Reading a file into byte array and transferring it to be read into a new file

Question

My project is to write a server and client class. The server waits to receive a path for a file which it will convert from CSV to XML and then it's supposed to read the contents of the file back to the client who will save the content into a new file. I've gotten 90% of it done so far, the only thing is that the file in the end comes out empty, but on the server side the XML file is created.

This is the servers connection handling method

public void handleConnection(InputStream sockInput, OutputStream sockOutput){
    CsvToXml csv = new CsvToXml();
    String csvAddress;

    while(true)
    {
        byte[] buffer = new byte[4094];
        int bytes_read = 0;
        byte[] bytes_out = new byte[4094];

        try {
            bytes_read = sockInput.read(buffer, 0, buffer.length);
            csvAddress = new String(buffer, 0, bytes_read);
            System.err.println(csvAddress);
            csv.convertFile(csvAddress , "C:/Users/Arian/Desktop/xmlFile.xml", ",");

            if(bytes_read < 0){
                System.err.println("Tried to read from socket, but returned < 0. Closing socket.");
                return;
            }


            System.out.println("Server Received "+ bytes_read + "bytes, data=" + (new String(buffer, 0, bytes_read)));


            bytes_out = readXml();
            bytes_read = sockInput.read(bytes_out, 0, bytes_out.length);
            sockOutput.write(bytes_out);

            sockOutput.flush();
        } catch(Exception e){
            System.err.println("Exception reading/writing from/to socket, e=" +e);
            e.printStackTrace(System.err);
            return;
        }
    }
}

So this part I read and put the xml file into a byte array and return it.

public byte[] readXml(){

    File file = new File("C:/Users/Arian/Desktop/xmlFile.xml");
    byte[] xmlFile = new byte[(int)file.length()];
    FileInputStream fileInputStream = null;


    try {
        fileInputStream = new FileInputStream(file);
        fileInputStream.read(xmlFile);
        fileInputStream.close();
    } catch (Exception e) {
        System.err.println("File not found or unreadable.");
        e.printStackTrace();
    }

    return xmlFile;
}

and this is the clients inputStream and outputStream method

public void startConversion(int iterations) {

    System.err.println("Opening connection to "+serverHostname+" port "+serverPort);
    try {
        sock = new Socket(serverHostname, serverPort);
        sockInput = sock.getInputStream();
        sockOutput = sock.getOutputStream();
    } catch (IOException e) {
        e.printStackTrace(System.err);
        return;
    }

    System.err.println("About to start reading/rwriting to/from socket");   

    for(int i = 1; i <= iterations; i++){
        try{
            sockOutput.write(data, 0, data.length);
            File file = new File("C:/Users/Arian/Desktop/NewFile.xml");
            byte[] buffer = new byte[sockInput.available()];
            sockOutput = new FileOutputStream(file);
            int len;
            sockInput.read(buffer);
            sockOutput.write(buffer);
            sockOutput.flush();


        } catch(IOException e){
            e.printStackTrace(System.err);
        }






    System.err.println("Done reading/writing to/from socket, closing socket.");

    try {
        sock.close();
    } catch (IOException e){
        System.err.println("Exception closing socket.");
        e.printStackTrace(System.err);
    }

    System.err.println("Exiting.");
    }



}

I've tried many methods i've looked up on other posts and just haven't had any success with any of them. I cant post more than two links so heres my server and client class, my conversion class is fine anyway.

http://pastebin.com/C34hVNEW - Client Class http://pastebin.com/CF6BJTMP - Server Class

UPDATE:

I changed the for loop inside my client class to this and it still doesn't work. I put a comment where the client stops debugging.

    for(int i = 1; i <= iterations; i++){
        try{
            sockOutput.write(data, 0, data.length);
            File file = new File("C:/Users/Arian/Desktop/NewFile.xml");
            byte[] buffer = new byte[8192];
            sockOutput = new FileOutputStream(file);
            int count;
            while((count = sockInput.read(buffer)) > 0){ //The client stops debugging here.
                sockOutput.write(buffer, 0, count); 
            }
            sockOutput.flush();


        } catch(IOException e){
            e.printStackTrace(System.err);
        }

Answer 1

You're making a real meal out of this. The standard way to copy between streams in Java is as follows:

int count;
byte[] buffer = new byte[8192]; // or whatever you like, any size greater than zero
while ((count = in.read(buffer)) > 0)
{
  out.write(buffer, 0, count);
}

Note that you have to loop; that you don't need a buffer the size of the input; and that you have to use the read count when wrting, as read() isn't obliged to fill the buffer, and almost certainly won't on at least the last read before EOS. You can use this same code at both ends, by suitable adjustment of in and out.