I have a webservice that sends a typed arraylist which I capture via HttpResponse like so:
// create GET request
HttpGet httpGet = new HttpGet("http://localhost:8084/MinecraftRestServer/webresources/Items");
// execute GET request
HttpResponse response = client.execute(httpGet);
// check response
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
if (statusCode == 200) { // response OK
// retreive response
List<Recipe> recipesList = new ArrayList<Recipe>();
HttpEntity jsonObj = response.getEntity();
//What's next?
The array that's being sent from the webservice looks like this:
recipesList.add(new Item(1, 11, "diamond_ingot", "Diamond ingot",
"0,0,0,0,0,0,0,0,1", "air,diamond_ore"));
recipesList.add(new Item(2, 11, "iron_ingot", "Iron ingot",
"0,0,0,0,0,0,0,0,1", "air,iron_ore"));
And comes out in this format:
[{"recipeCategory":11,"recipeImageID":"diamond_ingot","recipeDescription":"Diamond ingot","recipeLocations":"0,0,0,0,0,0,0,0,1","usedImages":"air,diamond_ore","recipeID":1},{"recipeCategory":11,"recipeImageID":"iron_ingot","recipeDescription":"Iron ingot","recipeLocations":"0,0,0,0,0,0,0,0,1","usedImages":"air,iron_ore","recipeID":2},{"recipeCategory":11,"recipeImageID":"gold_ingot","recipeDescription":"Gold ingot","recipeLocations":"0,0,0,0,0,0,0,0,1","usedImages":"air,gold_ore","recipeID":3},{"recipeCategory":11,"recipeImageID":"diamond_ore","recipeDescription":"Diamond ore","recipeLocations":"0,0,0,0,0,0,0,0,1","usedImages":"air,wooden_pickaxe","recipeID":4},{"recipeCategory":11,"recipeImageID":"iron_ore","recipeDescription":"Iron ore","recipeLocations":"0,0,0,0,0,0,0,0,1","usedImages":"air,wooden_pickaxe","recipeID":5},{"recipeCategory":11,"recipeImageID":"gold_ore","recipeDescription":"Gold ore","recipeLocations":"0,0,0,0,0,0,0,0,1","usedImages":"air,wooden_pickaxe","recipeID":6},{"recipeCategory":2,"recipeImageID":"diamond_boots","recipeDescription":"Boots (Diamond)","recipeLocations":"0,0,0,1,0,1,1,0,1","usedImages":"air,diamond_ingot","recipeID":7},{"recipeCategory":2,"recipeImageID":"gold_boots","recipeDescription":"Boots (Gold)","recipeLocations":"0,0,0,1,0,1,1,0,1","usedImages":"air,gold_ingot","recipeID":8},{"recipeCategory":2,"recipeImageID":"iron_boots","recipeDescription":"Boots (Iron)","recipeLocations":"0,0,0,1,0,1,1,0,1","usedImages":"air,iron_ingot","recipeID":9},{"recipeCategory":2,"recipeImageID":"diamond_leggings","recipeDescription":"Leggings (Diamond)","recipeLocations":"1,1,1,1,0,1,1,0,1","usedImages":"air,diamond_ingot","recipeID":10},{"recipeCategory":2,"recipeImageID":"gold_leggings","recipeDescription":"Leggings (Gold)","recipeLocations":"1,1,1,1,0,1,1,0,1","usedImages":"air,gold_ingot","recipeID":11},{"recipeCategory":2,"recipeImageID":"iron_leggings","recipeDescription":"Leggings (Iron)","recipeLocations":"1,1,1,1,0,1,1,0,1","usedImages":"air,iron_ingot","recipeID":12},{"recipeCategory":2,"recipeImageID":"diamond_chestplate","recipeDescription":"Chestplate (Diamond)","recipeLocations":"1,0,1,1,1,1,1,1,1","usedImages":"air,diamond_ingot","recipeID":13},{"recipeCategory":2,"recipeImageID":"gold_chestplate","recipeDescription":"Chestplate (Gold)","recipeLocations":"1,0,1,1,1,1,1,1,1","usedImages":"air,gold_ingot","recipeID":14},{"recipeCategory":2,"recipeImageID":"iron_chestplate","recipeDescription":"Chestplate (Iron)","recipeLocations":"1,0,1,1,1,1,1,1,1","usedImages":"air,iron_ingot","recipeID":15},{"recipeCategory":2,"recipeImageID":"diamond_helmet","recipeDescription":"Helmet (Diamond)","recipeLocations":"1,1,1,1,0,1,0,0,0","usedImages":"air,diamond_ingot","recipeID":16},{"recipeCategory":2,"recipeImageID":"gold_helmet","recipeDescription":"Helmet (Gold)","recipeLocations":"1,1,1,1,0,1,0,0,0","usedImages":"air,gold_ingot","recipeID":17},{"recipeCategory":2,"recipeImageID":"iron_helmet","recipeDescription":"Helmet
My question is, how can I convert this back into an arraylist (ArrayList<Item>)
There is already an Item class present in the client application.
I've read examples about the Gson library but it seems it's not included anymore when compiling in API 17.
What would be the easiest approach?
Download and include GSON jar from here in your project if using Eclipse.
If using Android Studio then open your build.gradle and add the below to your dependencies block. Or again you can choose not to use maven and simply drop the jar in your lib folder.
compile 'com.google.code.gson:gson:2.2.4'
Next, use GSON to construct a list of items.
Make sure you have your Item.java class with same member names as in the JSON response
List<Recipe> recipesList = new ArrayList<Recipe>();
HttpEntity jsonObj = response.getEntity();
String data = EntityUtils.toString(entity);
Log.d("TAG", data);
Gson gson = new GsonBuilder().create();
recipesList = gson.fromJson(data, new TypeToken<List<Item>>() {}.getType());
Make sure you handle the exceptions appropriately.
You could use Jackson to parse the incoming JSON. (Quick introduction)
If you already have a Class with the appropriate properties, it can be as easy as something like this:
public class Items {
private List<Item> items;
// getter+setter
}
ObjectMapper mapper = new ObjectMapper();
Items = mapper.readValue(src, Items.class);
See this for more information.
Step 1 : Item obj=new Item;
Step 2: Parse the json formar for example here :
[[Example1][1]
Step 3: while parsing put ur values in obj :
obj.recipeCategory=value1;
Step 4: insret ur obj into arraylist:
arrayList.add(obj);
I think you should using json-simple library to parse string Json to JsonObject and convert to simple data type.
Example:
JSONArray arrJson = (JSONArray) parser.parse("String json");
Get each element JSONObject in JSONArray, then parse it to simple data type:
long recipeCategory = (long) jsonObject.get("recipeCategory");
You can use Gson like many users said, here is an example of a RESTfull client using Gson:
public class RestRequest {
Gson gson = new Gson();
public <T> T post(String url, Class<T> clazz,
List<NameValuePair> parameters) {
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(url);
try {
// Add your data
httppost.setEntity(new UrlEncodedFormEntity(parameters));
// Execute HTTP Post Request
HttpResponse response = httpclient.execute(httppost);
StringBuilder json = inputStreamToString(response.getEntity()
.getContent());
T gsonObject = gson.fromJson(json.toString(), clazz);
return gsonObject;
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
// Fast Implementation
private StringBuilder inputStreamToString(InputStream is)
throws IOException {
String line = "";
StringBuilder total = new StringBuilder();
// Wrap a BufferedReader around the InputStream
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
// Read response until the end
while ((line = rd.readLine()) != null) {
total.append(line);
}
// Return full string
return total;
}
}
The usage will be something like this:
new RestRequest("myserver.com/rest/somewebservice", SomeClass.class, Arrays.asList(new BasicValuePair("postParameter", "someParameterValue")));
Where SomeClass.class will be Recipe[].class in your case. Also check this question to properly handle server side errors.
Man, google is your friend! A quick search for "android json" or "android json parse" gives you some nice tutorials like this one or this here.
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 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();
}
}
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();
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...
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");
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()
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.
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
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
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.
https://github.com/vishalchhodwani1992/httpLibrary