How to call a RESTful web service from Android?

Question

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.

Answer 1

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();
    }
}