Source of FileClassDemo.java


  1: //FileClassDemo.java
  2: 
  3: import java.util.Scanner;
  4: import java.io.File;
  5: import java.io.FileNotFoundException;
  6: 
  7: public class FileClassDemo
  8: {
  9:     public static void main(String[] args)
 10:     {
 11:         System.out.print("Enter file name: ");
 12:         Scanner keyboard = new Scanner(System.in);
 13:         String fileName = keyboard.next();
 14: 
 15:         File fileObject = new File(fileName);
 16:         boolean fileOK = false;
 17:         while (!fileOK)
 18:         {
 19:             if (!fileObject.exists())
 20:                 System.out.println("No such file");
 21:             else if (!fileObject.canRead())
 22:                 System.out.println("That file is not readable.");
 23:             else
 24:                 fileOK = true;
 25: 
 26:             if (!fileOK)
 27:             {
 28:                 System.out.println("Enter file name again:");
 29:                 fileName = keyboard.next();
 30:                 fileObject = new File(fileName);
 31:             }
 32:         }
 33: 
 34:         Scanner inputStream = null;
 35:         System.out.println("The file " + fileName
 36:             + "\ncontains the following lines\n");
 37:         try
 38:         {
 39:             inputStream = new Scanner(new File(fileName));
 40:         }
 41:         catch (FileNotFoundException e)
 42:         {
 43:             System.out.println("Error opening the file " + fileName);
 44:             System.exit(0);
 45:         }
 46: 
 47:         while (inputStream.hasNextLine())
 48:         {
 49:             String line = inputStream.nextLine();
 50:             System.out.println(line);
 51:         }
 52: 
 53:         inputStream.close();
 54:     }
 55: }