How to open a file in a JTextArea

Question

hi..
m having difficulty in opening a file in a textarea..if anyone could help me out..
Parul

Answer 1

I hope the code below will solve ur problem,Parul --------
This program lets the user edit short text files in a window. A "File"
menu provides the following commands:
New -- Clears all text from the window.
Open -- Let's the user select a file and loads up to 100
lines of text form that file into the window. The
previous contents of the window are lost.
Save -- Let's the user specify an ouput file and saves
the contents of the window in that file.
Quit -- Closes the window and ends the program.
This class uses the non-standard class TextReader.
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class TrivialEdit extends JFrame {
public static void main(String[] args) {
// The main program just opens a window belonging to this
// TrivialEdit class. Then the window takes care of itself
// until the program is ended with the Quit command or
// when the user closes the window.
new TrivialEdit();
private JTextArea text; // Holds the text that is displayed in the window.
public TrivialEdit() {
// Add a menu bar and a JTextArea to the window, and show it
// on the screen. The first line of this routine calls the
// constructor from the superclass to specify a title for the
// window. The pack() command sets the size of the window to
// be just large enough to hold its contents.
super("A Trivial Editor");
setJMenuBar(makeMenus());
text = new JTextArea(25,50);
text.setBackground(Color.white);
text.setMargin( new Insets(3,5,0,0) );
JScrollPane scroller = new JScrollPane(text);
setContentPane(scroller);
setDefaultCloseOperation(EXIT_ON_CLOSE);
pack();
setLocation(50,50);
show();
private JMenuBar makeMenus() {
// Create and return a menu bar containing a single menu, the
// File menu. This menu contains four commands, and each
// command has a keyboard equivalent.
ActionListener listener = new ActionListener() {
// An object that will serve as listener for menu items.
public void actionPerformed(ActionEvent evt) {
// This will be called when the user makes a selection
// from the File menu. This routine just checks
// which command was selected and calls another
// routine to carry out the command.
String cmd = evt.getActionCommand();
if (cmd.equals("New"))
doNew();
else if (cmd.equals("Open..."))
doOpen();
else if (cmd.equals("Save..."))
doSave();
else if (cmd.equals("Quit"))
doQuit();
JMenu fileMenu = new JMenu("File");
JMenuItem newCmd = new JMenuItem("New");
newCmd.setAccelerator( KeyStroke.getKeyStroke("ctrl N") );
newCmd.addActionListener(listener);
fileMenu.add(newCmd);
JMenuItem openCmd = new JMenuItem("Open...");
openCmd.setAccelerator( KeyStroke.getKeyStroke("ctrl O") );
openCmd.addActionListener(listener);
fileMenu.add(openCmd);
JMenuItem saveCmd = new JMenuItem("Save...");
saveCmd.setAccelerator( KeyStroke.getKeyStroke("ctrl S") );
saveCmd.addActionListener(listener);
fileMenu.add(saveCmd);
JMenuItem quitCmd = new JMenuItem("Quit");
quitCmd.setAccelerator( KeyStroke.getKeyStroke("ctrl Q") );
quitCmd.addActionListener(listener);
fileMenu.add(quitCmd);
JMenuBar bar = new JMenuBar();
bar.add(fileMenu);
return bar;
} // end makeMenus()
private void doNew() {
// Carry out the "New" command from the File menu by
// by clearing all the text from the JTextArea.
text.setText("");
private void doSave() {
// Carry out the Save command by letting the user specify
// an output file and writing the text from the JTextArea
// to that file.
File file; // The file that the user wants to save.
JFileChooser fd; // File dialog that lets the user specify the file.
fd = new JFileChooser(new File("."));
fd.setDialogTitle("Save Text As...");
int action = fd.showSaveDialog(this);
if (action != JFileChooser.APPROVE_OPTION) {
// User has canceled, or an error occurred.
return;
file = fd.getSelectedFile();
if (file.exists()) {
// If file already exists, ask before replacing it.
action = JOptionPane.showConfirmDialog(this,
"Replace existing file?");
if (action != JOptionPane.YES_OPTION)
return;
try {
// Create a PrintWriter for writing to the specified
// file and write the text from the window to that stream.
PrintWriter out = new PrintWriter(new FileWriter(file));
String contents = text.getText();
out.print(contents);
if (out.checkError())
throw new IOException("Error while writing to file.");
out.close();
catch (IOException e) {
// Some error has occured while trying to write.
// Show an error message.
JOptionPane.showMessageDialog(this,
"Sorry, an error has occurred:\n" + e.getMessage());
private void doOpen() {
// Carry out the Open command by letting the user specify
// the file to be opened and reading up to 100 lines from
// that file. The text from the file replaces the text
// in the JTextArea.
File file; // The file that the user wants to open.
JFileChooser fd; // File dialog that lets the user specify the file.
fd = new JFileChooser(new File("."));
fd.setDialogTitle("Open File...");
int action = fd.showOpenDialog(this);
if (action != JFileChooser.APPROVE_OPTION) {
// User canceled the dialog, or an error occurred.
return;
file = fd.getSelectedFile();
try {
// Read lines from the file until end-of-file is detected,
// or until 100 lines have been read. The lines are added
// to the JTextArea, with a line feed after each line.
TextReader in = new TextReader(new FileReader(file));
String line;
text.setText("");
int lineCt = 0;
while (lineCt < 100 && in.peek() != '\0') {
line = in.getln();
text.append(line + '\n');
lineCt++;
if (in.eof() == false)
text.append("\n\n******* Text truncated to 100 lines! *******\n");
in.close();
catch (Exception e) {
// Some error has occured while trying to read the file.
// Show an error message.
JOptionPane.showMessageDialog(this,
"Sorry, some error occurred:\n" + e.getMessage());
private void doQuit() {
// Carry out the Quit command by exiting the program.
System.exit(0);
} // end class TrivialEdit
Amit Gupta