package com.nishith.java.files;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.Arrays;

public class FileExamples {

public static void main(String[] args) throws IOException {

// File helps us to create, delete, get details about a file.

File file = new File("FileName.txt");

// Check if the file exists

System.out.println(file.exists());

// If file does not exist creates it and returns true

// If file exists, returns false

System.out.println(file.createNewFile());

// Gets the full path of file

System.out.println(file.getAbsolutePath());

System.out.println(file.isFile());// true

System.out.println(file.isDirectory());// false

// Renaming a file

File fileWithNewName = new File("NewFileName.txt");

file.renameTo(fileWithNewName);

// There is no method file.renameTo("NewFileName.txt");

// A File class in Java represents a file and directory.

File directory = new File("src/com/rithus");

// prints full directory path

System.out.println(directory.getAbsolutePath());

System.out.println(directory.isDirectory());// true

File fileInDir = new File(directory, "NewFileInDirectory.txt");

// This does not create the actual file.

// Actual file is created when we invoke createNewFile method

System.out.println(fileInDir.createNewFile()); // true - First Time

// Prints the files and directories present in the folder

System.out.println(Arrays.toString(directory.list()));

// Creating a directory

File newDirectory = new File("newfolder");

System.out.println(newDirectory.mkdir());// true - First Time

// Creating a file in a new directory

File notExistingDirectory = new File("notexisting");

File newFile = new File(notExistingDirectory, "newFile");

// Will throw Exception if uncommented: No such file or directory

// newFile.createNewFile();

System.out.println(newDirectory.mkdir());// true - First Time

// Implementations of Writer and Reader abstract classes help us

// to write and read (content of) files.

// Writer methods - flush, close, append (text)

// Reader methods - read, close (NO FLUSH)

// Writer implementations - FileWriter,BufferedWriter,PrintWriter

// Reader implementations - FileReader,BufferedReader

// Write a string to a file using FileWriter

// FileWriter helps to write stuff into the file

FileWriter fileWriter = new FileWriter(file);

fileWriter.write("How are you doing?");

// Always flush before close. Writing to file uses Buffering.

fileWriter.flush();

fileWriter.close();

FileReader fileReader = new FileReader(file);

char[] temp = new char[25];

// Read from file using FileReader

// fileReader reads entire file and stores it into temp

System.out.println(fileReader.read(temp));// 18 - No of characters Read

// from file

System.out.println(Arrays.toString(temp));// output below

// [H, o, w, , a, r, e, , y, o, u, , d, o, i, n, g, ?, , , , , , ,

// ]

fileReader.close();// Always close anything you opened :)

// FileWriter Constructors

// can accept file(File) or the path to file (String) as argument

// When a writer object is created, it creates the file,

// if it does not exist

FileWriter fileWriter2 = new FileWriter("FileName.txt");

fileWriter2.write("How are you doing Buddy?");

// Always flush before close. Writing to file uses Buffering.

fileWriter2.flush();

fileWriter2.close();

// FileReader Constructors

// can accept file(File) or the path to file (String) as argument

FileReader fileReader2 = new FileReader("FileName.txt");

System.out.println(fileReader2.read(temp));// 24

System.out.println(Arrays.toString(temp));// output below

// BufferedWriter Constructors only accept another Writer as argument

FileWriter fileWriter3 = new FileWriter("BufferedFileName.txt");

BufferedWriter bufferedWriter = new BufferedWriter(fileWriter3);

bufferedWriter.write("How are you doing Buddy?");

bufferedWriter.newLine();

bufferedWriter.write("I'm Doing Fine");

// Always flush before close. Writing to file uses Buffering.

bufferedWriter.flush();

bufferedWriter.close();

fileWriter3.close();

// BufferedReader helps to read the file line by line

// BufferedReader Constructors only accept another Reader as argument

FileReader fileReader3 = new FileReader("BufferedFileName.txt");

BufferedReader bufferedReader = new BufferedReader(fileReader3);

String line;

// readLine returns null when reading the file is completed.

while ((line = bufferedReader.readLine()) != null) {

System.out.println(line);

}

// PrintWriter helps writing to file in a formatted way.

// PrintWriter constructor supports varied kinds of arguments

// File

// String

// Writer

PrintWriter printWriter = new PrintWriter("PrintWriterFileName.txt");

// Other than write function you can use format, printf, print, println

// functions to write to PrintWriter file.

// writes " My Name" to the file

printWriter.format("%15s", "My Name");

printWriter.println(); // New Line

printWriter.println("Some Text");

// writes "Formatted Number : 4.50000" to the file

printWriter.printf("Formatted Number : %5.5f", 4.5);

printWriter.flush();// Always flush a writer

printWriter.close();

FileReader fileReader4 = new FileReader("PrintWriterFileName.txt");

BufferedReader bufferedReader2 = new BufferedReader(fileReader4);

String line2;

// readLine returns null when reading the file is completed.

while ((line2 = bufferedReader2.readLine()) != null) {

System.out.println(line2);

}

}

}