Create txt file in java

Introduction to Java
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Java Create and Write To Files

To create a file in Java, you can use the createNewFile() method. This method returns a boolean value: true if the file was successfully created, and false if the file already exists. Note that the method is enclosed in a try. catch block. This is necessary because it throws an IOException if an error occurs (if the file cannot be created for some reason):

Example

import java.io.File; // Import the File class import java.io.IOException; // Import the IOException class to handle errors public class CreateFile < public static void main(String[] args) < try < File myObj = new File("filename.txt"); if (myObj.createNewFile()) < System.out.println("File created: " + myObj.getName()); >else < System.out.println("File already exists."); >> catch (IOException e) < System.out.println("An error occurred."); e.printStackTrace(); >> >

To create a file in a specific directory (requires permission), specify the path of the file and use double backslashes to escape the » \ » character (for Windows). On Mac and Linux you can just write the path, like: /Users/name/filename.txt

Example

File myObj = new File("C:\\Users\\MyName\\filename.txt");

Write To a File

In the following example, we use the FileWriter class together with its write() method to write some text to the file we created in the example above. Note that when you are done writing to the file, you should close it with the close() method:

Example

import java.io.FileWriter; // Import the FileWriter class import java.io.IOException; // Import the IOException class to handle errors public class WriteToFile < public static void main(String[] args) < try < FileWriter myWriter = new FileWriter("filename.txt"); myWriter.write("Files in Java might be tricky, but it is fun enough!"); myWriter.close(); System.out.println("Successfully wrote to the file."); >catch (IOException e) < System.out.println("An error occurred."); e.printStackTrace(); >> >

To read the file above, go to the Java Read Files chapter.

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Java create new file

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Creating a file is a very common IO operation. Today we will look into different ways to create a file in java.

Java create file

There are three popular methods to create file in java. Let’s look at them one by one.

File.createNewFile()

java.io.File class can be used to create a new File in Java. When we initialize File object, we provide the file name and then we can call createNewFile() method to create new file in Java. File createNewFile() method returns true if new file is created and false if file already exists. This method also throws java.io.IOException when it’s not able to create the file. The files created is empty and of zero bytes. When we create the File object by passing the file name, it can be with absolute path, or we can only provide the file name or we can provide the relative path. For a non-absolute path, File object tries to locate files in the project root directory. If we run the program from command line, for the non-absolute path, File object tries to locate files from the current directory. While creating the file path, we should use System property file.separator to make our program platform independent. Let’s see different scenarios with a simple java program to create a new file in java.

package com.journaldev.files; import java.io.File; import java.io.IOException; public class CreateNewFile < /** * This class shows how to create a File in Java * @param args * @throws IOException */ public static void main(String[] args) throws IOException < String fileSeparator = System.getProperty("file.separator"); //absolute file name with path String absoluteFilePath = fileSeparator+"Users"+fileSeparator+"pankaj"+fileSeparator+"file.txt"; File file = new File(absoluteFilePath); if(file.createNewFile())< System.out.println(absoluteFilePath+" File Created"); >else System.out.println("File "+absoluteFilePath+" already exists"); //file name only file = new File("file.txt"); if(file.createNewFile())< System.out.println("file.txt File Created in Project root directory"); >else System.out.println("File file.txt already exists in the project root directory"); //relative path String relativePath = "tmp"+fileSeparator+"file.txt"; file = new File(relativePath); if(file.createNewFile())< System.out.println(relativePath+" File Created in Project root directory"); >else System.out.println("File "+relativePath+" already exists in the project root directory"); > >

/Users/pankaj/file.txt File Created file.txt File Created in Project root directory Exception in thread "main" java.io.IOException: No such file or directory at java.io.UnixFileSystem.createFileExclusively(Native Method) at java.io.File.createNewFile(File.java:947) at com.journaldev.files.CreateNewFile.main(CreateNewFile.java:32)

For the relative path, it throws IOException because tmp directory is not present in the project root folder. So it’s clear that createNewFile() just tries to create the file and any directory either absolute or relative should be present already, else it throws IOException . So I created “tmp” directory in the project root and executed the program again, here is the output.

File /Users/pankaj/file.txt already exists File file.txt already exists in the project root directory tmp/file.txt File Created in Project root directory

First two files were already present, so createNewFile() returns false , third file was created in tmp directory and returns true. Any subsequent execution results in the following output:

File /Users/pankaj/file.txt already exists File file.txt already exists in the project root directory File tmp/file.txt already exists in the project root directory

//first execution from classes output directory pankaj:~/CODE/JavaFiles/bin$ java com/journaldev/files/CreateNewFile File /Users/pankaj/file.txt already exists file.txt File Created in Project root directory Exception in thread "main" java.io.IOException: No such file or directory at java.io.UnixFileSystem.createFileExclusively(Native Method) at java.io.File.createNewFile(File.java:947) at com.journaldev.files.CreateNewFile.main(CreateNewFile.java:32) //tmp directory doesn't exist, let's create it pankaj:~/CODE/JavaFiles/bin$ mkdir tmp //second time execution pankaj:~/CODE/JavaFiles/bin$ java com/journaldev/files/CreateNewFile File /Users/pankaj/file.txt already exists File file.txt already exists in the project root directory tmp/file.txt File Created in Project root directory //third and subsequent execution pankaj:~/CODE/JavaFiles/bin$ java com/journaldev/files/CreateNewFile File /Users/pankaj/file.txt already exists File file.txt already exists in project root directory File tmp/file.txt already exists in project root directory

FileOutputStream.write(byte[] b)

If you want to create a new file and at the same time write some data into it, you can use FileOutputStream write method. Below is a simple code snippet to show it’s usage. The rules for absolute path and relative path discussed above is applicable in this case too.

String fileData = "Pankaj Kumar"; FileOutputStream fos = new FileOutputStream("name.txt"); fos.write(fileData.getBytes()); fos.flush(); fos.close();

Java NIO Files.write()

We can use Java NIO Files class to create a new file and write some data into it. This is a good option because we don’t have to worry about closing IO resources.

String fileData = "Pankaj Kumar"; Files.write(Paths.get("name.txt"), fileData.getBytes());

That’s all for creating a new file in the java program.

You can checkout more core java examples from our GitHub Repository.

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