android parse json,Android parse json from url and store it

Since an http request is time consuming, using an async task will be the best idea. Otherwise the main thread may throw errors. The class shown below can do the download asynchronously

private class jsonLoad extends AsyncTask {

@Override

protected String doInBackground(String... urls) {

String response = "";

for (String url : urls) {

DefaultHttpClient client = new DefaultHttpClient();

HttpGet httpGet = new HttpGet(url);

try {

HttpResponse execute = client.execute(httpGet);

InputStream content = execute.getEntity().getContent();

BufferedReader buffer = new BufferedReader(new InputStreamReader(content));

String s = "";

while ((s = buffer.readLine()) != null) {

response += s;

}

} catch (Exception e) {

e.printStackTrace();

}

}

return response;

}

@Override

protected void onPostExecute(String result) {

// Instantiate a JSON object from the request response

try {

JSONObject jsonObject = new JSONObject(result);

} catch (JSONException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

File file = new File(getApplicationContext().getFilesDir(),"nowList.cache");

try {

file.createNewFile();

FileOutputStream writer = openFileOutput(file.getName(), Context.MODE_PRIVATE);

writer.write(result);

writer.flush();

writer.close();

}

catch (IOException e) { e.printStackTrace(); return false; }

}

}

Unlike the other answer, here the downloaded json string itself is saved in file. So Serialization is not necessary

Now loading the json from url can be done by calling

jsonLoad jtask=new jsonLoad ();

jtask.doInBackground("http:www.json.com/urJsonFile.json");

this will save the contents to the file.

To open the saved json string

File file = new File(getApplicationContext().getFilesDir(),"nowList.cache");

StringBuilder text = new StringBuilder();

try {

BufferedReader br = new BufferedReader(new FileReader(file));

String line;

while ((line = br.readLine()) != null) {

text.append(line);

text.append('\n');

}

br.close();

}

catch (IOException e) {

//print log

}

JSONObject jsonObject = new JSONObject(text);