Re: Socket IO

From:

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer,comp.lang.java.help

Date:

Tue, 15 Apr 2008 22:05:25 -0400

Message-ID:

<48055ede$0$90276$14726298@news.sunsite.dk>

Chase Preuninger wrote:

I am writing a program that transfers files over a socket, the only
problem is that when the receiving side calls the read method it
always returns -1.

A few things seems "unusual" to me:

1) The order you are closing streams and sockets in - I would
close streams before socket.

2) Maybe a flush when writing would be a good idea.

3) Single byte read and write are very inefficient (even when
buffered).

Arne

//SENDING END
    public void run()
    {
        Socket s = null;
        InputStream in = null;
        try
        {
            s = server.accept();

if(s.getInetAddress().getHostAddress().equalsIgnoreCase(validIP))
            {
                in = new BufferedInputStream(new
FileInputStream(from));
                OutputStream out = new
BufferedOutputStream(s.getOutputStream());
                for(int b = in.read(); b != -1; b = in.read())
                {
                    out.write(b);
                }
                out.flush();
            }
        }
        catch(Exception ex)
        {
            ex.printStackTrace();
        }
        finally
        {
            try
            {
                s.close();
            }
            catch(Exception ex){}
            try
            {
                server.close();
            }
            catch(Exception ex){}
            try
            {
                in.close();
            }
            catch(Exception ex){}
        }
    }

//DOWNLOADING SIDE
    public void run()
    {
        Socket s = new Socket();
        OutputStream out = null;
        try
        {
            s.connect(addr);
            ProgressMonitorInputStream in = new
ProgressMonitorInputStream(parent, "Downloading " + file,
s.getInputStream());
            in.getProgressMonitor().setMaximum(1000);
            out = new BufferedOutputStream(new FileOutputStream(to));
            int b;
            int read = 0;
            while(!s.isClosed() && (b = in.read()) != -1)
            {
                out.write(b);
                read++;
                double frac = (double)read / (double)size;
                frac *= 1000;
                in.getProgressMonitor().setProgress((int)frac);
            }
        }
        catch(Exception ex)
        {
            ex.printStackTrace();
        }
        finally
        {
            if(s != null && s.isConnected())
            {
                try
                {
                    s.close();
                }
                catch(Exception ex){}
            }
            if(out != null)
            {
                try
                {
                    out.close();
                }
                catch(Exception ex){}
            }
        }
    }