Ich bin neu in Android und Web Services Programmierung mit Java und ich habe Probleme beim Verbinden meiner Android App mit meinem Java Web Service. Ich habe den Webdienst auf Tomcat bereitgestellt und es verbindet sich mit meinem Telefonbrowser, aber der HttpClient gibt jedes Mal null zurück, wenn ich versuche, eine Verbindung von meiner Android App herzustellen.RESTful Web Service JSON Antworten geben null in Java zurück
Hier ist mein Quellcode.
public class ServiceHandler {
static String response = null;
public final static int GET = 1;
public final static int POST = 2;
public ServiceHandler() {
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* */
public String makeServiceCall(String url, int method) {
return this.makeServiceCall(url, method, null);
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* @params - http request params
* */
public String makeServiceCall(String url, int method, List<NameValuePair> params) {
try {
// http client
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpEntity httpEntity = null;
HttpResponse httpResponse = null;
// Checking http request method type
if (method == POST) {
HttpPost httpPost = new HttpPost(url);
// adding post params
if (params != null) {
httpPost.setEntity(new UrlEncodedFormEntity(params));
}
httpResponse = httpClient.execute(httpPost);
} else if (method == GET) {
// appending params to url
if (params != null) {
String paramString = URLEncodedUtils
.format(params, "utf-8");
url += "?" + paramString;
}
HttpGet httpGet = new HttpGet(url);
httpResponse = httpClient.execute(httpGet);
}
httpEntity = httpResponse.getEntity();
response = EntityUtils.toString(httpEntity);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return response;
}
}
private class Authenticate extends AsyncTask<Void, Void, Void>{
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(LoginActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
String url = "http://192.168.34.1:8080/SchoolWebService/rest/User/"+username+","+password;
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject c = new JSONObject(jsonStr);
String uname = c.getString("username");
String pword = c.getString("password");
snackbar.setText("Authenticated").show();
} catch (JSONException e) {
e.printStackTrace();
}
} else {
snackbar.setText("Authentication Failed!").show();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
}
}
Die Log.d (....); Anweisung gibt immer null zurück.
neben der Verwendung AsyncTask Volley verwenden JSON-Daten zu analysieren ... – Manish
Ich habe keine Ahnung, wie man um das zu tun – Charles
Was mache ich falsch aus meinem Code? – Charles