Java/Development Class/System Browser
Access client web browser from java
<source lang="java">
/*
* This code is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This code is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this program; if not, write to the Free * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, * MA 02111-1307, USA. */
//package no.geosoft.cc.io;
import java.io.File; import java.io.FileNotFoundException; import java.io.IOException; import java.net.URL; import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method;
/**
* Browser is a class that provides one static method, openURL, which * opens the default web browser for the current user of the system to the * given URL. It may support other protocols depending on the system -- * mailto, ftp, etc. -- but that has not been rigorously tested and is not * guaranteed to work.*
* Yes, this is platform-specific code, and yes, it may rely on classes on
* certain platforms that are not part of the standard JDK. What we"re trying
* to do, though, is to take something that"s frequently desirable but
* inherently platform-specific -- opening a default browser -- and allow
* programmers (you, for example) to do so without worrying about dropping
* into native code or doing anything else similarly evil.
* <p>
* Anyway, this code is completely in Java and will run on all
* JDK 1.1-compliant systems without modification or a need for additional
* libraries. All classes that are required on certain platforms to allow
* this to run are dynamically loaded at runtime via reflection and, if not
* found, will not cause this to do anything other than returning an error
* when opening the browser.
* <p>
* There are certain system requirements for this class, as it"s running
* through Runtime.exec(), which is Java"s way of making a native system call.
* Currently, this requires that a Macintosh have a Finder which supports the
* GURL event, which is true for Mac OS 8.0 and 8.1 systems that have the
* Internet Scripting AppleScript dictionary installed in the Scripting
* Additions folder in the Extensions folder (which is installed by default
* as far as I know under Mac OS 8.0 and 8.1), and for all Mac OS 8.5 and
* later systems. On Windows, it only runs under Win32 systems (Windows 95,
* 98, and NT 4.0, as well as later versions of all). On other systems, this
* drops back from the inherently platform-sensitive concept of a default
* browser and simply attempts to launch Netscape via a shell command.
* <p>
* This code is Copyright 1999-2001 by Eric Albert (ejalbert@cs.stanford.edu)
* and may be redistributed or modified in any form without restrictions as
* long as the portion of this comment from this paragraph through the end of
* the comment is not removed. The author requests that he be notified of
* any application, applet, or other binary that makes use of this code, but
* that"s more out of curiosity than anything and is not required. This
* software includes no warranty. The author is not repsonsible for any loss
* of data or functionality or any adverse or unexpected effects of using
* this software.
* <p>
* Credits:
*
Steven Spencer, JavaWorld magazine
* (
* Added methods to the API and adjusted the linux version slightly.
*/
public class Browser {
/**
* The Java virtual machine that we are running on. Actually, in most cases
* we only care about the operating system, but some operating systems
* require us to switch on the VM. */
private static int jvm;
/** The browser for the system */
private static Object browser;
/**
* Caches whether any classes, methods, and fields that are not part of the
* JDK and need to be dynamically loaded at runtime loaded successfully.
* <p>
* Note that if this is false, openURL() will
* always return an IOException.
*/
private static boolean loadedWithoutErrors;
/** The com.apple.mrj.MRJFileUtils class */
private static Class mrjFileUtilsClass;
/** The com.apple.mrj.MRJOSType class */
private static Class mrjOSTypeClass;
/** The com.apple.MacOS.AEDesc class */
private static Class aeDescClass;
/** The <init>(int) method of com.apple.MacOS.AETarget */
private static Constructor aeTargetConstructor;
/** The <init>(int, int, int) method of com.apple.MacOS.AppleEvent */
private static Constructor appleEventConstructor;
/** The <init>(String) method of com.apple.MacOS.AEDesc */
private static Constructor aeDescConstructor;
/** The findFolder method of com.apple.mrj.MRJFileUtils */
private static Method findFolder;
/** The getFileCreator method of com.apple.mrj.MRJFileUtils */
private static Method getFileCreator;
/** The getFileType method of com.apple.mrj.MRJFileUtils */
private static Method getFileType;
/** The openURL method of com.apple.mrj.MRJFileUtils */
private static Method openURL;
/** The makeOSType method of com.apple.MacOS.OSUtils */
private static Method makeOSType;
/** The putParameter method of com.apple.MacOS.AppleEvent */
private static Method putParameter;
/** The sendNoReply method of com.apple.MacOS.AppleEvent */
private static Method sendNoReply;
/** Actually an MRJOSType pointing to the System Folder on a Macintosh */
private static Object kSystemFolderType;
/** The keyDirectObject AppleEvent parameter type */
private static Integer keyDirectObject;
/** The kAutoGenerateReturnID AppleEvent code */
private static Integer kAutoGenerateReturnID;
/** The kAnyTransactionID AppleEvent code */
private static Integer kAnyTransactionID;
/** The linkage object required for JDirect 3 on Mac OS X. */
private static Object linkage;
/** The framework to reference on Mac OS X */
private static final String JDirect_MacOSX = "/System/Library/Frameworks/Carbon.framework/Frameworks/HIToolbox.framework/HIToolbox";
/** JVM constant for MRJ 2.0 */
private static final int MRJ_2_0 = 0;
/** JVM constant for MRJ 2.1 or later */
private static final int MRJ_2_1 = 1;
/** JVM constant for Java on Mac OS X 10.0 (MRJ 3.0) */
private static final int MRJ_3_0 = 3;
/** JVM constant for MRJ 3.1 */
private static final int MRJ_3_1 = 4;
/** JVM constant for any Windows NT JVM */
private static final int WINDOWS_NT = 5;
/** JVM constant for any Windows 9x JVM */
private static final int WINDOWS_9x = 6;
/** JVM constant for any other platform */
private static final int OTHER = -1;
/**
* The file type of the Finder on a Macintosh. Hardcoding "Finder" would
* keep non-U.S. English systems from working properly.
*/
private static final String FINDER_TYPE = "FNDR";
/**
* The creator code of the Finder on a Macintosh, which is needed to send
* AppleEvents to the application.
*/
private static final String FINDER_CREATOR = "MACS";
/** The name for the AppleEvent type corresponding to a GetURL event. */
private static final String GURL_EVENT = "GURL";
/**
* The first parameter that needs to be passed into Runtime.exec() to open
* the default web browser on Windows.
*/
private static final String FIRST_WINDOWS_PARAMETER = "/c";
/** The second parameter for Runtime.exec() on Windows. */
private static final String SECOND_WINDOWS_PARAMETER = "start";
/**
* The third parameter for Runtime.exec() on Windows. This is a "title"
* parameter that the command line expects. Setting this parameter allows
* URLs containing spaces to work.
*/
private static final String THIRD_WINDOWS_PARAMETER = "\"\"";
/**
* The shell parameters for Netscape that opens a given URL in an
* already-open copy of Netscape on many command-line systems.
*/
private static final String NETSCAPE_REMOTE_PARAMETER = "-remote";
private static final String NETSCAPE_OPEN_PARAMETER_START = "openURL(";
private static final String NETSCAPE_OPEN_PARAMETER_END = ")";
/**
* The message from any exception thrown throughout the initialization
* process.
*/
private static String errorMessage;
/**
* An initialization block that determines the operating system and loads
* the necessary runtime data.
*/
static {
loadedWithoutErrors = true;
String osName = System.getProperty ("os.name");
if (osName.startsWith ("Mac OS")) {
String mrjVersion = System.getProperty("mrj.version");
String majorMRJVersion = mrjVersion.substring(0, 3);
try {
double version = Double.valueOf(majorMRJVersion).doubleValue();
if (version == 2) {
jvm = MRJ_2_0;
}
else if (version >= 2.1 && version < 3) {
// Assume that all 2.x versions of MRJ work the same.
// MRJ 2.1 actually works via Runtime.exec() and 2.2 supports that
// but has an openURL() method as well that we currently ignore.
jvm = MRJ_2_1;
}
else if (version == 3.0) {
jvm = MRJ_3_0;
}
else if (version >= 3.1) {
// Assume that all 3.1 and later versions of MRJ work the same.
jvm = MRJ_3_1;
}
else {
loadedWithoutErrors = false;
errorMessage = "Unsupported MRJ version: " + version;
}
}
catch (NumberFormatException nfe) {
loadedWithoutErrors = false;
errorMessage = "Invalid MRJ version: " + mrjVersion;
}
}
else if (osName.startsWith("Windows")) {
if (osName.indexOf("9") != -1) {
jvm = WINDOWS_9x;
}
else {
jvm = WINDOWS_NT;
}
}
else {
jvm = OTHER;
}
if (loadedWithoutErrors) { // if we haven"t hit any errors yet
loadedWithoutErrors = loadClasses();
}
}
/**
* This class should be never be instantiated; this just ensures so.
*/
private Browser() {}
/**
* Called by a static initializer to load any classes, fields, and methods
* required at runtime to locate the user"s web browser.
* @return true if all intialization succeeded
* false if any portion of the initialization failed
*/
private static boolean loadClasses() {
switch (jvm) {
case MRJ_2_0:
try {
Class aeTargetClass = Class.forName("com.apple.MacOS.AETarget");
Class osUtilsClass = Class.forName("com.apple.MacOS.OSUtils");
Class appleEventClass = Class.forName("com.apple.MacOS.AppleEvent");
Class aeClass = Class.forName("com.apple.MacOS.ae");
aeDescClass = Class.forName("com.apple.MacOS.AEDesc");
aeTargetConstructor = aeTargetClass.getDeclaredConstructor (new Class [] { int.class });
appleEventConstructor = appleEventClass.getDeclaredConstructor(new Class[] { int.class, int.class, aeTargetClass, int.class, int.class });
aeDescConstructor = aeDescClass.getDeclaredConstructor(new Class[] { String.class });
makeOSType = osUtilsClass.getDeclaredMethod("makeOSType", new Class [] { String.class });
putParameter = appleEventClass.getDeclaredMethod("putParameter", new Class[] { int.class, aeDescClass });
sendNoReply = appleEventClass.getDeclaredMethod("sendNoReply", new Class[] { });
Field keyDirectObjectField = aeClass.getDeclaredField("keyDirectObject");
keyDirectObject = (Integer) keyDirectObjectField.get(null);
Field autoGenerateReturnIDField = appleEventClass.getDeclaredField("kAutoGenerateReturnID");
kAutoGenerateReturnID = (Integer) autoGenerateReturnIDField.get(null);
Field anyTransactionIDField = appleEventClass.getDeclaredField("kAnyTransactionID");
kAnyTransactionID = (Integer) anyTransactionIDField.get(null);
}
catch (ClassNotFoundException cnfe) {
errorMessage = cnfe.getMessage();
return false;
}
catch (NoSuchMethodException nsme) {
errorMessage = nsme.getMessage();
return false;
}
catch (NoSuchFieldException nsfe) {
errorMessage = nsfe.getMessage();
return false;
}
catch (IllegalAccessException iae) {
errorMessage = iae.getMessage();
return false;
}
break;
case MRJ_2_1:
try {
mrjFileUtilsClass = Class.forName("com.apple.mrj.MRJFileUtils");
mrjOSTypeClass = Class.forName("com.apple.mrj.MRJOSType");
Field systemFolderField = mrjFileUtilsClass.getDeclaredField("kSystemFolderType");
kSystemFolderType = systemFolderField.get(null);
findFolder = mrjFileUtilsClass.getDeclaredMethod("findFolder", new Class[] { mrjOSTypeClass });
getFileCreator = mrjFileUtilsClass.getDeclaredMethod("getFileCreator", new Class[] { File.class });
getFileType = mrjFileUtilsClass.getDeclaredMethod("getFileType", new Class[] { File.class });
}
catch (ClassNotFoundException cnfe) {
errorMessage = cnfe.getMessage();
return false;
}
catch (NoSuchFieldException nsfe) {
errorMessage = nsfe.getMessage();
return false;
}
catch (NoSuchMethodException nsme) {
errorMessage = nsme.getMessage();
return false;
}
catch (SecurityException se) {
errorMessage = se.getMessage();
return false;
}
catch (IllegalAccessException iae) {
errorMessage = iae.getMessage();
return false;
}
break;
case MRJ_3_0:
try {
Class linker = Class.forName("com.apple.mrj.jdirect.Linker");
Constructor constructor = linker.getConstructor(new Class[]{ Class.class });
linkage = constructor.newInstance(new Object[] { Browser.class });
}
catch (ClassNotFoundException cnfe) {
errorMessage = cnfe.getMessage();
return false;
}
catch (NoSuchMethodException nsme) {
errorMessage = nsme.getMessage();
return false;
}
catch (InvocationTargetException ite) {
errorMessage = ite.getMessage();
return false;
}
catch (InstantiationException ie) {
errorMessage = ie.getMessage();
return false;
}
catch (IllegalAccessException iae) {
errorMessage = iae.getMessage();
return false;
}
break;
case MRJ_3_1:
try {
mrjFileUtilsClass = Class.forName("com.apple.mrj.MRJFileUtils");
openURL = mrjFileUtilsClass.getDeclaredMethod("openURL", new Class[] { String.class });
}
catch (ClassNotFoundException cnfe) {
errorMessage = cnfe.getMessage();
return false;
}
catch (NoSuchMethodException nsme) {
errorMessage = nsme.getMessage();
return false;
}
break;
default:
break;
}
return true;
}
/**
* Attempts to locate the default web browser on the local system.
* Caches results so it only locates the browser once for each use of this
* class per JVM instance.
*
* @return The browser for the system. Note that this may not be what you
* would consider to be a standard web browser; instead, it"s the
* application that gets called to open the default web browser. In some
* cases, this will be a non-String object that provides the means of
* calling the default browser.
*/
private static Object locateBrowser()
{
if (browser != null) {
return browser;
}
switch (jvm) {
case MRJ_2_0:
try {
Integer finderCreatorCode = (Integer) makeOSType.invoke(null, new Object[] { FINDER_CREATOR });
Object aeTarget = aeTargetConstructor.newInstance(new Object[] { finderCreatorCode });
Integer gurlType = (Integer) makeOSType.invoke(null, new Object[] { GURL_EVENT });
Object appleEvent = appleEventConstructor.newInstance(new Object[] { gurlType, gurlType, aeTarget, kAutoGenerateReturnID, kAnyTransactionID });
// Don"t set browser = appleEvent because then the next time we call
// locateBrowser(), we"ll get the same AppleEvent, to which we"ll
// already have added the relevant parameter. Instead, regenerate
// the AppleEvent every time. There"s probably a way to do this
// better; if any has any ideas, please let me know.
return appleEvent;
}
catch (IllegalAccessException iae) {
browser = null;
errorMessage = iae.getMessage();
return browser;
}
catch (InstantiationException ie) {
browser = null;
errorMessage = ie.getMessage();
return browser;
}
catch (InvocationTargetException ite) {
browser = null;
errorMessage = ite.getMessage();
return browser;
}
case MRJ_2_1:
File systemFolder;
try {
systemFolder = (File) findFolder.
invoke (null, new Object[] { kSystemFolderType });
}
catch (IllegalArgumentException iare) {
browser = null;
errorMessage = iare.getMessage();
return browser;
}
catch (IllegalAccessException iae) {
browser = null;
errorMessage = iae.getMessage();
return browser;
}
catch (InvocationTargetException ite) {
browser = null;
errorMessage = ite.getTargetException().getClass() + ": " +
ite.getTargetException().getMessage();
return browser;
}
// Avoid a FilenameFilter because that can"t be stopped mid-list
String[] systemFolderFiles = systemFolder.list();
for (int i = 0; i < systemFolderFiles.length; i++) {
try {
File file = new File(systemFolder, systemFolderFiles[i]);
if (!file.isFile()) {
continue;
}
// We"re looking for a file with a creator code of "MACS" and
// a type of "FNDR". Only requiring the type results in non-Finder
// applications being picked up on certain Mac OS 9 systems,
// especially German ones, and sending a GURL event to those
// applications results in a logout under Multiple Users.
Object fileType = getFileType.invoke(null, new Object[] { file });
if (FINDER_TYPE.equals (fileType.toString())) {
Object fileCreator = getFileCreator.
invoke(null, new Object[] { file });
if (FINDER_CREATOR.equals(fileCreator.toString())) {
// Actually the Finder, but that"s OK
browser = file.toString();
return browser;
}
}
}
catch (IllegalArgumentException iare) {
browser = browser;
errorMessage = iare.getMessage();
return null;
}
catch (IllegalAccessException iae) {
browser = null;
errorMessage = iae.getMessage();
return browser;
}
catch (InvocationTargetException ite) {
browser = null;
errorMessage = ite.getTargetException().getClass() + ": " +
ite.getTargetException().getMessage();
return browser;
}
}
browser = null;
break;
case MRJ_3_0:
case MRJ_3_1:
browser = ""; // Return something non-null
break;
case WINDOWS_NT:
browser = "cmd.exe";
break;
case WINDOWS_9x:
browser = "command.ru";
break;
case OTHER:
default:
browser = "netscape";
break;
}
return browser;
}
/**
* Open the specified file in the client web browser.
*
* @param file File to open
* @throws IOException If there is brwoser problem.
*
*/
public static void openUrl (File file)
throws IOException
{
openUrl ("file://" + file.getPath());
}
/**
* Open the specified URL in the client web browser.
*
* @param url URL to open.
* @throws IOException If there is brwoser problem.
*/
public static void openUrl (URL url)
throws IOException
{
openUrl (url.toString());
}
/**
* Open the specified URL in the client web browser.
*
* @param url URL to open.
* @throws IOException If there is brwoser problem.
*/
public static void openUrl (String url)
throws IOException
{
if (!loadedWithoutErrors) {
throw new IOException("Exception in finding browser: " + errorMessage);
}
Object browser = locateBrowser();
if (browser == null) {
throw new IOException("Unable to locate browser: " + errorMessage);
}
switch (jvm) {
case MRJ_2_0:
Object aeDesc = null;
try {
aeDesc = aeDescConstructor.newInstance(new Object[] { url });
putParameter.invoke(browser, new Object[] { keyDirectObject,
aeDesc });
sendNoReply.invoke(browser, new Object[] { });
}
catch (InvocationTargetException ite) {
throw new IOException("InvocationTargetException while creating AEDesc: " + ite.getMessage());
}
catch (IllegalAccessException iae) {
throw new IOException("IllegalAccessException while building AppleEvent: " + iae.getMessage());
}
catch (InstantiationException ie) {
throw new IOException("InstantiationException while creating AEDesc: " + ie.getMessage());
}
finally {
aeDesc = null; // Encourage it to get disposed if it was created
browser = null; // Ditto
}
break;
case MRJ_2_1:
Runtime.getRuntime().exec(new String[] { (String) browser, url } );
break;
case MRJ_3_0:
int[] instance = new int[1];
int result = ICStart(instance, 0);
if (result == 0) {
int[] selectionStart = new int[] { 0 };
byte[] urlBytes = url.getBytes();
int[] selectionEnd = new int[] { urlBytes.length };
result = ICLaunchURL(instance[0], new byte[] { 0 }, urlBytes,
urlBytes.length, selectionStart,
selectionEnd);
if (result == 0) {
// Ignore the return value; the URL was launched successfully
// regardless of what happens here.
ICStop(instance);
}
else {
throw new IOException("Unable to launch URL: " + result);
}
}
else {
throw new IOException("Unable to create an Internet Config instance: " + result);
}
break;
case MRJ_3_1:
try {
openURL.invoke(null, new Object[] { url });
}
catch (InvocationTargetException ite) {
throw new IOException("InvocationTargetException while calling openURL: " + ite.getMessage());
}
catch (IllegalAccessException iae) {
throw new IOException("IllegalAccessException while calling openURL: " + iae.getMessage());
}
break;
case WINDOWS_NT:
case WINDOWS_9x:
// Add quotes around the URL to allow ampersands and other special
// characters to work.
Process process = Runtime.getRuntime().
exec(new String[] {(String) browser,
FIRST_WINDOWS_PARAMETER,
SECOND_WINDOWS_PARAMETER,
THIRD_WINDOWS_PARAMETER,
""" + url + """ });
// This avoids a memory leak on some versions of Java on Windows.
// That"s hinted at in <http://developer.java.sun.ru/developer/qow/
// archive/68/>.
try {
process.waitFor();
process.exitValue();
}
catch (InterruptedException ie) {
throw new IOException("InterruptedException while launching browser: " + ie.getMessage());
}
break;
case OTHER:
// Assume that we"re on Unix and that Netscape is installed
// First, attempt to open the URL in a currently running session of
// Netscape
String command = browser.toString() + " -raise " +
NETSCAPE_REMOTE_PARAMETER + " " +
NETSCAPE_OPEN_PARAMETER_START +
url + NETSCAPE_OPEN_PARAMETER_END;
process = Runtime.getRuntime().exec (command);
try {
int exitCode = process.waitFor();
if (exitCode != 0) { // if Netscape was not open
Runtime.getRuntime().exec(new String[] { (String) browser, url });
}
}
catch (InterruptedException exception) {
exception.printStackTrace();
throw new IOException("InterruptedException while launching browser: " + exception.getMessage());
}
break;
default:
// This should never occur, but if it does, we"ll try the simplest
// thing possible
Runtime.getRuntime().exec (new String[] {(String) browser, url});
break;
}
}
/**
* Methods required for Mac OS X. The presence of native methods does not
* cause any problems on other platforms.
*/
private native static int ICStart (int[] instance, int signature);
private native static int ICStop (int[] instance);
private native static int ICLaunchURL (int instance, byte[] hint, byte[]
data, int len,
int[] selectionStart,
int[] selectionEnd);
}
</source>
