Sending files from client to server using Sockets but getting some files with size zero

Question

i'm writing some code where

1. client takes file names(text files) from command Line
2. client converts each file to byte array and then send this array to server.
3. server starts a new thread , each thread is converting a byte array to new file in some specified directory.

My client code is

for Client Side

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

class Client
{
    public static void main(String args[])
    {
        try
        {
            int len=args.length;
            if(len== 0)
            {
                System.out.println("Invalid Number of Arguements");
                throw new Exception();
            }
            else
            {
                int i=0;
                while(i<len)
                {          
                    Socket s=new Socket("localhost",2222);
                    File f=new File(args[i++]);
                    if(f.exists())
                    {
                        OutputStream os=s.getOutputStream();
                        FileInputStream fr=new FileInputStream(f);
                        s.setSendBufferSize(fr.available());
                        byte data[]=new byte[fr.available()];
                        fr.read(data);
                        os.write(data);
                        os.flush();
                        os.close();
                        System.out.println("Sending file : "+f.getName()+" with size "+data.length);
                        fr.close();
                    }
                    else
                    {
                        System.out.println("File : "+args[i++]+" doesn't exist.");
                    }

                    s.close();
                }
            }
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }
}

for Server Side

import java.net.*;
import java.io.*;
import java.util.Date;

public class Server
{
    public static final String dir_to_store_files="c:\\myfiles\\";

    public static void main(String[] args) throws Exception
    {
        ServerSocket ss=new ServerSocket(2222);
        ss.setReceiveBufferSize(51200);
        ss.setReuseAddress(true);

        Socket s=null;
        while( (s=ss.accept()) != null)
        {
            new Thread(new ServerThreads(s,dir_to_store_files)).start();
            s=null;
        }
        ss.close();
    }
}

class ServerThreads implements Runnable
{
    private static int fileNounce=0;
    Socket s;
    String directory;

    ServerThreads(Socket s,String directory)
    {
        this.s=s;
        this.directory=directory;
    }

    public void run()
    {
        try
        {
            InputStream is=s.getInputStream();
            File f=new File(directory+"\\NewFile-"+fileNounce+".txt");
            while(f.exists())
            {
                    fileNounce++;
                    f=new File(directory+"\\NewFile "+fileNounce+".txt");
            }

            fileNounce++;
            f.createNewFile();

            FileOutputStream fos=new FileOutputStream(f);
            byte data[]=new byte[is.available()];
            System.out.print(is.available()+ " bytes are received from "+s.getRemoteSocketAddress());
            is.read(data);
            System.out.println("\t\tCreating file : "+f.getAbsolutePath()+" at : "+new Date()+" of size : "+data.length);
            is.close();
            fos.write(data);
            fos.flush();
            fos.close();
            s.close();
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }
}

The Problem : Server is unable to get files correctly means sometimes the new files are created with zero size(no data).For example i have checked with sending 239 c-files using java Client *c Server is receiving random number of files (in range 180-235) Even some files which it receives are of zero size.

Answer 1

fr.available() is not what you think it is.... You want File.length(), and a loop for reading the file bytes to send to the server...

is.available() is also wrong .. .consider a client side that looks like:

byte[] buffer = new byte[4096];
int len = 0;
while ((len = fr.read(buffer)) >= 0) {
   os.write(buffer, 0, len);
}