File Input/Output

Here is some Java code that can be re-used so that you don't have to re-type this all the time:

The following code reads a file line by line. It does other cool stuff too.

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileOutputStream;
import java.io.File;
import java.io.PrintStream;

import javax.swing.JFileChooser;
import javax.swing.ProgressMonitor;
import javax.swing.filechooser.FileSystemView;

public class FileInput {

    /**
     * @param args
     */
    public static void main(String[] args) {

        //redirect the output and error stream to a file.
        //This is useful when working Swing apps that don't show a console.
        try {
            System.setOut(new PrintStream(
              new FileOutputStream("FileInput_output.txt", false)));
            System.setErr(new PrintStream(
              new FileOutputStream("FileInput_log.txt", false)));
        }
        catch( FileNotFoundException fnfe ) {
            System.err.println("Error setting output stream to log files");
            fnfe.printStackTrace();
        }

        //add a file chooser to allow choosing a diretory of where a set
        //of files to input are
        JFileChooser chooser = new JFileChooser();
        chooser.setDialogTitle("Specify the location of input files");

        //set mode to only view and choose directories
        chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);

        int returnVal = chooser.showOpenDialog(null);
        if(returnVal == JFileChooser.APPROVE_OPTION) {

            //get all files in the chosen directory
            FileSystemView fsv=FileSystemView.getFileSystemView();
            File[] files = fsv.getFiles(chooser.getSelectedFile(), true);

            try {
                //to make it cool, we'll add a progress monitor to show what 
                //file the system is processing
                ProgressMonitor progressBar = new ProgressMonitor(
                                                        null, 
                                                        "FileInput Progress", 
                                                        "", 
                                                        0, 
                                                        files.length);

                for(int i=0; i
                    progressBar.setProgress(i);
                    progressBar.setNote("Processing file: " +
                       files[i].getName());

                    //read the file
                    BufferedReader in = new BufferedReader(
                      new FileReader(files[i]));

                    String line;

                    while( (line = in.readLine())!= null) {

                        //Do stuff with each line here

                    }
                    in.close();
                }

                progressBar.close();
            }
            catch( Exception e ) {
                System.err.println(e);
            }
        }
    }
}