Programming - Writing Files

Introduction to Computer Science - Java

Writing a File

Here is a short program which writes to a file named myList.dat. This involves a three step process of creating a file handle and two objects to allow writing to the file. It will insert 5 strings into the file. It will overwrite what ever contents were previously in the file.

import javax.swing.JOptionPane;
import java.io.*;
public class Write_File
{
 public static void main( String args[] ) throws IOException
 {
  final int Max = 5;
  int counter = 0;
  String temp="";
  String file = "myList.dat";

//1. create a file handle
  FileWriter file_writer = new FileWriter ( file );

//2. open file and create an object for writing to the file
  BufferedWriter my_buffer_writer = new BufferedWriter ( file_writer );
//3. create an printing object for writing to the file
  PrintWriter outFile = new PrintWriter (my_buffer_writer);

  do 
      {
      temp=JOptionPane.showInputDialog("Enter a string to be inserted in the file.");
      outFile.println(temp);
      counter++;
      }while( counter < Max );//insert 5 strings into file

  outFile.close();//close  printing object
  JOptionPane.showMessageDialog(null, "Five strings were inserted into file " + file);
  System.exit(0);
 }//end main()
}//end class