Question

Write a java program that can create, read, and append a file. Assume that all data written to the file are string type. One driver class and a class that contains the methods.

The program should have three methods as follows:

CreateFile - only creating a file. Once it create a file successfully, it notifies to the user that it creates a file successfully.

ReadingFile - It reads a contents of the file. This method only allow to read a string from the file.

AppendFile - It opens an existing file and append string type data to the file.

The program should ask user a file name to be create, read, and appended. The program should also ask to user whether he/she wants to do other options.

Sample Output:

Do you want to work with file? (0 for yes, 1 for no): 0
What do you want to do?
0 for create a file
1 for Read a file
2 for Writing to a file
--> 0

Enter a file name: example.txt
example.txt file is successfully created!
Do you want to do more? (1 for yes, 0 for no): 1
What do you want to do?
0 for create a file
1 for Read a file
2 for Writing to a file
--> 2

Enter a file name: example.txt
Enter letters only: This is example...
More Input? (0 to continue, -1 to end): 0
Enter letters only: This is EX000 class... Bye!
More Input? (0 to continue, -1 to end): -1
Do you want to do more? (1 for yes, 0 for no): 1
What do you want to do?
0 for create a file
1 for Read a file
2 for Writing to a file
--> 1

Enter a file name: example.txt
This is example...
This is EX000 class... Bye!
Do you want to do more? (1 for yes, 0 for no): 0

Answer 1

import java.util.Scanner;
import java.io.File;
import java.io.IOException;
import java.io.FileWriter;
class FileHandler
{
public void CreateFile(String fName) throws Exception
{
File f = new File(fName);
if (f.createNewFile())
{
System.out.println(f.getName()+" file is successfully created!");
}
else
{
System.out.println(f.getName()+" file already exists.");
}
}
public void ReadingFile(String fName) throws Exception
{

File f = new File(fName);
Scanner sc = new Scanner(f);
while (sc.hasNextLine())
{
String data = sc.nextLine();
System.out.println(data);
}
sc.close();
}
public void AppendFile(String fName) throws Exception
{
int choice;
Scanner sc = new Scanner(System.in);
FileWriter f = new FileWriter(fName);
do
{
System.out.print("Enter letters only: ");
f.write(sc.nextLine()+"\n");
System.out.print("More Input? (0 to continue, -1 to end): ");
choice = sc.nextInt();
sc.nextLine();
}while(choice==0);   
f.close();
}
}
public class Main
{
   public static void main(String[] args) throws Exception
   {
   FileHandler fh = new FileHandler();
   Scanner sc = new Scanner(System.in);
       System.out.print("Do you want to work with file? (0 for yes, 1 for no): ");
       int choice=sc.nextInt();
       if(choice==0)
       {
       do
       {
       System.out.print("What do you want to do?\n0 for create a file\n1 for Read a file\n2 for Writing to a file\n");
       int fChoice=sc.nextInt();
       System.out.print("Enter a file name: ");
       String fName= sc.next();
       if(fChoice==0)
       {
       fh.CreateFile(fName);
       }
       else if(fChoice==1)
       {
       fh.ReadingFile(fName);
       }
       else if(fChoice==2)
       {
       fh.AppendFile(fName);
       }
       else
       {
      
       }
       System.out.print("Do you want to do more? (1 for yes, 0 for no): ");
       choice=sc.nextInt();      
       }while(choice==1);
       }
   }
}