Rookie Rookie - 1 month ago 15
Java Question

Java sending and receiving file (byte[]) over sockets

I am trying to develop a very simple client / server where the client converts a file to bytes, sends it to the server, and then converts the bytes back in to a file.

Currently the program just creates an empty file. I'm not a fantastic Java developer so any help much appreciated.

This is the server part that receives what the client sends.

ServerSocket serverSocket = null;

serverSocket = new ServerSocket(4444);


Socket socket = null;
socket = serverSocket.accept();

DataOutputStream out = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
DataInputStream in = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
byte[] bytes = new byte[1024];

in.read(bytes);
System.out.println(bytes);

FileOutputStream fos = new FileOutputStream("C:\\test2.xml");
fos.write(bytes);


And here is the client part

Socket socket = null;
DataOutputStream out = null;
DataInputStream in = null;
String host = "127.0.0.1";

socket = new Socket(host, 4444);
out = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
in = new DataInputStream(new BufferedInputStream(socket.getInputStream()));

File file = new File("C:\\test.xml");
//InputStream is = new FileInputStream(file);
// Get the size of the file
long length = file.length();
if (length > Integer.MAX_VALUE) {
System.out.println("File is too large.");
}
byte[] bytes = new byte[(int) length];

//out.write(bytes);
System.out.println(bytes);

out.close();
in.close();
socket.close();

Answer

Thanks for the help, I've managed to get it working now so thought I would post so that the others can use to help them.

Server

public class Server {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = null;

        try {
            serverSocket = new ServerSocket(4444);
        } catch (IOException ex) {
            System.out.println("Can't setup server on this port number. ");
        }

        Socket socket = null;
        InputStream in = null;
        OutputStream out = null;

        try {
            socket = serverSocket.accept();
        } catch (IOException ex) {
            System.out.println("Can't accept client connection. ");
        }

        try {
            in = socket.getInputStream();
        } catch (IOException ex) {
            System.out.println("Can't get socket input stream. ");
        }

        try {
            out = new FileOutputStream("M:\\test2.xml");
        } catch (FileNotFoundException ex) {
            System.out.println("File not found. ");
        }

        byte[] bytes = new byte[16*1024];

        int count;
        while ((count = in.read(bytes)) > 0) {
            out.write(bytes, 0, count);
        }

        out.close();
        in.close();
        socket.close();
        serverSocket.close();
    }
}

and the Client

public class Client {
    public static void main(String[] args) throws IOException {
        Socket socket = null;
        String host = "127.0.0.1";

        socket = new Socket(host, 4444);

        File file = new File("M:\\test.xml");
        // Get the size of the file
        long length = file.length();
        byte[] bytes = new byte[16 * 1024];
        InputStream in = new FileInputStream(file);
        OutputStream out = socket.getOutputStream();

        int count;
        while ((count = in.read(bytes)) > 0) {
            out.write(bytes, 0, count);
        }

        out.close();
        in.close();
        socket.close();
    }
}
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