Question

I’m trying to transfer files between client-server if the file is bigger than 12MB than it sends by blocks otherwise it sends normally. my main problem is that everytime I transfer something it gets more bytes than the original one, and I need to use digest messages after I complete this so it wont work the way it is, and the other one is when I try to send a file by network the client reads the file to send faster than the server writes it so client closes the program closing the connection, corrupting the file. my transfer code is below:

this is the client transfer code:

   if(fSize>maxfileSize){
        totbLidos = 0;
        byte[] fBytes = new byte[fBsize];
        while(totbLidos < fSize){
            int bRemain = (int) f.length() - totbLidos;
            if(bRemain < fBsize){
                fBsize = bRemain;
            }
            int bRead = tFile.read(fBytes, 0, fBsize);
            tServidor.write(fBytes, 0, fBsize);
            tServidor.flush();
            if(bRead>0){
                totbLidos+=bRead;
            }

            System.out.println("Total Bytes Lidos: " + totbLidos);

        }

        tFile.close();
        System.out.println("Ficheiro enviado");
        cliente.close();
    }
    else{
        totbLidos = 0;
        byte[] fBytes = new byte[fSize];
        while(totbLidos < fSize){
            int bRead = tFile.read(fBytes,0,fSize);
            if(bRead>0){
                totbLidos+=bRead;
            }
            tServidor.write(fBytes, 0, fSize);
            System.out.println("Total Bytes Lidos: " + totbLidos);
            tServidor.flush();
        }
        tFile.close();
        System.out.println("Ficheiro enviado");
        cliente.close();
    }
 }

server transfer code:

if(fSize > maxfileSize){
            totbLidos = 0;
            DataInputStream tFile = new DataInputStream(cliente.getInputStream());
            BufferedOutputStream fos = new BufferedOutputStream(new FileOutputStream(fName));
            byte[] fBytes = new byte[fBsize];
            while(totbLidos < fSize){
                int bRemain = size - totbLidos;
                if(bRemain < fBsize){
                    fBsize = bRemain;
                }
                int bRead = tFile.read(fBytes, 0, fBsize);
                fos.write(fBytes);
                fos.flush();
                if(bRead>0){
                    totbLidos+=bRead;
                }
                System.out.println("Bytes lidos: " + bRead);
                System.out.println("Total Bytes Escritos: " + totbLidos);
            }
            System.out.println("Ficheiro recebido");

            fos.close();
            tFile.close();
            cliente.close();
            servidor.close();
        }
        else if(fSize < maxfileSize){
            totbLidos = 0;
            DataInputStream tFile = new DataInputStream(cliente.getInputStream());
            BufferedOutputStream fos = new BufferedOutputStream(new FileOutputStream(fName));
            byte[] fBytes = new byte[fSize];
            while(totbLidos < fSize){
                int bRead = tFile.read(fBytes,0,fSize);
                fos.write(fBytes);
                fos.flush();
                if(bRead>0){
                    totbLidos+=bRead;
                }
                System.out.println("Total Bytes Escritos: " + totbLidos);
            }
            System.out.println("Ficheiro recebido");
            fos.close();
            tFile.close();
            cliente.close();
            servidor.close();
        }
}

Answer 1

You are not writing the same number of bytes you read here.

fos.write(fBytes);

try using

fos.write(fBytes, 0, bRead);