id\":2828822,\"name\":\"Rikeard\",\"profileIconId\":688,\"summonerLevel\":30,\"revisionDate\":1422917445000}}"; try { JSONObject jsonObject=new JSONObject(jsonString); if(jsonObject!=null){ jsonObject=jsonObject.optJSONObject("rikeard"); if(jsonObject!=null){ String id=jsonObject.optString("id"); Log.d("MainActivity","id="+id); } } } catch (JSONException e) { e.printStackTrace(); } }
尝试这个：
JSONParser parser = new JSONParser(); try { Object obj = parser.parse(datJ); JSONObject jsonObject = (JSONObject) obj; JSONObject rikeardObject = (JSONObject) jsonObject.get("rikeard");; String name = (String) rikeardObject .get("name"); Integer id = (Integer) rikeardObject .get("id"); result.append(name + id); } catch (MalformedURLException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } catch (IOException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } catch (org.json.simple.parser.ParseException e1) { // TODO Auto-generated catch block e1.printStackTrace(); }