datainputstream in.read（b）中缺少字节

Question

I'm trying to write a program which acts as a server that will read bytes from a client that is written in PHP - sends request via socket (which i cannot recode due to policy) Here is the server code: The server runs in: Red Hat Enterprise Linux Server release 6.2 (Santiago)

public void run() {
    try {
        serverSocket = new ServerSocket(port);
        serverSocket.setSoTimeout(0);            

        while(!isInterrupted) {
            try {                    
                Socket server = serverSocket.accept();

                LOG.info("Request received from : " + server.getRemoteSocketAddress());                    
                DataInputStream in = new DataInputStream(server.getInputStream());
                // DataInputStream in = new DataInputStream(
                //        new BufferedInputStream(server.getInputStream(), 10000));  

                byte[] bytes = new byte[10000];

                int byteDupLength = in.read(t_bytes);                    
                // in.readFully(bytes); // I tried this but to no avail
                // int byteDupLength = bytes.length;

                LOG.info(byteDupLength);                    
                byte[] byteDup = new byte[byteDupLength];                    
                System.arraycopy(bytes, 4, byteDup, 0, byteDupLength);

                // FOR INFORMATION ONLY
                /*for (byte b : byteDup){                        
                    LOG.info(b);

                }*/
                ByteBuffer buffer = ByteBuffer.wrap(byteDup);
                LOG.info(buffer);

                forwardRequest(byteDup);
                server.close();
            }
            catch(SocketTimeoutException s) {
                LOG.error("Socket timed out!", s);
                break;
            }
            catch(IOException e)
            {
                LOG.error("IOException:", e);
                break;
            }
        } 
    } 
    catch (IOException ex) {
        LOG.error("Server socket is null", ex);
    }
    LOG.fatal("ReceiverEngine interrupted!");
}

I encountered a problem when the client sends request consisting of 4948 bytes. The only bytes the server can read is 2090. Another thing that seems a mystery to me is that, when I run the server via Netbeans in my local (which is a Windows 7 Pro), it works as expected. I dont know what is wrong. Please help.. :)

Thanks!

Answer 1

1. TCP is a byte stream protocol.
2. The read() method isn't guaranteed to fill the buffer.

Therefore if you don't receive the expected number of bytes in a single read, you have to loop until you do receive them.

readFully() would have worked if the buffer size agreed with the size of what was sent. In your case you specified a buffer of 10,000 bytes, which weren't sent, so it would have blocked waiting for the other 10000-4948 bytes.