Java Files

Java Files

Java can create, read, write, and delete files using classes from the java.io package.

Write to a file

Use FileWriter to create and write a file:

import java.io.FileWriter;

FileWriter myWriter = new FileWriter("filename.txt");
myWriter.write("Files in Java might be tricky, but it is fun enough!");
myWriter.close();

Always close() the writer to save the file.

Read a file

Use File and Scanner:

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

File myObj = new File("filename.txt");
Scanner myReader = new Scanner(myObj);
while (myReader.hasNextLine()) {
  String data = myReader.nextLine();
  System.out.println(data);
}
myReader.close();

Create a file

import java.io.File;

File myObj = new File("filename.txt");
if (myObj.createNewFile()) {
  System.out.println("File created: " + myObj.getName());
}

Delete a file

import java.io.File;

File myObj = new File("filename.txt");
if (myObj.delete()) {
  System.out.println("Deleted the file: " + myObj.getName());
}

Handling errors

File operations can throw exceptions, so wrap them in try...catch.

TL;DR

• FileWriter writes files; close it when done.
• File + Scanner reads files.
• createNewFile() and delete() manage files.
• Use try...catch for file errors.