Java Tutorial/Development/JNLP
An Example JNLP File
<source lang="java">
<?xml version="1.0" encoding="utf-8"?>
<jnlp spec="1.0" codebase="http://localhost/jws" href="Notepad.jnlp">
<information>
<title>Notepad Demo</title>
<vendor>Sun Microsystems, Inc.</vendor>
</information>
<resources>
<property name="jnlp.publish-url" value="$$context/publish"/>
<j2se version="1.3+" href="http://java.sun.ru/products/autodl/j2se"/>
<jar href="Notepad.jar"/>
</resources>
<application-desc main-class="Notepad"/>
</jnlp> File: index.html <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <HEAD>
<TITLE>Java Web Start Demo</TTLE>
</HEAD> <BODY>
Java Web Start Demo
This link is to the Notepad.jnlp file. </BODY> </HTML></source>
Uses the JNLP API to open and save files
<source lang="java">
/*
*
* Copyright (c) 1998 Sun Microsystems, Inc. All Rights Reserved.
*
* Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
* modify and redistribute this software in source and binary code form,
* provided that i) this copyright notice and license appear on all copies of
* the software; and ii) Licensee does not utilize the software in a manner
* which is disparaging to Sun.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
* IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
* NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
* LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
* LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
* INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
* CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
* OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* This software is not designed or intended for use in on-line control of
* aircraft, air traffic, aircraft navigation or aircraft communications; or in
* the design, construction, operation or maintenance of any nuclear
* facility. Licensee represents and warrants that it will not use or
* redistribute the Software for such purposes.
*/
import java.io.*; import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.filechooser.*; import javax.jnlp.*; public class JWSFileChooserDemo extends JPanel
implements ActionListener {
static private final String newline = "\n";
JButton openButton, saveButton;
JTextArea log;
public JWSFileChooserDemo() {
super(new BorderLayout());
//Create the log first, because the action listeners
//need to refer to it.
log = new JTextArea(5,20);
log.setMargin(new Insets(5,5,5,5));
log.setEditable(false);
JScrollPane logScrollPane = new JScrollPane(log);
//Create the open button. We use the image from the JLF
//Graphics Repository (but we extracted it from the jar).
openButton = new JButton("Open a File...",
createImageIcon("images/Open16.gif"));
openButton.addActionListener(this);
//Create the save button. We use the image from the JLF
//Graphics Repository (but we extracted it from the jar).
saveButton = new JButton("Save a File...",
createImageIcon("images/Save16.gif"));
//PENDING: removed the Save button action listener
//so that people won"t overwrite existing files.
//See bug 4761577.
//saveButton.addActionListener(this);
saveButton.setEnabled(false);
//For layout purposes, put the buttons in a separate panel
JPanel buttonPanel = new JPanel();
buttonPanel.add(openButton);
buttonPanel.add(saveButton);
//Add the buttons and the log to this panel.
add(buttonPanel, BorderLayout.PAGE_START);
add(logScrollPane, BorderLayout.CENTER);
}
public void actionPerformed(ActionEvent e) {
//Handle open button action.
if (e.getSource() == openButton) {
FileOpenService fos = null;
FileContents fileContents = null;
try {
fos = (FileOpenService)ServiceManager.
lookup("javax.jnlp.FileOpenService");
} catch (UnavailableServiceException exc) { }
if (fos != null) {
try {
fileContents = fos.openFileDialog(null, null);
} catch (Exception exc) {
log.append("Open command failed: "
+ exc.getLocalizedMessage()
+ newline);
log.setCaretPosition(log.getDocument().getLength());
}
}
if (fileContents != null) {
try {
//This is where a real application would do something
//with the file.
log.append("Opened file: " + fileContents.getName()
+ "." + newline);
} catch (IOException exc) {
log.append("Problem opening file: "
+ exc.getLocalizedMessage()
+ newline);
}
} else {
log.append("User canceled open request." + newline);
}
log.setCaretPosition(log.getDocument().getLength());
}
//Handle save button action.
if (e.getSource() == saveButton) {
FileSaveService fss = null;
FileContents fileContents = null;
ByteArrayInputStream is = new ByteArrayInputStream(
(new String("Saved by JWSFileChooserDemo").getBytes()));
//XXX YIKES! If they select an
//XXX existing file, this will
//XXX overwrite that file.
try {
fss = (FileSaveService)ServiceManager.
lookup("javax.jnlp.FileSaveService");
} catch (UnavailableServiceException exc) { }
if (fss != null) {
try {
fileContents = fss.saveFileDialog(null,
null,
is,
"JWSFileChooserDemo.txt");
} catch (Exception exc) {
log.append("Save command failed: "
+ exc.getLocalizedMessage()
+ newline);
log.setCaretPosition(log.getDocument().getLength());
}
}
if (fileContents != null) {
try {
log.append("Saved file: " + fileContents.getName()
+ "." + newline);
} catch (IOException exc) {
log.append("Problem saving file: "
+ exc.getLocalizedMessage()
+ newline);
}
} else {
log.append("User canceled save request." + newline);
}
log.setCaretPosition(log.getDocument().getLength());
}
}
/** Returns an ImageIcon, or null if the path was invalid. */
protected static ImageIcon createImageIcon(String path) {
java.net.URL imgURL = JWSFileChooserDemo.class.getResource(path);
if (imgURL != null) {
return new ImageIcon(imgURL);
} else {
System.err.println("Couldn"t find file: " + path);
return null;
}
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("JWSFileChooserDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Create and set up the content pane.
JComponent newContentPane = new JWSFileChooserDemo();
newContentPane.setOpaque(true); //content panes must be opaque
frame.setContentPane(newContentPane);
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application"s GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}</source>
