onlinescoring.java

J2ME Game Programming的隋书源代码

import javax.microedition.lcdui.*;
import javax.microedition.io.HttpConnection;
import javax.microedition.io.Connector;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class OnlineScoring extends Form implements CommandListener
{
   private int score;
   private Command cancel;
   private Command send;
   private Command ok;

   private HttpConnection httpConnection;

   public OnlineScoring(int scoreArg)
   {
      super("Online Score");
      score = scoreArg;

      append("Transmit score of " + score + "?");

      send = new Command("Send", Command.OK, 1);
      addCommand(send);
      cancel = new Command("Cancel", Command.CANCEL, 2);
      addCommand(cancel);

      setCommandListener(this);
   }

   public void showResult(String s)
   {
      append(s);
   }

   public void commandAction(Command c, Displayable s)
   {
      if (c == send)
      {
         // get rid of the send command from the form
         removeCommand(send);

         // create a new thread for the networking
         Thread t = new Thread()
         {
            // declare a run method (not called until the thread is started
            // (see t.start below)
            public void run()
            {
               // send score to the server and retrieve the resulting rank
               // WARNING: this method will STALL until we get a response
               // or it times out
               String result = transmitScore();

               // delete the current text item
               delete(0);

               // present the result to the player
               showResult(result);

               // get rid of the cancel command and add an OK
               removeCommand(cancel);
               ok = new Command("OK", Command.OK, 1);
               addCommand(ok);
            }
         };

         // start the thread (execute the contents of the run method above)
         t.start();
      }

      if (c == ok || c == cancel)
         StarAssault.getApp().activateMenu();
   }

   public String transmitScore()
   {
      InputStream in = null;
      OutputStream out = null;

      try
      {
         // submit score to server and read ranking response
         httpConnection = (HttpConnection) Connector.open("http://localhost:8080/StarAssault/updateScore");

         // close the connection after req/response (don't bother keeping it alive)
         httpConnection.setRequestProperty("Connection", "close");

         // setup for a post
         httpConnection.setRequestMethod(httpConnection.POST);
         String req = "" + score;
         httpConnection.setRequestProperty("Content-Length", Integer.toString(req.length()));

         // output the request
         out = httpConnection.openOutputStream();
         for (int i = 0; i < req.length(); i++)
            out.write(req.charAt(i));

         // read the result
         in = httpConnection.openInputStream();

         if (httpConnection.getResponseCode() == httpConnection.HTTP_OK)
         {
            int contentLength = (int) httpConnection.getLength();
            if (contentLength == -1) contentLength = 255;
            StringBuffer response = new StringBuffer(contentLength);

            for (int i = 0; i < contentLength; i++)
               response.append((char) in.read());

            String rankString = response.toString();
            return "You are currently ranked " + rankString + ".";
         }
         else
            throw new IOException();
      }

      catch (IOException e)
      {
         return "Error transmitting score.";
      }

      finally
      {
         if (httpConnection != null)
         {
            try
            {
               httpConnection.close();
            }

            catch (IOException ioe)
            {
            }
         }

         if (in != null)
         {
            try
            {
               in.close();
            }

            catch (IOException ioe)
            {
            }
         }

         if (out != null)
         {
            try
            {
               // clean up
               out.close();
            }

            catch (IOException ioe)
            {
            }
         }
      }
   }

}