File Handling in Java

Java offers all the basic functionalities in file handling, such as:

• Create
• Read
• Write
• Delete

Before you begin with any of the file handling operations, you must import the java.io.File package, and then you have to create a Java file object.

Apart from this, refer to the table below to learn all the basic Java file methods.

 

Method	Package	Description
createNewFile()	java.io.File	To create a file
read()	java.io.FileReader	To read  data from the file
delete()	java.io.File	To delete a file
write()	java.io.FileWrite	To write data in the file

With all these methods, you can perform different operations in a file using Java.

Create a file in Java

import java.io.File;

class Create {
 public static void main(String[] args) {

  // new object of the file type is created
  File file = new File("new.txt");

  try {

   // a new file will be created
   boolean value = file.createNewFile();
   if (value) {
    // if the file is created the message will pop
    System.out.println("The new file is created.");
   } else {
    //if the file is already present at the location, the method will pop
    System.out.println("The file already exists.");
   }
  } catch (Exception e) {
   e.getStackTrace();
  }
 }
}

Here in this program, if the file already exists in the directory, then you’ll get the output “The file already exists.” Otherwise, you’ll get “The new file is created.”

Read a file in Java

[adinserter block=”2″]

import java.io.FileReader;

class Read {
 public static void main(String[] args) {

  char[] array = new char[100];
  try {
   // Creates a new reader using the package FileReader
   FileReader input = new FileReader("fileinput.txt");

   // Reads the data from a file in characters.
   input.read(array);
   System.out.println("Data in the file:");
   System.out.println(array);

   // terminates the reader and process
   input.close();
  } catch (Exception e) {
   e.getStackTrace();
  }
 }
}

Here a different package is imported to read a file. The FileReader package is required instead of a File package. The system reads a file name “fileinput.txt” and stores information in a character type array in this program.

Delete a file in Java

import java.io.File;

class delete {
 public static void main(String[] args) {

  // creates a new file object
  File file = new File("file.txt");

  // to delete the file
  boolean value = file.delete();
  if (value) {
   System.out.println("The File is successfully deleted.");
  } else {
   System.out.println("Sorry! he File is not deleted");
  }
 }
}

In this program, first, a file is created, and then it is deleted. You can also delete an existing file. If the file is successfully deleted, the following message will appear “The File is successfully deleted,” whereas you’ll get “Sorry! the File is not deleted”.

Write a File in Java

[adinserter block=”2″]

import java.io.FileWriter;

class write {
 public static void main(String args[]) {

  String data = "This is the data in the output file";
  try {
   // Creates a Writer object using FileWriter package
   FileWriter outputobj = new FileWriter("Newfile.txt");

   // Writing the string in the file
   outputobj.write(data);
   System.out.println("Data is written to the file.");

   // Terminates the writer object
   outputobj.close();
  } catch (Exception e) {
   e.getStackTrace();
  }
 }
}

Here in this program, first, a write function is created using the FileWriter Package. Later the writer object is used to store the String of data in the file (Newfile.txt).

Final Notes

With all these default operations, you will find it extremely easy to handle files using Java. Besides this, you can manipulate anything in the files or can create or delete new files.