I have written a REST web service in Netbean IDE using Jersey Framework and Java.
For every request the user needs to provide a username and a password, I know that this authentication is not a best practice (using a curl command like: curl -u username:password -X PUT http://localhsot:8080/user).
Now I want to call a REST web service from an Android Class.
How should I do it?
I have an Android Class which uses DefaultHttpClient and CredentialUsernameAndPassword, but when I run it in Eclipse, sometimes I get a runtime exception or SDK exception.
This question is related to
java
android
web-services
rest
authorization
What back-end? If JAVA then you can use REST with Java (JAX-RS) using Jersey.
On the Android side you can use this simple RestClient to work with that REST service.
For JSON <--> Object mapping on both sides (Android, Java back-end) you can use GSON.
This is an sample restclient class
public class RestClient
{
public enum RequestMethod
{
GET,
POST
}
public int responseCode=0;
public String message;
public String response;
public void Execute(RequestMethod method,String url,ArrayList<NameValuePair> headers,ArrayList<NameValuePair> params) throws Exception
{
switch (method)
{
case GET:
{
// add parameters
String combinedParams = "";
if (params!=null)
{
combinedParams += "?";
for (NameValuePair p : params)
{
String paramString = p.getName() + "=" + URLEncoder.encode(p.getValue(),"UTF-8");
if (combinedParams.length() > 1)
combinedParams += "&" + paramString;
else
combinedParams += paramString;
}
}
HttpGet request = new HttpGet(url + combinedParams);
// add headers
if (headers!=null)
{
headers=addCommonHeaderField(headers);
for (NameValuePair h : headers)
request.addHeader(h.getName(), h.getValue());
}
executeRequest(request, url);
break;
}
case POST:
{
HttpPost request = new HttpPost(url);
// add headers
if (headers!=null)
{
headers=addCommonHeaderField(headers);
for (NameValuePair h : headers)
request.addHeader(h.getName(), h.getValue());
}
if (params!=null)
request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
executeRequest(request, url);
break;
}
}
}
private ArrayList<NameValuePair> addCommonHeaderField(ArrayList<NameValuePair> _header)
{
_header.add(new BasicNameValuePair("Content-Type","application/x-www-form-urlencoded"));
return _header;
}
private void executeRequest(HttpUriRequest request, String url)
{
HttpClient client = new DefaultHttpClient();
HttpResponse httpResponse;
try
{
httpResponse = client.execute(request);
responseCode = httpResponse.getStatusLine().getStatusCode();
message = httpResponse.getStatusLine().getReasonPhrase();
HttpEntity entity = httpResponse.getEntity();
if (entity != null)
{
InputStream instream = entity.getContent();
response = convertStreamToString(instream);
instream.close();
}
}
catch (Exception e)
{ }
}
private static String convertStreamToString(InputStream is)
{
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try
{
while ((line = reader.readLine()) != null)
{
sb.append(line + "\n");
}
is.close();
}
catch (IOException e)
{ }
return sb.toString();
}
}
I used OkHttpClient to call restful web service. It's very simple.
OkHttpClient httpClient = new OkHttpClient();
Request request = new Request.Builder()
.url(url)
.build();
Response response = httpClient.newCall(request).execute();
String body = response.body().string()
Using Spring for Android with RestTemplate https://spring.io/guides/gs/consuming-rest-android/
// The connection URL
String url = "https://ajax.googleapis.com/ajax/" +
"services/search/web?v=1.0&q={query}";
// Create a new RestTemplate instance
RestTemplate restTemplate = new RestTemplate();
// Add the String message converter
restTemplate.getMessageConverters().add(new StringHttpMessageConverter());
// Make the HTTP GET request, marshaling the response to a String
String result = restTemplate.getForObject(url, String.class, "Android");
Stop with whatever you were doing ! :)
Implement the RESTful client as a SERVICE and delegate the intensive network stuff to activity independent component: a SERVICE.
Watch this insightful video http://www.youtube.com/watch?v=xHXn3Kg2IQE where Virgil Dobjanschi is explaining his approach(es) to this challenge...
Recently discovered that a third party library - Square Retrofit can do the job very well.
Defining REST endpoint
public interface GitHubService {
@GET("/users/{user}/repos")
List<Repo> listRepos(@Path("user") String user,Callback<List<User>> cb);
}
Getting the concrete service
RestAdapter restAdapter = new RestAdapter.Builder()
.setEndpoint("https://api.github.com")
.build();
GitHubService service = restAdapter.create(GitHubService.class);
Calling the REST endpoint
List<Repo> repos = service.listRepos("octocat",new Callback<List<User>>() {
@Override
public void failure(final RetrofitError error) {
android.util.Log.i("example", "Error, body: " + error.getBody().toString());
}
@Override
public void success(List<User> users, Response response) {
// Do something with the List of Users object returned
// you may populate your adapter here
}
});
The library handles the json serialization and deserailization for you. You may customize the serialization and deserialization too.
Gson gson = new GsonBuilder()
.setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
.registerTypeAdapter(Date.class, new DateTypeAdapter())
.create();
RestAdapter restAdapter = new RestAdapter.Builder()
.setEndpoint("https://api.github.com")
.setConverter(new GsonConverter(gson))
.build();
Follow the below steps to consume RestFul in android.
Step1
Create a android blank project.
Step2
Need internet access permission. write the below code in AndroidManifest.xml file.
<uses-permission android:name="android.permission.INTERNET">
</uses-permission>
Step3
Need RestFul url which is running in another server or same machine.
Step4
Make a RestFul Client which will extends AsyncTask. See RestFulPost.java.
Step5
Make DTO class for RestFull Request and Response.
RestFulPost.java
package javaant.com.consuming_restful.restclient;
import android.app.ProgressDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
import com.google.gson.Gson;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import java.util.Map;
import javaant.com.consuming_restful.util.Util;
/**
* Created by Nirmal Dhara on 29-10-2015.
*/
public class RestFulPost extends AsyncTask<map, void,="" string=""> {
RestFulResult restFulResult = null;
ProgressDialog Asycdialog;
String msg;
String task;
public RestFulPost(RestFulResult restFulResult, Context context, String msg,String task) {
this.restFulResult = restFulResult;
this.task=task;
this.msg = msg;
Asycdialog = new ProgressDialog(context);
}
@Override
protected String doInBackground(Map... params) {
String responseStr = null;
Object dataMap = null;
HttpPost httpost = new HttpPost(params[0].get("url").toString());
try {
dataMap = (Object) params[0].get("data");
Gson gson = new Gson();
Log.d("data map", "data map------" + gson.toJson(dataMap));
httpost.setEntity(new StringEntity(gson.toJson(dataMap)));
httpost.setHeader("Accept", "application/json");
httpost.setHeader("Content-type", "application/json");
DefaultHttpClient httpclient= Util.getClient();
HttpResponse response = httpclient.execute(httpost);
int statusCode = response.getStatusLine().getStatusCode();
Log.d("resonse code", "----------------" + statusCode);
if (statusCode == 200)
responseStr = EntityUtils.toString(response.getEntity());
if (statusCode == 404) {
responseStr = "{\n" +
"\"status\":\"fail\",\n" +
" \"data\":{\n" +
"\"ValidUser\":\"Service not available\",\n" +
"\"code\":\"404\"\n" +
"}\n" +
"}";
}
} catch (Exception e) {
e.printStackTrace();
}
return responseStr;
}
@Override
protected void onPreExecute() {
Asycdialog.setMessage(msg);
//show dialog
Asycdialog.show();
super.onPreExecute();
}
@Override
protected void onPostExecute(String s) {
Asycdialog.dismiss();
restFulResult.onResfulResponse(s,task);
}
}
For more details and complete code please visit http://javaant.com/consume-a-restful-webservice-in-android/#.VwzbipN96Hs
Perhaps am late or maybe you've already used it before but there is another one called ksoap and its pretty amazing.. It also includes timeouts and can parse any SOAP based webservice efficiently. I also made a few changes to suit my parsing.. Look it up
Here is my Library That I have created for simple Webservice Calling,
You can use this by adding a one line gradle dependency -
compile 'com.scantity.ScHttpLibrary:ScHttpLibrary:1.0.0'
Here is the demonstration of using.
Source: Stackoverflow.com