Re: SERVLET: Http Connection doesn't send data

From:
Godofredo <dejonghcito@gmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
Sun, 6 Jan 2008 07:01:08 -0800 (PST)
Message-ID:
<c504dad8-077c-4c69-8b0d-cc3db7ce8201@f47g2000hsd.googlegroups.com>
On Jan 5, 8:39 am, jmackqu...@gmail.com wrote:

I'm trying to write an application client/server with http protocol,
in JAVA. I need:

- client connects to the server,and after that,
- server continuously sends data to the client (as soon as they can be
obtained by an other server-side resource !! )

Client-side code is:

                        HttpURLConnectionis = httpConnection.getInputStream();

                        ObjectInputStream ois = new ObjectInputStream(is);
                        String toWrite=null;
                        do {
                                toWrite=(String)ois.readObject();
                        }
                        while(Thread.currentThread().isAlive());
                        is.close();

Server-side code (part of method doGet() of a servlet) is:

                        ObjectOutputStream os= new ObjectOutputStream
(response.getOutputStream());
                        Signal sig; // Signal is a Java Class containing String messages

                        int i=0;
                        while (i<10) {
                                sig = obs.getSignal(); // "obs" is a LinkedBlockingQueue!!!!
                                os.writeObject(new String(sig.getValue())); // sig.getValue()
returns String
                        }

The problem is that data sent from server arrives to client ALL at the
end of the while-cicle, and not one by one!

Istead, by using a code like this:

                        ObjectOutputStream os= new ObjectOutputStream
(response.getOutputStream());
                        int j=0;
                        while(true){
                                os.writeObject(new String("\n SERVER: count"+j));
                                j++;
                        }

...data arrives one by one!

I made lots of tries, variously modifying the code..and I noticed that
the problem is in using blocking methods
(in fact, the behaviour is same if forcing the current Thread to sleep
- eg Thread.sleep(1000) -).

Where's the problem??


Try os.flush();
Best wishes
Alex

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