How to open a URL in the default browser

If you ever wondered if there is an easy way to open a URL from your Java program in the user-default browser, with Java SE 6 there is. Unless your platform doesn't support this. The good news is that you can test if this is the case or not.

In Java SE 6 a new class has been added to the java.awt package: Desktop. This class has a public class method isDesktopSupported() which returns true if the class is supported on the current platform, and false otherwise.

If the class is supported, you can retrieve an instance using the class method getDesktop().

You can use the browse() method to display a URI in the default browser. If this browser is not able to handle the specified URI, the application registered for handling the URIs of the specified type is invoked. For example, the URI news:comp.lang.perl.misc might invoke a Usenet client.

However, before you call the browse() method make sure to check if this action is supported on the current platform by calling the isSupported() method with java.awt.Desktop.Action.BROWSE as the value of the first and only parameter.

Note that even though this method returns true, it's still possible that the platform doesn't support the URI - for example if there is no application registered for the given scheme. In this case the browse() method will throw an IOException.

Example Java program using the browse method

Below follows a small example program that can be invoked from the command line. It attempts to open each argument as a URI in the user-default browser, or if the browser can't handle the URI, an attempt is made to pass the URI to the application registered for the URI's scheme.

import java.net.URI;
import java.awt.Desktop;

public class OpenURI {

    public static void main(String [] args) {

        if( !java.awt.Desktop.isDesktopSupported() ) {

            System.err.println( "Desktop is not supported (fatal)" );
            System.exit( 1 );
        }

        if ( args.length == 0 ) {

            System.out.println( "Usage: OpenURI [URI [URI ... ]]" );
            System.exit( 0 );
        }

        java.awt.Desktop desktop = java.awt.Desktop.getDesktop();

        if( !desktop.isSupported( java.awt.Desktop.Action.BROWSE ) ) {

            System.err.println( "Desktop doesn't support the browse action (fatal)" );
            System.exit( 1 );
        }

        for ( String arg : args ) {

            try {

                java.net.URI uri = new java.net.URI( arg );
                desktop.browse( uri );
            }
            catch ( Exception e ) {

                System.err.println( e.getMessage() );
            }
        }
    }
}

But there are more actions

Besides the browse() method there are 5 more methods, providing support for the 4 following Desktop actions:

EDIT

The edit() method launches the associated editor application and opens a file for editing.

MAIL

There are two mail() methods. The first one doesn't take any parameters and launches the mail composing window of the user-default mail client. The second method takes a single parameter: a "mailto" URI. It also launces the mail composing window of the user-default mail client, but additionally fills in the message fields specified by the "mailto" URI (for example, to, subject, etc.).

OPEN

The open() method launches the associated application to open the file. If the specified file is a directory, the file manager of the current platform is launched to open it.

PRINT

Prints a file with the native desktop printing facility, using the associated application's print command.

Java 1.6 Desktop class related

• Desktop - Class documentation, Java Platform SE 6
• Desktop.Action - Enum documentation, Java Platform SE6
• Using the Desktop API in Java SE 6

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