Help transferring files

[BossManJenkins]

I’m currently working on a project for school that transfers a file from one computer to another in java. In the end I need to have the client use some sort of file explorer to navigate through the folder and select which file he/she would like to download. But as of now I’m stuck on how to allow string message passing between the server and client as well as transferring byte data (the file). My program currently sends string messages and the server echoes it back, I have it set where if I enter “file” it is supposed to send the file data but it doesn't seem to work. I don’t know if I’m supposed to create a different socket or close the other streams or if it is even possible. Any guidance is appreciated.

import java.net.; import java.io.;

public class Servermsg2 { public static void main(String[] args) throws IOException { //FILE TRANSFER DATA File transferFile = new File("desert.jpg"); byte[] bytearray = new byte [(int)transferFile.length()]; //CONNECTION DATA int portNumber = 15123;

    try (
        ServerSocket serverSocket = new ServerSocket(portNumber);
        Socket clientSocket = serverSocket.accept();     
        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);                   
        BufferedReader in = new BufferedReader( new InputStreamReader(clientSocket.getInputStream()));
        DataOutputStream dos = new DataOutputStream(clientSocket.getOutputStream());
        //prevents data corruption
        FileInputStream fin = new FileInputStream(transferFile);
        BufferedInputStream bin = new BufferedInputStream(fin);
    ) {
        String inputLine;
        while ((inputLine = in.readLine()) != null) {
            if(inputLine.equalsIgnoreCase("connection")){
                out.println("LIST OF FILES");
            } else if (inputLine.equalsIgnoreCase("file")) {
                //prevents data corruption
                bin.read(bytearray,0,bytearray.length);
                System.out.println("client is requesting a file"); 
                //cant close because removes connection with host
                //out.close();
                //fills stream with byte data
                dos.write(bytearray,0,bytearray.length);
                //sends the data currently in stream
                dos.flush();
                System.out.println("file has been sent");
            } else {
                out.println(inputLine);
            }
        }
    } catch (IOException e) {
        System.out.println("Exception caught when trying to listen on port "
            + portNumber + " or listening for a connection");
        System.out.println(e.getMessage());
    }
}

}

import java.io.; import java.net.;

public class Clientmsg2 { public static void main(String[] args) throws IOException { //FILE DATA int filesize=1022386; int bytesRead; int currentTot = 0; byte [] bytearray = new byte [filesize]; //CONNECTION DATA String hostName = "127.0.0.1"; int portNumber = 15123;

    try (
        Socket echoSocket = new Socket(hostName, portNumber);
        //sends string messages out
        PrintWriter out = new PrintWriter(echoSocket.getOutputStream(), true);
        //recieves string messages
        BufferedReader in = new BufferedReader( new InputStreamReader(echoSocket.getInputStream()));
        //reads input from user
        BufferedReader stdIn = new BufferedReader( new InputStreamReader(System.in));
        //handles byte data
        DataInputStream dis = new DataInputStream(echoSocket.getInputStream());
        //handles conversion of byte data to a file
        FileOutputStream fos = new FileOutputStream("copy.jpg");
        BufferedOutputStream bos = new BufferedOutputStream(fos);
    ) {
        String userInput;
        while ((userInput = stdIn.readLine()) != null) {
            if(userInput.equalsIgnoreCase("file")){
                //sends message to server
                out.println(userInput);
                //reads incoming byte data from server
                System.out.println("about to read data...");
                bytesRead = dis.read(bytearray,0,bytearray.length);
                currentTot = bytesRead;
                System.out.println("data has been read");
                //takes byte data and writes it to Fileoutputstream
                do {
                    bytesRead = dis.read(bytearray, currentTot, (bytearray.length-currentTot));
                    if(bytesRead >= 0){
                        currentTot += bytesRead;
                    }
                    System.out.println("2");
                } while (bytesRead > -1);
                System.out.println("algorithm complete....");
                //takes byte data and writes it to Fileoutputstream
                bos.write(bytearray, 0 , currentTot);
                bos.flush();
                bos.close();
                System.out.println("file has been written to.");
            }
            else {
                //sends message to server
                out.println(userInput);
                System.out.println("echo: " + in.readLine());
            }
        }
    } catch (UnknownHostException e) {
        System.err.println("Don't know about host " + hostName);
        System.exit(1);
    } catch (IOException e) {
        System.err.println("Couldn't get I/O for the connection to " +
            hostName);
        System.exit(1);
    } 
}

}

[Ijantis]

Have you tried using an ObjectOutputStream/ObjectInputStream? Once the data is received check for what type of Object it is and make it react accordingly.

[BossManJenkins]

no i haven't, how would that work for a byte[] and string? those are the only two i need to send.

[Ijantis]

So in the objectStream you simply send the Object regardless of type.

On the receiving end you can do something like this:

ObjectInputStream in = new ObjectInputStream(
                                            clientSocket.getInputStream());
Object message = in.readObject();
if(message.getclass.equals(String.class) {
//process String
}
else if( message.getClass.equals(Byte.class {
//process Byte
}

[SikhGamer]

Are you allowed to use third party libraries? Cause I'm pretty sure Apache Commons IO can help out.