How conform that a receiving file is completly received.

Question

i am sending a file.
how conform that a receiving file is completly received?

Answer 1

server code
package server;
import java.beans.XMLEncoder;
import java.io.*;
import java.net.*;
import java.nio.channels.FileLock;
import java.sql.ResultSet;
import java.util.ArrayList;
public class Server2 {
    public static void main(String args[]) {
        int port = 6789;
        Server2 server = new Server2(port);
        server.startServer();
    // declare a server socket and a client socket for the server;
    // declare the number of connections
    ServerSocket echoServer = null;
    Socket clientSocket = null;
    int numConnections = 0;
    int port;
    public Server2(int port) {
        this.port = port;
    public void stopServer() {
        System.out.println("Server cleaning up.");
        System.exit(0);
    public void startServer() {
        // Try to open a server socket on the given port
        // Note that we can't choose a port less than 1024 if we are not
        // privileged users (root)
        try {
            echoServer = new ServerSocket(port);
        } catch (IOException e) {
            System.out.println(e);
        System.out.println("Server is started and is waiting for connections.");
        System.out.println("With multi-threading, multiple connections are allowed.");
        System.out.println("Any client can send -1 to stop the server.");
        // Whenever a connection is received, start a new thread to process the connection
        // and wait for the next connection.
        while (true) {
            try {
                clientSocket = echoServer.accept();
                numConnections++;
                Server2Connection oneconnection = new Server2Connection(clientSocket, numConnections, this);
                new Thread(oneconnection).start();
            } catch (IOException e) {
                System.out.println(e);
class Server2Connection implements Runnable {
    //BufferedReader is;
    ObjectInputStream is;
    ObjectOutputStream os;
    XMLEncoder xml;
    Socket clientSocket;
    String numConn;
    int id;
    Server2 server;
FileLock fl ;
    public Server2Connection(Socket clientSocket, int id, Server2 server) {
        this.clientSocket = clientSocket;
        this.id = id;
        this.server = server;
        numConn = "Connection " + id + " established with: " + clientSocket;
        System.out.println("Connection " + id + " established with: " + clientSocket);
        try {
            is = new ObjectInputStream(clientSocket.getInputStream());
            os = new ObjectOutputStream(clientSocket.getOutputStream());
            //xml = new XMLEncoder(new BufferedOutputStream( new FileOutputStream("first.xml")));
          //  xml = new XMLEncoder(new BufferedOutputStream( new FileOutputStream("first.xml")));
            FileOutputStream fs = new FileOutputStream("first.xml");
            BufferedOutputStream br = new BufferedOutputStream(fs);
            xml = new XMLEncoder(br);
            //fl =  fs.getChannel().lock();
        } catch (IOException e) {
            System.out.println(e);
    public void run() {
        Object line;
        try {
            boolean serverStop = false;
            int n = 0;
            while (true) {
                line = is.readObject();
                if (line instanceof String) {
                    String s = (String) line;
                    System.out.println("In Server :: The input is " + s);
                    UserData ud = new UserData();
                    ud.setAdd("karachi");
                    ud.setId("123");
                    ud.setName("XML testing..");
                    System.out.println("Tring to lock locked..");
                    fl.channel().tryLock();
                    System.out.println("File locked..");
                    xml.writeObject(ud);
                    xml.flush();
                    //os.writeObject(ud);
                    n = Integer.parseInt(s);
                if (n == -1) {
                    serverStop = true;
                    break;
                if (n == 0) {
                    break;
            //  System.out.println("Connection " + id + " closed.");
            fl.release();
            is.close();
            os.close();
            xml.close();
            clientSocket.close();
            if (serverStop) {
                server.stopServer();
        } catch (Exception e) {
            System.out.println("Exception..." + e);
client code
* To change this template, choose Tools | Templates
* and open the template in the editor.
package scoket1;
import java.beans.XMLDecoder;
import server.UserData;
//import server.MyRS;
import java.io.*;
import java.net.*;
import java.sql.ResultSet;
import java.util.ArrayList;
import javax.swing.JOptionPane;
public class Client {
    public static void main(String[] args) {
        String hostname = "localhost";
        int port = 6789;
        // declaration section:
        // clientSocket: our client socket
        // os: output stream
        // is: input stream
        Socket clientSocket = null;
        ObjectOutputStream os = null;
        ObjectInputStream is = null;
        XMLDecoder de = null;
        // Initialization section:
        // Try to open a socket on the given port
        // Try to open input and output streams
        try {
            clientSocket = new Socket(hostname, port);
            os = new ObjectOutputStream(clientSocket.getOutputStream());
            is = new ObjectInputStream(clientSocket.getInputStream());
            de = new XMLDecoder(new BufferedInputStream(new FileInputStream("first.xml")));
        } catch (UnknownHostException e) {
            System.err.println("Don't know about host: " + hostname);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for the connection to: " + hostname);
        // If everything has been initialized then we want to write some data
        // to the socket we have opened a connection to on the given port
        if (clientSocket == null || os == null || is == null) {
            System.err.println("Something is wrong. One variable is null.");
            return;
        try {
            while (true) {
                System.out.print("Enter an integer (0 to stop connection, -1 to stop server): ");
                BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
                String keyboardInput = br.readLine();
                os.writeObject(keyboardInput);
                int n = Integer.parseInt(keyboardInput);
                if (n == 0 || n == -1) {
                    break;
//                Object responseObj = null;
//                responseObj = is.readObject();
                Object test = null;
                test = (Object) de.readObject();
                if (test instanceof String) {
                    String msg = (String) test;
                    System.out.println(msg);
                } else if (test instanceof UserData) {
                    System.out.println("XML File Test succesful .. be happy ..");
                    System.out.println("Array of User Data ..");
                    UserData ud = (UserData) test;
                    System.out.println("Name:-    " + ud.getName());
                    System.out.println("ID :-     " + ud.getId());
                    System.out.println("Address:- " + ud.getAdd());
            // clean up:
            // close the output stream
            // close the input stream
            // close the socket
            os.close();
            is.close();
            clientSocket.close();
        } catch (UnknownHostException e) {
            System.err.println("Trying to connect to unknown host: " + e);
        } catch (Exception e) {
            System.err.println("Exception:  " + e);
}