Requesting REST web service:   you request REST web services by calling a URL with the parameters. like this
http://example.com/resources/getitems

an example of calling a REST web service:
String callWebErvice(String serviceURL){
  // http get client
         HttpClient client=new DefaultHttpClient();
         HttpGet getRequest=new HttpGet();
         
         try {
          // construct a URI object
    getRequest.setURI(new URI(serviceURL));
   } catch (URISyntaxException e) {
    Log.e("URISyntaxException", e.toString());
   }
         
   // buffer reader to read the response
         BufferedReader in=null;
         // the service response
         HttpResponse response=null;
   try {
    // execute the request
    response = client.execute(getRequest);
   } catch (ClientProtocolException e) {
    Log.e("ClientProtocolException", e.toString());
   } catch (IOException e) {
    Log.e("IO exception", e.toString());
   }
         try {
    in=new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
   } catch (IllegalStateException e) {
    Log.e("IllegalStateException", e.toString());
   } catch (IOException e) {
    Log.e("IO exception", e.toString());
   }
         StringBuffer buff=new StringBuffer("");
         String line="";
         try {
    while((line=in.readLine())!=null)
    {
     buff.append(line);
    }
   } catch (IOException e) {
    Log.e("IO exception", e.toString());
    return e.getMessage();
   }
         
         
         try {
    in.close();
   } catch (IOException e) {
    Log.e("IO exception", e.toString());
   }
         // response, need to be parsed
         return buff.toString();
 }