Problems sending files throught TCP sockets

Question

I would like to transfer a file throught a tcp socket, here there is what the sender program does :
try{
     File localFile = new File("shared/"+fileName);
     DataOutputStream oos = new DataOutputStream(socket.getOutputStream());     
     DataInputStream fis = new DataInputStream(new FileInputStream(localFile));
     while(fis.available() > 0){
          oos.writeByte(fis.readByte());
     catch(Exception e){}here what the receiver program does:
     try{
     File downloadFile = new File("incoming/"+fileName);
     downloadFile.createNewFile();
     ois = new DataInputStream(connectionSocket.getInputStream());
     fos = new DataOutputStream(new FileOutputStream(downloadFile));
     while(ois.available() > 0){
          fos.writeByte(ois.readByte());
     catch(Exception e){}
}Where i m wrong? it doesnt work :( , it just create the new file in the incoming folder, but its size remains 0 byte :(
help a newbye please :D

Answer 1

Your problem is probably related to the use of available. This is the amount that is currently in the buffer that you can read without blocking. For network programming you should expect to have to wait for data. Second, you are copying the data one byte at a time which is not very efficient. Try something like:
// Sender
try {
    File localFile = new File("shared/"+fileName);
    OutputStream out = socket.getOutputStream();     
    InputStream fis = new FileInputStream(localFile);
    int length;
    byte[] buffer = new byte[4096];
    while((length = fis.read(buffer)) != -1)
     out.write(buffer, 0, length);
    fis.close();
    out.close();
catch(Exception e){}
// Receiver
try {
    File downloadFile = new File("incoming/"+fileName);
    IntputStream ois = connectedSocket.getIntputStream();     
    OutputStream fos = new FileOutputStream(downloadFile);
    int length;
    byte[] buffer = new byte[4096];
    while((length = ois.read(buffer)) != -1)
     fos.write(buffer, 0, length);
    fos.close();
    ois.close();
catch(Exception e){}