Java Code For FTP Using UDP
//server
import java.io.*;
import java.net.*;
class FTPUDPS
{
public static void main(String[] args)
{
DatagramSocket socket=null;
//Send, Receive packets
DatagramPacket inPacket=null;
DatagramPacket outPacket=null;
byte[] inBuf, outBuf;
final int PORT=50000;
try
{
socket=new DatagramSocket(PORT);
while(true)
{
System.out.println("\nRunning...\n");
//Receive Client's request
inBuf=new byte[100];
inPacket=new DatagramPacket(inBuf, inBuf.length);
socket.receive(inPacket);
//Get Port and IPAddress
int source_port=inPacket.getPort();
InetAddress source_address=inPacket.getAddress();
System.out.println("Client: "+source_address + ":" + source_port);
//Send File list
String dirname="/home/vaibhav/TextFiles/";
File f1=new File(dirname);
File fl[]=f1.listFiles();
StringBuilder sb=new StringBuilder("\n");
int c=0;
for(int i=0;i<fl.length;i++)
{
if(fl[i].canRead() && (fl[i].toString()).endsWith(".txt"))
c++;
}
sb.append(c+" .txt files found.\n\n");
for(int i=0;i<fl.length;i++)
if((fl[i].toString()).endsWith(".txt"))
sb.append(fl[i].getName()+" "+fl[i].length()+" Bytes\n");
sb.append("\nEnter file name for download: ");
outBuf=(sb.toString()).getBytes();
outPacket=new DatagramPacket(outBuf, 0, outBuf.length, source_address, source_port);
socket.send(outPacket);
//Receive Filename request
inBuf=new byte[100];
inPacket=new DatagramPacket(inBuf, inBuf.length);
socket.receive(inPacket);
String filename=new String(inPacket.getData(), 0, inPacket.getLength());
System.out.println("Requested File: "+filename);
boolean flis=false;
int index=-1;
sb=new StringBuilder("");
for(int i=0;i<fl.length;i++)
{
if(((fl[i].getName()).toString()).equalsIgnoreCase(filename))
{
index=i;
flis=true;
}
}
if(!flis)
{
System.out.println("ERROR");
sb.append("ERROR");
outBuf=(sb.toString()).getBytes();
outPacket=new DatagramPacket(outBuf, 0, outBuf.length, source_address, source_port);
socket.send(outPacket);
}
else
{
try
{
//File Send Process, Independent
File ff=new File(fl[index].getAbsolutePath());
FileReader fr=new FileReader(ff);
BufferedReader brf=new BufferedReader(fr);
String s=null;
sb=new StringBuilder();
while((s=brf.readLine())!=null)
{
sb.append(s);
}
if(brf.readLine()==null)
System.out.println("File Read Successful. Closing Socket.");
outBuf=(sb.toString()).getBytes();
outPacket=new DatagramPacket(outBuf, 0, outBuf.length, source_address, source_port);
socket.send(outPacket);
}
catch(IOException ioe)
{
System.out.println(ioe);
}
}
}
}
catch(Exception e)
{
System.out.println("Error\n");
}
}
}
//client
import java.io.*;
import java.net.*;
import java.util.Scanner;
class FTPUDPC
{
public static void main(String[] args)
{
DatagramSocket socket = null;
DatagramPacket inPacket = null;
DatagramPacket outPacket = null;
byte[] inBuf, outBuf;
final int PORT = 50000;
String msg = null;
Scanner src=new Scanner(System.in);
try
{
InetAddress address = InetAddress.getByName("127.0.0.1");
socket = new DatagramSocket();
msg = "";
outBuf = msg.getBytes();
outPacket = new DatagramPacket(outBuf, 0, outBuf.length, address, PORT);
socket.send(outPacket);
inBuf = new byte[65535];
inPacket = new DatagramPacket(inBuf, inBuf.length);
socket.receive(inPacket);
String data = new String(inPacket.getData(), 0, inPacket.getLength());
//Print file list
System.out.println(data);
//Send file name
String filename=src.nextLine();
outBuf = filename.getBytes();
outPacket = new DatagramPacket(outBuf, 0, outBuf.length,address, PORT);
socket.send(outPacket);
//Receive file
inBuf = new byte[100000];
inPacket = new DatagramPacket(inBuf, inBuf.length);
socket.receive(inPacket);
data = new String(inPacket.getData(), 0, inPacket.getLength());
if(data.endsWith("ERROR"))
{
System.out.println("File doesn't exist.\n");
socket.close();
}
else
{
try
{
BufferedWriter pw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(filename)));
pw.write(data);
//Force write buffer to File
pw.close();
System.out.println("File Write Successful. Closing Socket.");
socket.close();
}
catch(IOException ioe)
{
System.out.println("File Error\n");
socket.close();
}
}
}
catch (Exception e)
{
System.out.println("\nNetwork error. Please try again.\n");
}
}
}
0 comments :