Answers by Sentry

How to create a file and write to it in Java

Gareth D.

The Problem

How do I create a file and write to it in Java?

The Solution

There are many different ways to write data to a file in Java, but the easiest way is to use a BufferedWriter along with a FileWriter, as follows.

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class Main {

    public static void main(String[] args) {
        String stringToWrite = "Java files are easy";
        try {
            BufferedWriter writer = new BufferedWriter(new FileWriter("newfile.txt"));
            writer.write(stringToWrite);
            writer.close();
        } catch (IOException ioe) {
            System.out.println("Couldn't write to file");
        }
    }
}

This will write “Java files are easy” to a file called newfile.txt in the same directory as your Main.java file. If the file already exists, it will be overwritten.

If you want to append data to an existing file, you can pass true as a second argument to FileWriter. This enables append mode, so the file will not be overwritten.

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class Main {

    public static void main(String[]args) {
        String stringToWrite = "\nJava files are easy";
        try {
            BufferedWriter writer = new BufferedWriter(new FileWriter("newfile.txt", true));
            writer.write(stringToWrite);

            writer.close();
        } catch (IOException ioe) {
            System.out.println("Couldn't write to file");
        }
    }
}

The code above will append a new line saying “Java files are easy” to the newfile.txt each time it is run.

Further reading

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