/home/wpollock1/public_html/AJava/FileDemo.java

// FileDemo.java - Shows how to use java.io classes to read and
// write files.
//
// Written 2009 by Wayne Pollock, Tampa Florida
//

import java.io.*;
import javax.swing.JOptionPane;

public class FileDemo
{
   public static void main ( String [] args )
   {
      JOptionPane.showMessageDialog( null, "The system default encoding is " +
         getSystemDefaultEncoding() );
      writeFile( "lowercase-UTF8.txt" );
      readFile( "UTF-8-demo.txt" );
   }

   /**
    * Windows uses the phrase "code page" for encoding, and
    * uses a Micorsoft naming scheme.  For example "Cp1252" is
    * a code for "Windows Western Europe / Latin-1".
    *
    * A table of encodings may be found at:
    *    http://java.sun.com/j2se/1.5.0/docs/guide/intl/encoding.doc.html
    *
    * @return The value of the system property "file.encoding"
    */

   public static String getSystemDefaultEncoding ()
   {
      String encoding = System.getProperty( "file.encoding" );
      return encoding;
   }

   /** Writes all the lower case letters of the Unicode alphabet to a file.
    * The "UTF-8" encoding used has the property of representing ASCII text
    * as itself (one byte), and other characters as two or three bytes.
    *
    * @param fileName The name of the file to create.
    */

   public static void writeFile ( String fileName )
   {
      try
      {
         FileOutputStream fos = new FileOutputStream( fileName );
         OutputStreamWriter osw = new OutputStreamWriter( fos, "UTF8" );
         for ( int c = '\u0000'; c <= '\uffff'; ++c )
         {
            if ( ! Character.isLowerCase( (char)c ) )
               continue;
            osw.write( c );
         }
         osw.close();
      }
      catch ( IOException e )
      {
         System.err.println( e );
      }
   }

   /** Reads all the lower case letters from a file.
    * The "UTF-8" encoding used has the property of representing ASCII text
    * as itself (one byte), and other characters as two or three bytes.
    *
    * @param fileName The name of the file to read.
    */

   public static void readFile ( String fileName )
   {
      final int MAX = 100, EOF = -1;
      int ch;
      StringBuilder sb = new StringBuilder( MAX );
      try
      {
         FileInputStream fis = new FileInputStream( fileName );
         InputStreamReader isr = new InputStreamReader( fis, "UTF8" );
         while ( (ch = isr.read() ) != EOF )
         {
            if ( Character.isLowerCase( (char)ch ) )
               sb.append( (char) ch );
            if ( sb.length() >= MAX )
               break;
         }
         isr.close();
      }
      catch ( IOException e )
      {
         System.err.println( e );
      }

      JOptionPane.showMessageDialog( null, "First " + MAX +
         " lowercase letters found in file \"" + fileName + "\":\n" +
         sb.toString() );
   }
}