Without the BufferedReader, a
FileReader only has methods to read characters.
Here is a little program to read a file of character data and display it on the screen:
import java.io.*;
/**
* A program that opens a character based file,
* specified on the command line,
* and shows its contents on standard output.
*
* @author Carl Reynolds
*/
public class ShowFile {
public static void main( String args[] ) {
BufferedReader in = null;
String line;
// Make sure the number of arguments is correct
if ( args.length != 1) {
System.err.println( "Usage: ShowFile sourceFile" );
System.exit(1);
}
// Attempt to open the file for reading
try {
in = new BufferedReader( new FileReader( args[0] ) );
}
catch ( FileNotFoundException e ) {
System.err.println( "ShowFile: " + e.getMessage() );
System.exit( 1 );
}
// Read and display
try {
while ( (line = in.readLine() ) != null ) {
System.out.println( line );
}
}
catch ( IOException e ) {
System.err.println( "ShowFile: " + e.getMessage() );
System.exit( 1 );
}
finally {
// Close the file
try{
in.close();
}
catch( Exception e ) {}
}
}//main
} //ShowFile
CHAP. 5] PROGRAMMING IN JAVA 89
This program checks the command line arguments in the array of Strings called args to make sure that the
user provided a parameter for the file name.
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