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How-to: Android as a RESTful Client
This is a how-to focused on creating a RESTful java object at Android. I’ve used HTTPClient, HTTPEntry, HTTPGet, HTTPResponse, JSONArray and JSONObject classes. I think it’ll be useful if we need to use a web-service from client application.
I’ve implemented a simple Java Object called RestClient which connects to a given Rest-JSON service. After connection, this object prints response content. Using this content, a JSONObject created. Then, RestClient prints the JSONObject’s content, parses all values of this object and prints them as well. And as a last job, RestClient pushes a sample value to the JSONObject.
I’ve uploaded RestClient. Hope it’ll be useful.
P.s: To get access to internet at Android, following field must be included to AndroidManifest.xml file of the project.
<uses-permission android:name="android.permission.INTERNET"></uses-permission>package praeda.muzikmekan; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.ClientProtocolException; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.DefaultHttpClient; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import android.util.Log; public class RestClient { private static String convertStreamToString(InputStream is) { /* * To convert the InputStream to String we use the BufferedReader.readLine() * method. We iterate until the BufferedReader return null which means * there's no more data to read. Each line will appended to a StringBuilder * and returned as String. */ BufferedReader reader = new BufferedReader(new InputStreamReader(is)); StringBuilder sb = new StringBuilder(); String line = null; try { while ((line = reader.readLine()) != null) { sb.append(line + "\n"); } } catch (IOException e) { e.printStackTrace(); } finally { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } return sb.toString(); } /* This is a test function which will connects to a given * rest service and prints it's response to Android Log with * labels "Praeda". */ public static void connect(String url) { HttpClient httpclient = new DefaultHttpClient(); // Prepare a request object HttpGet httpget = new HttpGet(url); // Execute the request HttpResponse response; try { response = httpclient.execute(httpget); // Examine the response status Log.i("Praeda",response.getStatusLine().toString()); // Get hold of the response entity HttpEntity entity = response.getEntity(); // If the response does not enclose an entity, there is no need // to worry about connection release if (entity != null) { // A Simple JSON Response Read InputStream instream = entity.getContent(); String result= convertStreamToString(instream); Log.i("Praeda",result); // A Simple JSONObject Creation JSONObject json=new JSONObject(result); Log.i("Praeda","<jsonobject>\n"+json.toString()+"\n</jsonobject>"); // A Simple JSONObject Parsing JSONArray nameArray=json.names(); JSONArray valArray=json.toJSONArray(nameArray); for(int i=0;i<valArray.length();i++) { Log.i("Praeda","<jsonname"+i+">\n"+nameArray.getString(i)+"\n</jsonname"+i+">\n" +"<jsonvalue"+i+">\n"+valArray.getString(i)+"\n</jsonvalue"+i+">"); } // A Simple JSONObject Value Pushing json.put("sample key", "sample value"); Log.i("Praeda","<jsonobject>\n"+json.toString()+"\n</jsonobject>"); // Closing the input stream will trigger connection release instream.close(); } } catch (ClientProtocolException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
출처 : http://senior.ceng.metu.edu.tr/2009/praeda/2009/01/11/a-simple-restful-client-at-android/
