Question

I am calling rest web services from android . web service code is as follows

@Path("test")
public class Test
{

    @GET
    @Path("name/{name}")
    @Produces(MediaType.TEXT_PLAIN)
    public Response say(@PathParam("name") String name)
    {
        //return "Hello ......"+name;
        ResponseBuilder response = Response.ok((Object)"Hello ......"+name);
        return response.build();
    }
}

Android client code is as follows

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URLEncoder;
import java.security.KeyStore;
import java.util.ArrayList;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpVersion;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.conn.ClientConnectionManager;
import org.apache.http.conn.scheme.PlainSocketFactory;
import org.apache.http.conn.scheme.Scheme;
import org.apache.http.conn.scheme.SchemeRegistry;
import org.apache.http.conn.ssl.SSLSocketFactory;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.impl.conn.tsccm.ThreadSafeClientConnManager;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.BasicHttpParams;
import org.apache.http.params.HttpParams;
import org.apache.http.params.HttpProtocolParams;
import org.apache.http.protocol.HTTP;

import android.util.Log;

public class RestClient {

    private static final int GET = 1;
    private static final int POST = 2;
    private ArrayList <NameValuePair> params;
    private ArrayList <NameValuePair> headers;

    private String url;

    private int responseCode;
    private String message;

    private String response;

    public String getResponse() {
        return response;
    }

    public String getErrorMessage() {
        return message;
    }

    public int getResponseCode() {
        return responseCode;
    }

    public RestClient(String url)
    {
        this.url = url;
        params = new ArrayList<NameValuePair>();
        headers = new ArrayList<NameValuePair>();
    }

    public void AddParam(String name, String value)
    {
        params.add(new BasicNameValuePair(name, value));
    }

    public void AddHeader(String name, String value)
    {
        headers.add(new BasicNameValuePair(name, value));
    }

    public void Execute(int selection) throws Exception
    {
        switch(selection) {
            case GET:
            {
                //add parameters
                String combinedParams = "";
                if(!params.isEmpty()){
                    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
                for(NameValuePair h : headers)
                {
                    request.addHeader(h.getName(), h.getValue());
                }
                Log.d("prabhu","url......"+url + combinedParams);
                Log.d("prabhu","request......"+request);
                executeRequest(request, url);
                break;
            }
            case POST:
            {
                HttpPost request = new HttpPost(url);

                //add headers
                for(NameValuePair h : headers)
                {
                    request.addHeader(h.getName(), h.getValue());
                }

                if(!params.isEmpty()){
                    request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
                }

                executeRequest(request, url);

                Log.d("prabhu","url......"+url);
                break;
            }
        }
    }

    private void executeRequest(HttpUriRequest request, String url)
    {


         HttpClient client = null;

         try
         {

           KeyStore trustStore = KeyStore.getInstance(KeyStore.getDefaultType());
             trustStore.load(null, null);

             SSLSocketFactory sf = new MySSLSocketFactory(trustStore);
             sf.setHostnameVerifier(SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER);

             HttpParams params = new BasicHttpParams();
             HttpProtocolParams.setVersion(params, HttpVersion.HTTP_1_1);
             HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);

             SchemeRegistry registry = new SchemeRegistry();
             registry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));
             registry.register(new Scheme("https", sf, 443));

             ClientConnectionManager ccm = new ThreadSafeClientConnManager(params, registry);
             client = new DefaultHttpClient(ccm, params);
         }catch(Exception e)
         {

         }

        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);

                // Closing the input stream will trigger connection release
                instream.close();
            }

        } catch (ClientProtocolException e)  {
            client.getConnectionManager().shutdown();
            e.printStackTrace();
        } catch (IOException e) {
            client.getConnectionManager().shutdown();
            e.printStackTrace();
        }



    }

    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");
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }
}

Using the above class, I am calling URL(web service) like below

 RestClient client = new RestClient("http://localhost:8080/TestProject/test/name/madhu");


                try {
                    client.Execute(GET)
                } catch (Exception e) {
                    e.printStackTrace();
                }

                String response = client.getResponse();

If the server is running , every thing is working fine. But If Server is down ,how to handle the situation.

Answer 1

I think adding Connection and Socket Timeout for Http Request do the trick,

HttpParams httpParameters = new BasicHttpParams();
// Set the timeout in milliseconds until a connection is established.
int timeoutConnection = 3000;
HttpConnectionParams.setConnectionTimeout(httpParameters,timeoutConnection);
// Set the default socket timeout (SO_TIMEOUT)
// in milliseconds which is the timeout for waiting for data.
int timeoutSocket = 3000;
HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);