Read word by word from file - JAVA

How to Read word by word from file in Java - File Handling in java

This program shows how to Read word by word from a file and display each word to console in Java.

Testing_.java

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

public class Testing_
{
    public static void main(String args[]) throws FileNotFoundException{
     Scanner scanner = new Scanner(new File("myFile.txt"));
     while(scanner.hasNext())System.out.print(scanner.next());//Get next Word
     scanner.close();
    }
}

Read whole file into character array in Java - File Handling - java

How to Read entire file into character array in Java - File Handling in java

FileReader's read(char []) function allows you to load entire file into the character array.

This program shows how to Read an entire file into character array in Java..

Testing_.java

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

public class Testing_
{
    public static void main(String args[]) throws FileNotFoundException{
     try {
   FileReader fileReader = new FileReader(new File("myFile.txt"));
   char [] buff = new char[1000];
   fileReader.read(buff);
   System.out.print(buff);
   fileReader.close();
  } catch (IOException e) {
   e.printStackTrace();
  }
    }
}

Input String and Write into File - JAVA

How to Input String and write to a file in Java - File Handling in java

This program shows how to input a string from user and write it into a file in Java..

Testing_.java

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

public class Testing_
{
    public static void main(String args[]) throws FileNotFoundException{
     System.out.print("Enter string to be written to file: ");
     //input
     Scanner scanner = new Scanner(System.in);
     String stringToBeWritten = scanner.nextLine();
     Formatter formatter = new Formatter("myFile.txt");
     formatter.format("THe string I want to write is: %s", stringToBeWritten);
     if (formatter!=null)
      formatter.close();
     System.out.println("Written!");
    }
}

Write to file - Java

How to Write to file in Java - File Handling in java

Main.java

import java.io.FileNotFoundException;
import java.util.Formatter;

public class Main
{
    public static void main(String args[]) throws FileNotFoundException{
     Formatter formatter = new Formatter("myFile.txt");
     formatter.format("THe string I want to write is: %s", "My String");
     if (formatter!=null)
      formatter.close();
    }
}

Read File - JAVA

How to Read file in Java - File Handling in java

To read file in Java, we use the nextLine() function of scanner to get string up til enter. And do this in loop untill end of file using hasNext().

This program shows how to Read a file in Java..

Main.java

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


public class Main {
 public static void main(String args[]){
  Scanner scanner;
  try {
   scanner = new Scanner(new File("myFile.txt"));
   
   while (scanner.hasNext()){
    System.out.println(scanner.nextLine());
   }
   
  } catch (FileNotFoundException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }  
 }
}

Serialization - JAVA

How to Read entire file into character array in Java - File Handling in java

FileReader's read(char []) function allows you to load entire file into the character array.

This program shows how to Read an entire file into character array in Java..

Student.java

public class Student implements Serializable{
 int id;
 String name;
 
 public Student(int id, String name) {
  this.id = id;
  this.name = name;
 }
 
 public Student() {
 }

 public void display(){
  System.out.println("ID: " + id);
  System.out.println("Name: " + name);
 }
}

FileIO.java

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

public class FileIO{

 public static void main(String[] args) {
  Student student = new Student(1, "Name 1");
  student.display();
  
  System.out.println("Serializing...\n");
  serialize(student);
  
  System.out.println("Deserializing and reading into new object...");
  System.out.println("Student#2 object");
  Student student2 = new Student();
  student2 = deserialize(student2);
  student2.display();
  
 }

 private static Student deserialize(Student student2) {
  ObjectInputStream objectInputStream;
  try {
   objectInputStream = new ObjectInputStream(new FileInputStream("myFile.ser"));
   student2 = (Student) objectInputStream.readObject();
   if (objectInputStream!=null)
    objectInputStream.close();
  } catch (ClassNotFoundException e) {
   e.printStackTrace();
  } catch (IOException e) {
   e.printStackTrace();
  }
  return student2;
 }

 private static void serialize(Student student) {
  //Serialize student information into file.
  ObjectOutputStream objectOutputStream;
  try {
   objectOutputStream = new ObjectOutputStream(new FileOutputStream("myFile.ser"));
   objectOutputStream.writeObject(student);
   if (objectOutputStream!=null)
    objectOutputStream.close();
  } catch (IOException e) {
   e.printStackTrace();
  }
 }

}

Writing to File in Java - File Handling in Java

How to Write to File in Java - File Handling in Java

Formatter is used to write to file.

FileIO.java

import java.io.FileNotFoundException;
import java.util.Formatter;

public class FileIO {

 public static void main(String[] args) {
  String fileName = "myFile.txt";
  Formatter formatter = null;
  try {
   formatter = new Formatter(fileName);
  } catch (FileNotFoundException e) {
   System.err.println("Error opening or creating a file");
   e.printStackTrace();
  }
  formatter.format("Content to be written to %s", fileName);
  if (formatter != null)
   formatter.close();
  System.out.println("File written!");
 }

}