FILE WRITER

 MAIN.JAVA:

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;







public class Main {
    public static void main(String args[]) throws IOException {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter the number of users:");
        int num = Integer.parseInt(sc.nextLine());
        ArrayList<User> al = new ArrayList<User>();
        FileWriter fw = new FileWriter("output.csv");
        BufferedWriter bw = new BufferedWriter(fw);
        for (int i = 1; i <= num; i++) {
            System.out.println("Enter the details of user :" + i);
            String record = sc.nextLine();
            String values[] = record.split(",");
            User user = new User(values[0], values[1], values[2], values[3]);
            al.add(user);
            user = null;
        }
        
        try {
            UserBO.writeFile(al, bw);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

USER.JAVA:

public class User {
    String name;
    String mobileNumber;
    String username;
    String password;
    
    public User(String name,String mobileNumber,String username,String password)
    {
        this.name=name;
        this.mobileNumber=mobileNumber;
        this.username=username;
        this.password=password;
    }

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getMobileNumber() {
		return mobileNumber;
	}

	public void setMobileNumber(String mobileNumber) {
		this.mobileNumber = mobileNumber;
	}

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}
}

USERBO.JAVA:

import java.util.*;
import java.io.*;







public class UserBO {
    public static void writeFile(ArrayList<User> userList, BufferedWriter bw) throws Exception {
        for (int i = 0; i < userList.size(); i++) {
            String rec = (userList.get(i)).getName() + "," + userList.get(i).getMobileNumber() + ","
                    + userList.get(i).getUsername() + "," + userList.get(i).getPassword() + "\n";
            bw.write(rec);
            bw.flush();
        }
        bw.close();
    }
}