Java Write to Temporary File

Learn to create a temporary file and write to it in Java. We will use the code sample used for creating temporary file example.

1. BufferedWriter with FileWriter

FileWriter class can be used for writing character files. Wrapping a BufferedWriter around it increases the performance of the program.

Example 1: Java program to create a temporary file and write to it

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

public class TemporaryFileExample
{
   public static void main(String[] args)
   {
      File temp;
      try
      {
         temp = File.createTempFile("myTempFile", ".txt");

         BufferedWriter bw = new BufferedWriter(new FileWriter(temp));
         bw.write("This is the temporary data written to temp file");

         bw.close();
      } catch (IOException e)
      {
         e.printStackTrace();
      }
   }
}

2. Files.write() – Java NIO

The write() method does the simple thing. It writes bytes to a file. By default, if the temp file does not exist, it will create a new file else overwrites an existing file.

To append to an existing teporary file, use StandardOpenOption.APPEND option while writing the content.

Example 2: Creating a temporary file and writing to it

Due to usage of deleteOnExit(), the file will be deleted when the program exits.

public class TemporaryFileExample
{
   public static void main(String[] args)
   {
      try
      {
         final Path path = Files.createTempFile("myTempFile", ".txt");
         System.out.println("Temp file : " + path);

		 //Writing data here
		 byte[] buf = "some data".getBytes();
		 Files.write(path, buf);

		 //For appending to the existing file
		 //Files.write(path, buf, StandardOpenOption.APPEND);

         //Delete file on exit
         path.toFile().deleteOnExit();

      } catch (IOException e)
      {
         e.printStackTrace();
      }
   }
}

Happy Learning !!