File transfer through socket

Question

Sorry But I've changed the question.

In this code if the files are sent at the first time(no matter the number files i'm sending.) the code works fine. But when I put the FileSender in a loop to send files one by one, after the first transfer, the data received on the receiver's end is arbitrary(if checked during debugging) and it wouldn't even receive the files. Here's the change which I've done and it's not working. FileSender.java

import java.io.OutputStream;
import java.io.File;
import java.net.Socket;
public class FileSender {
public  void main(Socket socket,String[] args) {
try {

  OutputStream os     = socket.getOutputStream();
  int cnt_files = args.length;

  // How many files?
  ByteStream.toStream(os, cnt_files);

  for (int cur_file=0; cur_file<cnt_files; cur_file++) {
    ByteStream.toStream(os, new File(args[cur_file]).getName());
    ByteStream.toStream(os, new File(args[cur_file]));
  }
}
catch (Exception ex) {
  ex.printStackTrace();
}
}
}

String[] args contains the path of the files to be transmitted.

FileReceiver.java

import java.io.File;
import java.io.InputStream;
import java.net.Socket;

public class FileReceiver {

public void main(Socket socket,String arg) {
try {
    InputStream in = socket.getInputStream();

  int nof_files = ByteStream.toInt(in);
System.out.println("reach 1     "+ nof_files);
  for (int cur_file=0;cur_file < nof_files; cur_file++) {
    String file_name = ByteStream.toString(in);

    File file=new File(arg+file_name);
    System.out.println("Received path is :  "+file);
    ByteStream.toFile(in, file);
  }

}
catch (java.lang.Exception ex) {
  ex.printStackTrace(System.out);
}
}

}

arg contains the path at which the files is to be stored.

I want that i call the main functions mentioned whenever i want to transfer the file. Basically i want to transfer multiple files which can contain directories as well. to do this I've written the following code.

ServerFile.java

import java.io.*;
import java.net.*;
public class ClientFile implements Runnable{
Socket clientsocket;
public void run() {
    try
    {
        clientsocket = new Socket("219.64.189.14",6789);
    // Some code
    copy(outtoserver,infromserver, files);      // files contains the path of files to be transferred.
    // Some code
        clientsocket.close();
    }
    catch(Exception e2)
    {
            System.out.println("ClientFile   "+String.valueOf(e2) + "\n");
    }
}
public void copy(DataOutputStream outtoserver,BufferedReader infromserver,String[] files)
{
    try
    {
        FileSender fs = new FileSender();
        int totalfiles=0;
        int r=0;
        File oldfile;
        outtoserver.write(files.length);
        String chk;
        while(totalfiles<files.length)
        {

            oldfile = new File(files[totalfiles]);
            if(oldfile.isDirectory())
            {
                outtoserver.writeBytes("folder\n");
                File folder1[] = oldfile.listFiles();
                String[] folder = new String[folder1.length];
                int count=0;
                for(File name : folder1)
                {
                    folder[count] = name + "";
                    System.out.println(folder[count]);
                    count++;
                }
                outtoserver.writeBytes(oldfile.getName()+"\n");
                fs.main(clientsocket, folder);

            }
            else if(oldfile.isFile())
            {
                outtoserver.writeBytes("file\n");
        chk = infromserver.readLine();
                if(chk.equals("send"))
                {
                    outtoserver.writeBytes(oldfile.getName()+"\n");
                    String[] folder = new String[]{oldfile.getAbsolutePath()};
                    fs.main(clientsocket, folder);
                }
                totalfiles++;
                outtoserver.flush();

            }
        }
    }
    catch(Exception e)
    {
        System.out.println("ClientFile -->>  "+e.toString());
    }
}
}

ClientFile.java

import java.io.*;
import java.net.*;
import javax.swing.*;
class ServerFile implements Runnable {
Socket conn;
public ServerFile(Socket a)
{
    conn = a;
}
public void run() {
    File file1;
    String clientsen="";
    try
    {  // Some code
       copy(outtoclient,infromclient,file1.getAbsolutePath());      //file1 is the directory to which the file has to stored.    
   // some code
    }      
    catch(Exception e0)
    {
         System.out.println("ServerFile   "+String.valueOf(e0)+"\n"+e0.getCause());
    }
}//end main
public void copy(DataOutputStream outtoclient,BufferedReader infromclient,String basepath)
{
    try
    {
         FileReceiver fr = new FileReceiver();
         int totfiles = infromclient.read();
         int tot=0;
         File file;
         String path = null,chk;
         while(tot<totfiles)
         {
             chk = infromclient.readLine();
             if(chk.equals("file"))
             {
                outtoclient.writeBytes("send\n");
                path = infromclient.readLine();
                path = basepath+File.separator+path;
                file=new File(path);
                fr.main(conn, basepath+File.separator);
             }
             else if(chk.equals("folder"))
             {
                 String name = infromclient.readLine();
                 name = basepath+File.separator+name;
                 new File(name).mkdir();
                 fr.main(conn, name+File.separator);
             }
             tot++;
         }
    }
    catch(Exception e)
    {
        System.out.println("Server file:    "+e.toString());
    }
}

}//end class

Correct me by all means if I'm wrong.

Any help appreciated.

Answer 1

It looks like you are trying to set the number of files to one ( ByteStream.toStream(os, 1); ), but then you send all the files (from 0 to cnt_files-1, in the inner loop), then the args[0] thing to attempt to use the next file in args[]. There's problems with this to begin with, since what I think you're trying to do is something more along the lines of:

for(int i =0; i<n;i++){
    ByteStream.toStream(os, 1);//cnt_files);
    ByteStream.toStream(os, args[i]);
    ByteStream.toStream(os, new File(args[i]));
}

That still won't work though, because on the other end the FileReceiver has this:

int nof_files = ByteStream.toInt(in);

So the first thing the FileReceiver does is see how many files to expect. It'll see just 1, and its loop will end and the other files won't be read.

If by "one by one" you mean one file per connection, then you'd want something like this:

public static void main(String[] args) {

    try {
        for(int i =0; i<args.length;i++){
            Socket socket = new Socket(host, port);
            OutputStream os = socket.getOutputStream();

            ByteStream.toStream(os, 1);//cnt_files);
            ByteStream.toStream(os, args[i]);
            ByteStream.toStream(os, new File(args[i]));

            os.close();
            socket.close();
        }
     }
     catch(Exception e) {
         e.printStackTrace();
     }
}