Download Files

File Tutorial
AP Computer Science
2005-2006
Create the above JFrame GUI with a JTextArea, two JLabels, and 2 JButtons.
This program will write a text file to disk, read a text file from disk, and display the
contents of the file. The file can also be viewed or written with Notepad or any word
processor using a .txt extension.
Note the \\ in the filenames. Recall \ is the "escape" character (\n, \t, etc.). The sequence \\
is needed to indicate you are not using an escape sequence.
If you just enter a filename instead of an absolute pathname, the file is written to the
current directory (i.e., your NetBeans project directory).
I also write setLocationRelativeTo(null); after initComponents( ); in the GUI constructor.
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private void jOpenButtonActionPerformed(java.awt.event.ActionEvent evt) {
String fileName = "C:\\Documents and Settings\\Curt\\
My Documents\\School\\2005-2006 courses\\Java\\myText.txt" ;
String line;
String output = "";
Scanner input;
try
{
input = new Scanner(new File( fileName ));
do
{
line = input.nextLine( );
output += line + "\n";
} while ( input.hasNext( ) );
jInputTextArea.setText(output);
input.close();
}
catch ( IOException iox )
{
System.out.println("Problem reading " + fileName );
}
}
private void jSaveButtonActionPerformed(java.awt.event.ActionEvent evt) {
String input = jInputTextArea.getText( );
String fileName = "C:\\Documents and Settings\\Curt\\
My Documents\\School\\2005-2006 courses\\Java\\myText.txt";
try
{
FileWriter writer = new FileWriter( fileName );
writer.write( input );
jInputTextArea.setText("");
writer.close();
}
catch ( IOException iox )
{
System.out.println("Problem writing " + fileName );
}
}
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Using JFileChooser
To open and save files without hard-coding the file name or asking the user to enter the
name, use JFileChooser. The program below write, reads, and displays text files using
JFileChoosers to select the files.
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private void jOpenButtonActionPerformed(java.awt.event.ActionEvent evt) {
JFileChooser fileChooser = new JFileChooser( );
int result = fileChooser.showOpenDialog( this );
if( result == JFileChooser.CANCEL_OPTION)
return;
File fileName = fileChooser.getSelectedFile( );
String line;
String output = "";
Scanner input;
try
{
input = new Scanner(new File( fileName.getCanonicalPath( ) ));
do
{
line = input.nextLine( );
output += line + "\n";
} while ( input.hasNext( ) );
jTextArea.setText(output);
input.close();
}
catch ( IOException iox )
{
System.out.println("Problem reading " + fileName );
}
}
private void jSaveButtonActionPerformed(java.awt.event.ActionEvent evt) {
String input = jTextArea.getText( );
JFileChooser fileChooser = new JFileChooser( );
int result = fileChooser.showSaveDialog( this );
if( result == JFileChooser.CANCEL_OPTION)
return;
File fileName = fileChooser.getSelectedFile( );
PrintWriter outFile;
try
{
outFile = new PrintWriter(new FileWriter(fileName));
}
catch (IOException e)
{
return;
}
outFile.print(input);
outFile.close( );
}
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/*
* GiftListGUI.java
*
* Created on November 12, 2005, 4:14 PM
*/
package GiftList;
import
import
import
import
javax.swing.*;
java.awt.*;
java.util.*;
java.io.*;
/**
*
* @author Curtis Watson
*/
public class GiftListGUI extends javax.swing.JFrame {
ArrayList list = new ArrayList(100);
/** Creates new form GiftListGUI */
public GiftListGUI() {
initComponents();
jDeletePanel.setVisible(false);
jAddPanel.setVisible(false);
setLocationRelativeTo(null);
}
/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
*/
// <editor-fold defaultstate="collapsed" desc=" Generated Code ">
private void initComponents() {
buttonGroup1 = new javax.swing.ButtonGroup();
jTabbedPane1 = new javax.swing.JTabbedPane();
jMenuPanel = new javax.swing.JPanel();
jLabel1 = new javax.swing.JLabel();
jCreatePanel = new javax.swing.JPanel();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
jFirstNameField = new javax.swing.JTextField();
jLastNameField = new javax.swing.JTextField();
jGiftRequestedField = new javax.swing.JTextField();
jCreateButton = new javax.swing.JButton();
jViewPanel = new javax.swing.JPanel();
jListArea = new javax.swing.JTextArea();
jViewButton = new javax.swing.JButton();
jPrintButton = new javax.swing.JButton();
jEditPanel = new javax.swing.JPanel();
jRadioPanel = new javax.swing.JPanel();
jDeleteRadio = new javax.swing.JRadioButton();
jModifyRadio = new javax.swing.JRadioButton();
jAddRadio = new javax.swing.JRadioButton();
jDeletePanel = new javax.swing.JPanel();
jLabel5 = new javax.swing.JLabel();
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jIDtoDeleteField = new javax.swing.JTextField();
jDeleteButton = new javax.swing.JButton();
jAddPanel = new javax.swing.JPanel();
jLabel6 = new javax.swing.JLabel();
jLabel7 = new javax.swing.JLabel();
jLabel8 = new javax.swing.JLabel();
jNameFirstField = new javax.swing.JTextField();
jNameSecondField = new javax.swing.JTextField();
jRequestedGiftField = new javax.swing.JTextField();
jUpdateButton = new javax.swing.JButton();
jScrollPane1 = new javax.swing.JScrollPane();
jDisplayArea = new javax.swing.JTextArea();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jTabbedPane1.setMinimumSize(new java.awt.Dimension(340, 565));
jTabbedPane1.setPreferredSize(new java.awt.Dimension(340, 565));
jMenuPanel.setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());
jMenuPanel.setMinimumSize(new java.awt.Dimension(338, 566));
jMenuPanel.setPreferredSize(new java.awt.Dimension(338, 566));
jLabel1.setIcon(new
javax.swing.ImageIcon("C:\\JavaPrograms\\FileExample\\opusSanta.jpg"));
jLabel1.setMaximumSize(new java.awt.Dimension(338, 566));
jLabel1.setMinimumSize(new java.awt.Dimension(338, 566));
jLabel1.setOpaque(true);
jLabel1.setPreferredSize(new java.awt.Dimension(338, 565));
jMenuPanel.add(jLabel1, new
org.netbeans.lib.awtextra.AbsoluteConstraints(0, 0, -1, -1));
jTabbedPane1.addTab("Gift List Home", jMenuPanel);
jCreatePanel.setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());
jLabel2.setText("First Name");
jCreatePanel.add(jLabel2, new
org.netbeans.lib.awtextra.AbsoluteConstraints(30, 50, -1, -1));
jLabel3.setText("Last Name");
jCreatePanel.add(jLabel3, new
org.netbeans.lib.awtextra.AbsoluteConstraints(30, 100, -1, -1));
jLabel4.setText("Gift Requested");
jCreatePanel.add(jLabel4, new
org.netbeans.lib.awtextra.AbsoluteConstraints(30, 150, -1, -1));
jCreatePanel.add(jFirstNameField, new
org.netbeans.lib.awtextra.AbsoluteConstraints(140, 50, 150, -1));
jCreatePanel.add(jLastNameField, new
org.netbeans.lib.awtextra.AbsoluteConstraints(140, 100, 150, -1));
jCreatePanel.add(jGiftRequestedField, new
org.netbeans.lib.awtextra.AbsoluteConstraints(140, 150, 150, -1));
jCreateButton.setBackground(new java.awt.Color(255, 255, 255));
jCreateButton.setFont(new java.awt.Font("Tahoma", 1, 11));
jCreateButton.setForeground(new java.awt.Color(255, 0, 51));
jCreateButton.setIcon(new
javax.swing.ImageIcon("C:\\JavaPrograms\\FileExample\\xmasTree.jpg"));
jCreateButton.setText("Click to Add Recipient to List");
jCreateButton.setHorizontalTextPosition(javax.swing.SwingConstants.CENTER);
jCreateButton.setIconTextGap(0);
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jCreateButton.setVerticalAlignment(javax.swing.SwingConstants.BOTTOM);
jCreateButton.setVerticalTextPosition(javax.swing.SwingConstants.BOTTOM);
jCreateButton.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jCreateButtonActionPerformed(evt);
}
});
jCreatePanel.add(jCreateButton, new
org.netbeans.lib.awtextra.AbsoluteConstraints(20, 200, -1, -1));
jTabbedPane1.addTab("Create List", jCreatePanel);
jViewPanel.setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());
jListArea.setColumns(20);
jListArea.setRows(20);
jListArea.setMinimumSize(new java.awt.Dimension(300, 450));
jListArea.setPreferredSize(new java.awt.Dimension(300, 450));
jViewPanel.add(jListArea, new
org.netbeans.lib.awtextra.AbsoluteConstraints(20, 20, -1, -1));
jViewButton.setText("View List");
jViewButton.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jViewButtonActionPerformed(evt);
}
});
jViewPanel.add(jViewButton, new
org.netbeans.lib.awtextra.AbsoluteConstraints(20, 500, -1, -1));
jPrintButton.setText("Print List");
jPrintButton.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jPrintButtonActionPerformed(evt);
}
});
jViewPanel.add(jPrintButton, new
org.netbeans.lib.awtextra.AbsoluteConstraints(240, 500, -1, -1));
jTabbedPane1.addTab("View List", jViewPanel);
jEditPanel.setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());
jEditPanel.setMinimumSize(new java.awt.Dimension(340, 565));
jEditPanel.setPreferredSize(new java.awt.Dimension(340, 565));
jRadioPanel.setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());
jRadioPanel.setBorder(new javax.swing.border.TitledBorder("Select an
Editing Option"));
buttonGroup1.add(jDeleteRadio);
jDeleteRadio.setText("Delete a record");
jDeleteRadio.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jDeleteRadioItemStateChanged(evt);
}
});
jRadioPanel.add(jDeleteRadio, new
org.netbeans.lib.awtextra.AbsoluteConstraints(10, 30, -1, -1));
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buttonGroup1.add(jModifyRadio);
jModifyRadio.setText("Modify a record");
jModifyRadio.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jModifyRadioItemStateChanged(evt);
}
});
jRadioPanel.add(jModifyRadio, new
org.netbeans.lib.awtextra.AbsoluteConstraints(10, 60, 140, -1));
buttonGroup1.add(jAddRadio);
jAddRadio.setText("Add new record");
jAddRadio.addItemListener(new java.awt.event.ItemListener() {
public void itemStateChanged(java.awt.event.ItemEvent evt) {
jAddRadioItemStateChanged(evt);
}
});
jRadioPanel.add(jAddRadio, new
org.netbeans.lib.awtextra.AbsoluteConstraints(10, 90, -1, -1));
jEditPanel.add(jRadioPanel, new
org.netbeans.lib.awtextra.AbsoluteConstraints(20, 30, 160, 140));
jDeletePanel.setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());
jDeletePanel.setBorder(new javax.swing.border.TitledBorder("Delete
Option"));
jLabel5.setText("Enter ID to delete");
jDeletePanel.add(jLabel5, new
org.netbeans.lib.awtextra.AbsoluteConstraints(10, 30, 110, -1));
jDeletePanel.add(jIDtoDeleteField, new
org.netbeans.lib.awtextra.AbsoluteConstraints(10, 60, 30, -1));
jDeleteButton.setText("Delete");
jDeleteButton.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jDeleteButtonActionPerformed(evt);
}
});
jDeletePanel.add(jDeleteButton, new
org.netbeans.lib.awtextra.AbsoluteConstraints(10, 90, -1, -1));
jEditPanel.add(jDeletePanel, new
org.netbeans.lib.awtextra.AbsoluteConstraints(190, 30, 130, 140));
jAddPanel.setLayout(new org.netbeans.lib.awtextra.AbsoluteLayout());
jAddPanel.setBorder(new javax.swing.border.TitledBorder("Add/Modify
Option"));
jLabel6.setText("First Name");
jAddPanel.add(jLabel6, new
org.netbeans.lib.awtextra.AbsoluteConstraints(10, 30, -1, -1));
jLabel7.setText("Last Name");
jAddPanel.add(jLabel7, new
org.netbeans.lib.awtextra.AbsoluteConstraints(10, 70, -1, -1));
jLabel8.setText("Gift Requested");
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jAddPanel.add(jLabel8, new
org.netbeans.lib.awtextra.AbsoluteConstraints(10, 110, -1, -1));
jAddPanel.add(jNameFirstField, new
org.netbeans.lib.awtextra.AbsoluteConstraints(100, 30, 60, -1));
jAddPanel.add(jNameSecondField, new
org.netbeans.lib.awtextra.AbsoluteConstraints(100, 70, 60, -1));
jAddPanel.add(jRequestedGiftField, new
org.netbeans.lib.awtextra.AbsoluteConstraints(100, 110, 60, -1));
jUpdateButton.setText("Update");
jAddPanel.add(jUpdateButton, new
org.netbeans.lib.awtextra.AbsoluteConstraints(210, 20, 80, 110));
jEditPanel.add(jAddPanel, new
org.netbeans.lib.awtextra.AbsoluteConstraints(20, 200, 300, 150));
jScrollPane1.setVerticalScrollBarPolicy(javax.swing.ScrollPaneConstants.VERTICA
L_SCROLLBAR_ALWAYS);
jScrollPane1.setPreferredSize(new java.awt.Dimension(300, 102));
jScrollPane1.setViewport(null);
jDisplayArea.setMinimumSize(new java.awt.Dimension(280, 100));
jDisplayArea.setPreferredSize(new java.awt.Dimension(280, 100));
jScrollPane1.setViewportView(jDisplayArea);
jEditPanel.add(jScrollPane1, new
org.netbeans.lib.awtextra.AbsoluteConstraints(20, 390, -1, 120));
jTabbedPane1.addTab("Edit List", jEditPanel);
getContentPane().add(jTabbedPane1, java.awt.BorderLayout.CENTER);
pack();
}
// </editor-fold>
private void jAddRadioItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
displayList( );
if(jAddRadio.isSelected( ))
{
jAddPanel.setVisible(true);
myAddMethod( );
}
else
{
jAddPanel.setVisible(false);
}
}
private void jModifyRadioItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
displayList( );
if(jModifyRadio.isSelected( ))
{
jAddPanel.setVisible(true);
myModifyMethod( );
}
else
{
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jAddPanel.setVisible(false);
}
}
private void jDeleteButtonActionPerformed(java.awt.event.ActionEvent evt) {
myDeleteMethod( );
//jIDtoDeleteField.setText("");
}
private void jDeleteRadioItemStateChanged(java.awt.event.ItemEvent evt) {
// TODO add your handling code here:
displayList( );
if(jDeleteRadio.isSelected( ))
{
jDeletePanel.setVisible(true);
}
else
{
jDeletePanel.setVisible(false);
}
}
private void myDeleteMethod( )
{
readList( );
displayList( );
int item = Integer.parseInt(jIDtoDeleteField.getText( ));
for(int i = 0; i < list.size( ); i++)
{
}
}
private void myAddMethod( )
{
}
private void myModifyMethod( )
{
}
private void readList( )
{
String fileName = "C:\\JavaPrograms\\FileExample\\gifts.txt" ;
String line;
String output = "";
Scanner input;
try
{
input = new Scanner(new File( fileName ));
do
{
line = input.nextLine( );
list.add(line);
output += line + "\n";
} while ( input.hasNextLine( ) );
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jDisplayArea.setText(output);
input.close();
}
catch ( IOException iox )
{
System.out.println("Problem reading " + fileName );
}
}
private void writeList( )
{
File fileName = new File("C:\\JavaPrograms\\FileExample\\gifts.txt");
PrintWriter outFile;
try
{
outFile = new PrintWriter(new FileWriter(fileName, true));
}
catch (IOException e)
{
System.out.println("Error writing");
return;
}
for(int j = 0; j < list.size( ); j++)
{
outFile.println(list.get(j));
}
outFile.flush( );
outFile.close( );
}
private void displayList( )
{
readList( );
jDisplayArea.setText("");
for(int k = 0; k < list.size( ); k++)
{
jDisplayArea.append((String)list.get(k) + "\n");
}
}
private void jViewButtonActionPerformed(java.awt.event.ActionEvent evt) {
String fileName = "C:\\JavaPrograms\\FileExample\\gifts.txt" ;
String line;
String output = "";
Scanner input;
jListArea.setText("");
try
{
input = new Scanner(new File( fileName ));
do
{
line = input.nextLine( );
output += line + "\n";
} while ( input.hasNextLine( ) );
jListArea.setText(output);
input.close();
}
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catch ( IOException iox )
{
System.out.println("Problem reading " + fileName );
}
}
private void jPrintButtonActionPerformed(java.awt.event.ActionEvent evt) {
PrintUtilities.printComponent(this);
}
private void jCreateButtonActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
String fname = jFirstNameField.getText( );
String lname = jLastNameField.getText( );
String gift = jGiftRequestedField.getText( );
File fileName = new File("C:\\JavaPrograms\\FileExample\\gifts.txt");
PrintWriter outFile;
try
{
outFile = new PrintWriter(new FileWriter(fileName, true));
}
catch (IOException e)
{
System.out.println("Error writing");
return;
}
Recipient r = new Recipient(fname, lname, gift);
outFile.println(r);
outFile.flush( );
outFile.close( );
jFirstNameField.setText("");
jLastNameField.setText("");
jGiftRequestedField.setText("");
jFirstNameField.requestFocus( );
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new GiftListGUI().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.ButtonGroup buttonGroup1;
private javax.swing.JPanel jAddPanel;
private javax.swing.JRadioButton jAddRadio;
private javax.swing.JButton jCreateButton;
private javax.swing.JPanel jCreatePanel;
private javax.swing.JButton jDeleteButton;
private javax.swing.JPanel jDeletePanel;
private javax.swing.JRadioButton jDeleteRadio;
private javax.swing.JTextArea jDisplayArea;
private javax.swing.JPanel jEditPanel;
private javax.swing.JTextField jFirstNameField;
private javax.swing.JTextField jGiftRequestedField;
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private javax.swing.JTextField jIDtoDeleteField;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JLabel jLabel5;
private javax.swing.JLabel jLabel6;
private javax.swing.JLabel jLabel7;
private javax.swing.JLabel jLabel8;
private javax.swing.JTextField jLastNameField;
private javax.swing.JTextArea jListArea;
private javax.swing.JPanel jMenuPanel;
private javax.swing.JRadioButton jModifyRadio;
private javax.swing.JTextField jNameFirstField;
private javax.swing.JTextField jNameSecondField;
private javax.swing.JButton jPrintButton;
private javax.swing.JPanel jRadioPanel;
private javax.swing.JTextField jRequestedGiftField;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTabbedPane jTabbedPane1;
private javax.swing.JButton jUpdateButton;
private javax.swing.JButton jViewButton;
private javax.swing.JPanel jViewPanel;
// End of variables declaration
}
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