27 June 2019

Java Create File Examples

development

Creating files in Java is easy. In this post, we’ll look at four different ways to create files in Java. All we need to do is import the relevant package and use relevant methods.

The examples below make use of java.io.file, java.io.fileOutputStream, and java.nio package. These classes are provided out of the box in Java API. We also look at creating a file with Apache Commons.

Create File with java.io.file class

In the first example, we will use createNewFile() method from the java.io.file class. This method returns a boolean value. It returns false if the file already exists, or true if created.

import java.io.File;
import java.io.IOException;

public class CreateFileJavaExamples {

    public static void main(String[] args) {
        File file = new File("c://examples//newFile.txt");

        try {
            if (file.createNewFile()) {
                System.out.println("File create");
            } else {
                System.out.println("File already exists!");
            }
        } catch (IOException e) {
            System.out.println(e.getMessage());
        }
    }
}

NOTE: The above example creates an empty file in the provided location.

Using java.io.fileOutputStream

The next example uses fileOutputStream. It’s important to note that this is mostly used to create a file and write content to it in one go.

import java.io.FileOutputStream;

public class CreateFileJavaExamples {

    public static void main(String[] args) {
        try {
            new FileOutputStream("newFile.txt", true);
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }
}

If the file doesn’t exist, the above method will create it. If the file exists, passing true will just append content to it.

NOTE: Be careful when using fileOutputStream. If the file exists with content, if we pass false as the parameter to the fileOutputStream method, it will overwrite the file and the content will be lost!

Create File with java.nio Package

In the following example, we will use java.nio package which was introduced in JDK 7.

In order to create a file with the nio package, we first need to set the path and then use the createFile() method from Files class. Creating files via the new nio package is the preferred option as the API is more intuitive.

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class CreateFileJavaExamples {

    public static void main(String[] args) {
        try {
            Path newFilePath = Paths.get("src/test/resources/newFile.txt");
            Files.createFile(newFilePath);
        }
        catch (IOException e) {

        }
    }
}

The above code example assumes the path src/test/resources already exists.

Apache Commons FileUtils

If you don’t want to use standard libraries provided out of the box from Java, you can use FileUtils class from Apache Commons

import org.apache.commons.io.FileUtils;
import java.io.File;
import java.io.IOException;

public class CreateFileJavaExamples {

    public static void main(String[] args) {
        File myFile = new File("src/test/resources/newFile.txt");
        
        try {
            FileUtils.touch(myFile);
        } catch (IOException e) {
            System.out.println(e.getMessage());
        }
    }
}

In the above example, we use the touch method to create a file.

27 June 2019