我有以下 JSON 解析器的代码。其实不是我自己写的，是从各种stackoverflow问题中收集的。但不知何故，它不起作用。我允许使用互联网：
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
String url=null;
// constructor
public JSONParser() {
}
// function get JSON from URL
public JSONObject makeHttpRequest(String url) {
BackGroundTask Task= new BackGroundTask(url);
try {
return Task.execute().get();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}
}
public class BackGroundTask extends AsyncTask<String, String, JSONObject>{
String URL=null;
public BackGroundTask(String url) {
URL = url;
}
@Override
protected JSONObject doInBackground(String... params) {
// TODO Auto-generated method stub
// Making HTTP request
try {
// Making HTTP request
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
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();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
}
编辑：
您能看到任何可能导致此类失败的问题部分吗？我调试了我的代码，发现在这行之后
JSONParser jParser = new JSONParser();
JSONObject json = jParser.makeHttpRequest(URL);
json对象是null。