User:Wvengen@nikhef.nl/BareBonesBrowserLaunch

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Launching a web browser from a Java application has only been introduced recently. For older versions, BareBonesBrowserLaunch has been around for a while. As a programmer, I don't want to have choose between them when the system can detect it for me. This version of BareBonesBrowserLaunch first tries the recent JDIC method, and falls back to the BareBonesBrowserLaunch method of calling the web browser manually when the former fails.

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This code compiles on java 1.5 and 1.6 (and probably lower versions as well). The nice thing is that you can compile using an older compiler and still use the newer JDesktop method when running on an new JVM. A little testing to show this:

  • Compiler 1.6 target 1.6, JVM 1.6: JDesktop method
  • Compiler 1.6 target 1.5, JVM 1.6: JDesktop method
  • Compiler 1.6 target 1.6, JVM 1.5: doesn't run: "Bad version number in .class file" (of course)
  • Compiler 1.6 target 1.5, JVM 1.5: Exec method
  • Compiler 1.5 target 1.5, JVM 1.6: JDesktop method
  • Compiler 1.5 target 1.5, JVM 1.5: Exec method

Please note that this hasn't received much testing yet, so please report your experiences.

   /////////////////////////////////////////////////////////
   //  Bare Bones Browser Launch                          //
   //  Version 1.5.99.3 (April 6, 2009)                   //
   //  By Dem Pilafian and Willem van Engen               //
   //  Supports: Mac OS X, GNU/Linux, Unix, Windows XP    //
   //  Example Usage:                                     //
   //     String url = "http://www.centerkey.com/";       //
   //     BareBonesBrowserLaunch.openURL(url);            //
   //  Public Domain Software -- Free to Use as You Like  //
   /////////////////////////////////////////////////////////
   
   import java.awt.Component;
   import java.lang.reflect.Method;
   import java.net.URI;
   import java.net.URL;
   import javax.swing.JOptionPane;
   
   /** Class to open the system's default web browser.
    * <p>
    * Until Java 1.6, there was no standard way to open an internet page with the
    * user's default web browser. This class aims to be a simple just-works solution
    * to this. It tries to use Java 1.6's method first, and falls back to running
    * an executable (which requires full system permissions, of course), which is
    * different for each platform.
    * <p>
    * This code is an adaptation of
    * <a href="http://www.centerkey.com/java/browser/">http://www.centerkey.com/java/browser/</a>
    */
   public class BareBonesBrowserLaunch {
 
       private static final String errMsg = "Error attempting to launch web browser";
  
       /** Open a URL
        * 
        * @param url {@link URL} to open
        * @param parent parent component for error message dialog
        */
       public static void openURL(URL url, Component parent) {
   	    openURL(url.toExternalForm(), parent);
       }
   
       /** Open a string URL
        * 
        * @param surl URL to open (as String)
        * @param parent parent component for error message dialog
        */
       @SuppressWarnings("unchecked") // to support older java compilers
       public static void openURL(String surl, Component parent) {
   	// Try java desktop API first (new in Java 1.6)
   	// basically: java.awt.Desktop.getDesktop().browse(new URI(url));
   	try {
   	    Class desktop = Class.forName("java.awt.Desktop");
   	    Method getDesktop = desktop.getDeclaredMethod("getDesktop", new Class[] {});
   	    Object desktopInstance = getDesktop.invoke(null, new Object[] {});
   	    Method browse = desktop.getDeclaredMethod("browse", new Class[] {URI.class});
   	    URI uri = new URI(surl);
   	    //logger.fine("Using Java Desktop API to open URL '"+url+"'");
   	    browse.invoke(desktopInstance, new Object[] {uri});
   	    return;
   	} catch(Exception e) { }
   	
   	// Failed, resort to executing the browser manually
   	String osName = System.getProperty("os.name");
   	try {
   	    // Mac OS has special Java class
   	    if (osName.startsWith("Mac OS")) {
   		Class fileMgr = Class.forName("com.apple.eio.FileManager");
   		Method openURL = fileMgr.getDeclaredMethod("openURL",
   			new Class[] {String.class});
   		//logger.fine("Using "+fileMgr+" to open URL '"+url+"'");
   		openURL.invoke(null, new Object[] {surl});
   		return;
   	    }
   	    
   	    String[] cmd = null;
   	    
   	    // Windows execs url.dll
   	    if (osName.startsWith("Windows")) {
   		cmd = new String[] { "rundll32", "url.dll,FileProtocolHandler", surl };
   		
   	    // else assume unix/linux: call one of the available browsers
   	    } else {
   		String[] browsers = {
   			// Freedesktop, http://portland.freedesktop.org/xdg-utils-1.0/xdg-open.html
   			"xdg-open",
   			// Debian
   			"sensible-browser",
   			// Otherwise call browsers directly
   			"firefox", "opera", "konqueror", "epiphany", "mozilla", "netscape" };
   		String browser = null;
   		for (int count = 0; count < browsers.length && browser == null; count++)
   		    if (Runtime.getRuntime().exec(
   			    new String[] {"which", browsers[count]}).waitFor() == 0)
   			browser = browsers[count];
   		
   		if (browser == null) {
   		    //logger.warning("No web browser found");
   		    throw new Exception("Could not find web browser");
   		}
   		
   		cmd = new String[] { browser, surl };
   	    }
   	
   	    if (Runtime.getRuntime().exec(cmd).waitFor() !=0 )
  		throw new Exception("Error opening page: "+surl);
   	}
   	catch (Exception e) {
   	    JOptionPane.showMessageDialog(parent, errMsg + ":\n" + e.getLocalizedMessage());
   	}
       }
       
       /** Open a URL
        * <p>
        * This is equal to {@link #openURL(URL, Component) openURL(url, null)}
        * so any error dialog will have no parent.
        * 
        * @param url {@link URL} to open
        */
       public static void openURL(URL url) {
   	    openURL(url, null);
       }
   
       /** Open a string URL
        * <p>
        * This is equal to {@link #openURL(String, Component) openURL(surl, null)}
        * so any error dialog will have no parent.
        * 
        * @param surl URL to open (as String)
        */
       public static void openURL(String surl) {
   	    openURL(surl, null);
       }
   }
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