Deploy JavaFX application to JSP

Question

A lot people saying it's possible just by using the snippet below,
<script src="http://dl.javafx.com/dtfx.js"></script>
<script>
    javafx(
              archive: "Foo.jar",
              draggable: true,
              width: 200,
              height: 200,
              code: "foo.Main",
              name: "Foo"
</script> Could ANYONE tell me what's the function of code in the Java script? I think it has been included into the archive already.
One another question is, what are the functions of the JNLP file and how should I modify them to facilitate the deployment?

Answer 1

Hi Isaac,
Now those are questions I've been asking for the past few months! And by coincidence I think I've just gotten my answers today, mostly by trial and error. Bear in mind that I'm not a deployment engineer, so I stand to be corrected, but I've tested everything I'm going to say and can verify it works, at least on Windows and Mac.
I'm drawing some of my information from the following Java article but will be speaking specifically about JavaFX.
http://java.sun.com/developer/technicalArticles/javase/newapplets/
That article includes a discussion about making your applet compatible with pre-6u10 and 6u10+ runtimes. On Windows, JavaFX runtimes rely on 6u10+ Java runtimes, which use the xxx_browser.jnlp file for applet startup. However, Apple Java ignores the JNLP file for applets, which means that all of its applet startup information comes from the applet script in the HTML/JSP file, so in this regard it is behaving like a pre-6u10 Java runtime. I believe that Solaris and Linux follow the Windows model, but I haven't extended my testing that far.
So here are some general statements that I know work for Windows and Mac.
1. You can strip all the attributes out of the <jnlp> tag in your xxx_browser.jnlp file. This saves a lot of grief in changing the codebase attribute every time you move your applet. The catch is that if you remove one attribute from the <jnlp> tag, you have to remove 'em all (href and spec) to get the applet to work. And that rule is for Windows, since Mac ignores the applet JNLP.
2. Your JNLP file is found as long as it's in the same directory as your JAR file. You specify the location of your JAR file in the archive parameter of the applet script in your HTML/JSP page. That's why you don't need to call the JNLP from your applet script.
3. You can optionally specify the location of the JNLP file in your applet script by using a jnlp_href parameter, something like this:
jnlp_href: "dist/TestApp_browser.jnlp",
That specifically tells the runtime where to look for the JNLP file--in this case, in the dist/ child of the directory containing the HTML/JSP page. But note that other things happen when you use the jnlp_href attribute:
- If you do have a codebase attribute specified in your JNLP file, the jnlp_href parameter overrides it.
- When the jnlp_href parameter is specified, the applet's main class name is taken from the <param> tag nested under the <applet-desc> tag in the JNLP file, and the code parameter in the applet script is ignored. I tried deleting the code parameter in the script entirely, and the applet worked fine on Windows. However, remember that Mac doesn't use the JNLP file, so it's lost wtihout the code parameter. If you include both the jnlp_href and code parameters, both Windows and Mac are happy.
- When the jnlp_href parameter is specified, you can also delete the archive parameter in the script, and it runs on Windows. The location of the JAR file is taken from the <jar> tag, nested under the <resources> tag in the JNLP. However, the applet chokes on Mac without the archive parameter in the applet script. Again, include both the jnlp_href and archive tag to make sure your applet runs in both environments.
So why would you want to bother with the jnlp_href parameter? It's optional when the JNLP and JAR files are located in the same directory, but it's necessary if your JNLP file is in a different directory from your JAR file.
Here's an example. Suppose the xxx_browser.jnlp is in the same directory as your HTML/JSP page, and the JAR file is in a child directory called dist. Then your applet script will look like this:
<script>
javafx(
archive: "dist/TestApp.jar",
     jnlp_href: "TestApp_browser.jnlp",
width: 200,
height: 200,
code: "testapp.Main",
name: "TestApp"
</script>
and the <jar> tag in the JNLP will look like this:
<jar href="dist/TestApp.jar" main="true"/>
The <jnlp> tag in the JNLP file can either contain all the attributes that it was generated with or it can contain just the tag with no attributes:
<jnlp>
How does this work? On Windows, the runtime finds the JNLP file from the jnlp_href parameter and ignores the archive and code parameters. The location of the JAR file is determined from the <jar> tag in the JNLP. On Mac, all that is required is the location of the JAR file and the main class, which are specified in the archive and code parameters.
Unless you have a strong reason for separating the JNLP and JAR files, keep them together. Then you only need to specify the location of the JAR file in the archive tag, relative to the directory containing the HTML/JSP page. You don't have to worry about the codebase attribute and <jar> tag in the JNLP file, and you don't have to specify the jnlp_href parameter in the applet script.
Nancy