how to convert thread to multi thread? - multithreading

Question

I want to the following code to convert the thread to newFixedThreadpool()
how do I do it?
//saddddddddddddddddddddddddddddffgfggggggggggggggggggggggggfdhfdhfdhdhdfhjhljgjhgdadsadsafds
class client :
import java.io.File;
import java.io.FileInputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.Socket;
import java.util.Arrays;
import java.lang.*;
import java.util.Scanner;
public class Client {
public static void main(String[] args) throws Exception {
String fileName = null;
try {
fileName = args[0];
} catch (Exception e) {
System.out.println("Enter the name of the file :");
Scanner scanner = new Scanner(System.in);
String file_name = scanner.nextLine();
File file = new File(file_name);
Socket socket = new Socket("localhost", 3332);
ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());
ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());
oos.writeObject(file.getName());
FileInputStream fis = new FileInputStream(file);
byte [] buffer = new byte[Server.BUFFER_SIZE];
Integer bytesRead = 0;
while ((bytesRead = fis.read(buffer)) > 0) {
oos.writeObject(bytesRead);
oos.writeObject(Arrays.copyOf(buffer, buffer.length));
}
oos.close();
ois.close();
System.exit(0);
}
}
}
class server:
import java.io.FileOutputStream;
import java.io.*;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.net.Socket;
public class Server extends Thread {
public static final int PORT = 3332;
public static final int BUFFER_SIZE = 100;
public void run() {
try {
ServerSocket serverSocket = new ServerSocket(PORT);
while (true) {
Socket s = serverSocket.accept();
saveFile(s);
}
} catch (Exception e) {
e.printStackTrace();
}
}
private void saveFile(Socket socket) throws Exception {
ObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());
ObjectInputStream ois = new ObjectInputStream(socket.getInputStream());
FileOutputStream fos = null;
byte [] buffer = new byte[BUFFER_SIZE];
Object o = ois.readObject();
if (o instanceof String) {
fos = new FileOutputStream(new File("/home/reza/Desktop/reza"));
} else {
throwException("Something is wrong");
}
Integer bytesRead = 0;
do {
o = ois.readObject();
if (!(o instanceof Integer)) {
throwException("Something is wrong");
}
bytesRead = (Integer)o;
o = ois.readObject();
if (!(o instanceof byte[])) {
throwException("Something is wrong");
}
buffer = (byte[])o;
fos.write(buffer, 0, bytesRead);
} while (bytesRead == BUFFER_SIZE);
System.out.println("File transfer success");
fos.close();
ois.close();
oos.close();
}
public static void throwException(String message) throws Exception {
throw new Exception(message);
}
public static void main(String[] args) {
new Server().start();
}
}

Answer 1

public class Server extends Thread {
public void run() {
try {
ServerSocket serverSocket = new ServerSocket(PORT);
while (true) {
Socket s = serverSocket.accept();
new ServerWorker(s).start();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
public class ServerWorker extends Thread {
private Socket _socket;
public ServerWorker(Socket socket) {
this._socket = socket;
}
public void run() {
saveFile(this._socket);
// Thread should terminate when run returns.
}
private void saveFile(Socket socket) throws Exception {
...
}
}