And another thing... Tim Quinn's Blog

Some app clients may accept command-line arguments or use certain property settings. This post describes how you use the GlassFish Java Web Start feature to pass them to your app client.

You are probably used to just putting these settings on the appclient command line like this:

appclient -client myclient.jar -Dcolor=red -shape rectangle

It's not quite that simple when you launch the client using the Java Web Start feature in GlassFish. But it's not too bad.

Passing Arguments

You can specify arguments and properties by adding a query expression to the URL you use to launch your app client. Any query parameter with the name arg is passed exactly as-is as a command-line argument to the app client. If your client expects arguments like this:

-shape rectangle

then you will pass two arguments like this:

http://<host>:<port>/<launch-url>?arg=-shape&arg=rectangle

(See my earlier posts about the default URL path and how you can customize the path.) Note that the minus sign that introduces the “shape” keyword is included in the first query parameter value. It's your client – not any GlassFish code – that interprets the minus sign as a keyword introducer, just as with any Java application you might write that deals with command-line arguments. That's why you set “-shape” and “rectangle” up as two separate arguments in the query string.

Setting Properties

Suppose your client works with a property that you might normally specify on a Java command line using

-Dcolor=red

for example. You can specify properties via the Java Web Start feature using prop query parameters in the URL:

http://<host>:<port>/<launch-url>?prop=color=red

Notice that the GlassFish Java Web Start feature will interpret everything after the first equals sign in the “prop” expression as <property-name>=<value>. So in this example the property “color” will be set to the value “red.” The setting ?prop=equation=y=2*x would set the property “equation” to the value “y=2*x” when your client is started. The setting ?prop=xyz would set the property “xyz” to the empty string.

Arguments and Properties

You can combine arguments and properties in any order. Your client will receive the arguments in the order they appear in the query string. Here is an example that assigns the arguments and properties from the earlier examples in one URL:

http://<host>:<port>/<launch-url>?arg=-shape&arg=rectangle&prop=color=red

You probably do not want end-users to have to type such URLs into their browsers to launch the app client. Consider building a web page with a link that includes the query string. Or perhaps a dynamic page would gather some input and prepare the URL for the user accordingly.

GlassFish Java Web Start