Question

1) User wants to keep track Books. Each Book has Author (String), Title (String), Year (4 digit String) and Price (Double). Write a Java Book class with constructors and set/get methods.

2) Write a Java program that asks user to enter the Book data on the Console. User can enter any number of books until terminated on the Console. Write the book data to a text file called "book.txt" in the current project directory.

3) Write a Java program to read the "books.txt" file and display the book data contained in it on the Console with each field displayed in column, one line per book.

Answer 1

Book.java

public class Book {
   //private attributes
   private String author;
   private String title;
   private String year;
   private double price;

   //constructor that takes in all attributes and sets them
   public Book(String strAuthor, String strTitle, String strYear, double dblPrice)
   {
       author = strAuthor;
       title = strTitle;
       year = strYear;
       price = dblPrice;
   }

   //getter methods
   //method that returns author
   public String getAuthor()
   {
       return author;
   }

   //method that returns title
   public String getTitle()
   {
       return title;
   }

   //method that returns year
   public String getYear()
   {
       return year;
   }

   //method that returns price
   public double getPrice()
   {
       return price;
   }

   //setter methods
   //method that sets author name
   public void setAuthor(String strAuthor)
   {
       author = strAuthor;
   }

   //method that sets title of the book
   public void setTitle(String strTitle)
   {
       title = strTitle;
   }

   //method that sets year
   public void setYear(String strYear)
   {
       year = strYear;
   }

   //method that sets price of the book
   private void setPrice(double dblPrice)
   {
       price = dblPrice;
   }

   //override toString method
   public String toString()
   {
       return getAuthor() + "\t\t" + getTitle() + "\t\t" + getYear() + "\t\t$" + getPrice();
   }
}

EnterBookData.java

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

public class EnterBookData {

   public static void main(String[] args) throws IOException {
       //create object to the Scanner class
       Scanner input = new Scanner(System.in);
      
       boolean repeat = true;
       String author, title, year;
       double price;
       String userChoice;
      
       // open the file to write book data
        FileWriter fw = new FileWriter("book.txt");
        BufferedWriter bw = new BufferedWriter(fw);
      
        //repeat a loop to read book details
       while(repeat)
       {
           //prompt and read author name
           System.out.print("Enter the name of the Author: " );
           author = input.nextLine();
           //prompt and read book title
           System.out.print("Enter the title of the book: ");
           title = input.nextLine();
           //prompt and read year of publishing
           System.out.print("Enter the year of publishing: ");
           year = input.nextLine();
           //prompt and read price
           System.out.print("Enter the price: $");
           price = input.nextDouble();
          
           //create a book object
           Book bookObj = new Book(author, title, year, price);
           //write book details to text file
           //as author names and title contain spaces we are here writing each detail in a separate line
           bw.write(bookObj.getAuthor() + "\n");
           bw.write(bookObj.getTitle() + "\n");
           bw.write(bookObj.getYear() + "\n");
           bw.write(bookObj.getPrice() + "\n");
          
           //prompt and read if user wants to enter one more book detail
           System.out.print("Do you want to enter another book details (y/n)? ");
           input.nextLine();
           userChoice = input.nextLine();
           //terminate the loop if the user wants to exit
           if(userChoice.equals("n") || userChoice.equals("N"))
               repeat = false;
       }
       //close the writers
       bw.close();
       fw.close();
       input.close();
   }

}

DisplayBookData.java

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class DisplayBookData {

   public static void main(String[] args) throws FileNotFoundException {
       // pass the path to the file as a parameter
       File file = new File("book.txt");
       Scanner input = new Scanner(file);
       String author = "", title = "", year = "";
       double price = 0.0;
       //display the header
       System.out.println("Author\t\tTitle\t\t\t\tYear\t\tPrice");
       //run a loop until the end of the file is reached
       while (input.hasNextLine())
       {
           //read author name
           author = input.nextLine();
           //read title
           title = input.nextLine();
           //read year
           year = input.nextLine();
           //read price
           price = Double.parseDouble(input.nextLine());
           //create a Book object
           Book bookObj = new Book(author, title, year, price);
           //display the book details
           System.out.println(bookObj.toString());
       }   

       input.close();
   }

}

Output

Program Screenshots

File generated