Question

I have implement a web service using jersey and I have a client making HTTP requests. The web service talks with a database. When the client makes a request, the server through a query retrieves some data from the database(list of contacts). I would like to return these data to the client(as a response). So now i am just trying to send a simple sting array from server to client.

Server Code:

package de.vogella.jersey.first;
import java.util.ArrayList;
import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
@Path("/hello2")
public class Hello2 {
//String msg3[] = {"one", "two"}; 
//ArrayList<String> listitems = new ArrayList<String>();

String msg2 = "message of the server";
// This method is called if TEXT_PLAIN is request
@GET
@Produces(MediaType.TEXT_PLAIN)
public String sayPlainTextHello() {
    System.out.println("TEXT_PLAIN is request Hello_2");
    return "Hello Jersey from Hello_2";
}

@POST
@Produces(MediaType.APPLICATION_OCTET_STREAM)   
public String[] authedication(@FormParam("username") String us, @FormParam("password") String pass){ 

    String msg3[] = {"one", "two"}; 
    System.out.println("these are the results of the Hello2");
    System.out.println("--------------------------------------------------");
    System.out.println("The name is \"" + us + "\" is request");
    System.out.println("The password is \"" + pass + "\" is request");
    System.out.println("--------------------------------------------------");

    return msg3;
}

}

Client Code:

  public void addContactsToList(){
  Log.v(TAG, "Load contacts");
  HttpClient client = new DefaultHttpClient();
  EditText etxt_user = (EditText) findViewById(R.id.username);
  EditText etxt_pass = (EditText) findViewById(R.id.password);
  String username1 = etxt_user.getText().toString();
  String password1 = etxt_pass.getText().toString();
  HttpPost httppost = new HttpPost("http://10.0.2.2:8080/de.vogella.jersey.first/rest/hello2");
  Log.v(TAG, "message1");         
  //add your Data
  List< NameValuePair > nvps = new ArrayList< NameValuePair >();
  nvps.add(new BasicNameValuePair("username", username1));
  nvps.add(new BasicNameValuePair("password", password1));

  try {
        UrlEncodedFormEntity p_entity = new UrlEncodedFormEntity(nvps, HTTP.UTF_8);

        httppost.setEntity(p_entity);
        //Execute HTTP Post Request
        Log.v(TAG, "The request has been sent.");
        HttpResponse response = client.execute(httppost);

        Log.v(TAG, response.getStatusLine().toString());
        HttpEntity responseEntity = response.getEntity();
        //final InputStream inputStream = responseEntity.getContent();

        String x = EntityUtils.toString(responseEntity);

        Log.v(TAG,x);
        removeDialog(1);
        Intent intent=new Intent(getApplicationContext(),TestM_chat4_all_contacts.class);
        intent.putExtra("Contacts",x);
        startActivity(intent);

  } catch (Exception e)
  {
        Intent intent = new Intent(getApplicationContext(), LoginError.class);//calls the activity LoginError.java
        intent.putExtra("LoginMessage", "Unable to load your contacts");
        startActivity(intent);
        removeDialog(0);
   }

}

So can i send an array or an arraylist from the server and how the client reads these data? Also I am thinking to use JSON, is this implemantation(send array) possible using JSON?

Thank you in Advance!

Answer 1

On server you shoud produce JSON

@Produces(MediaType.APPLICATION_JSON)

Then on client you can use Gson to convert it automatically to Java types. For array you’d use

String[] result = gson.fromJson(x, String[].class);