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Ben Nadel at FirstMark Tech Summit (New York, NY) with: Atticus White
Ben Nadel at FirstMark Tech Summit (New York, NY) with: Atticus White ( @atticoos )

Listing All Classes In A Jar File Using ColdFusion

Published in Comments (5)

You'll probably never need to do this, but today, I needed to find out what Java classes were available in a given JAR file using ColdFusion. The reason - I was doing some work on my POI Utility ColdFusion custom tags and I needed to see if the version of the POI JAR that ships with ColdFusion supports certain classes. Turns out, this is a fairly straightforward task. I wrapped the functionality up in a ColdFusion user defined function that takes the expanded path to the target JAR file:

	hint="I return an array of classes in the given JAR file (expanded path).">

	<!--- Define arguments. --->
		hint="I am the expanded path of the JAR file."

	<!--- Define the local scope. --->
	<cfset var LOCAL = {} />

	<!--- Create a default array of classes. --->
	<cfset LOCAL.Classes = [] />

		Create a JAR input stream to read in the line items
		from our target JAR file.
	<cfset LOCAL.JarFile = CreateObject(



		Now that we have our JAR file input stream, let's loop
		over all the entries looking for CLASS files.
	<cfloop condition="true">

			Get the next entry. This might return NULL if the
			JAR file has no more classes.
		<cfset LOCAL.JarEntry = LOCAL.JarFile.GetNextJarEntry() />

			Check to see if the entry variable exists. If it
			does not, then it means the JAR file return NULL
			and we are done finding classes.
		<cfif StructKeyExists( LOCAL, "JarEntry" )>

				Check to make sure that this entry is not a
				directory, but is, in fact a class.
			<cfif REFindNoCase( "\.class$", LOCAL.JarEntry.GetName() )>

					Add this class to the array. Since the JAR
					file really has a directory structure, let's
					replace the path separators with dots.
				<cfset LOCAL.ClassName = REReplace(
					) />

				<!--- Strip off the ".class" path item. --->
				<cfset LOCAL.ClassName = REReplaceNoCase(
					) />

				<!--- Add the formatted class name. --->
				<cfset ArrayAppend(
					) />



			<cfbreak />



	<!--- Return the array of classes. --->
	<cfreturn LOCAL.Classes />

To call it, you just do this (I had a copy of the installed POI JAR file in the same directory as my test file):

<!--- Get file path to POI installed JAR file. --->
<cfset strJarFilePath = ExpandPath(
	) />

<!--- Output the classes. --->
	var="#GetJarClasses( strJarFilePath )#"
	label="POI 2.5.1 Final Classes"

Running this, we get an array with the following values (abbreviated):

..... several hundred classes .....

Anyway, just thought I would post that in case anyone ever needs this kind of functionality.

Want to use code from this post? Check out the license.

Reader Comments


I never really play around with JAR files much, so this comment could be totally off base, but, could you have not just used the cfzip tag? It accepts a JAR file and you could use the list action and just dumped that out, right? or am i missing the point? It's Friday so my brain has shut of ffor the weekend :-)

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Ben Nadel