Ben Nadel
On User Experience (UX) Design, JavaScript, ColdFusion, Node.js, Life, and Love.
I am the chief technical officer at InVision App, Inc - a prototyping and collaboration platform for designers, built by designers. I also rock out in JavaScript and ColdFusion 24x7.
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Ben Nadel at cf.Objective() 2011 (Minneapolis, MN) with:

Listing All Classes In A Jar File Using ColdFusion

By Ben Nadel on
Tags: ColdFusion

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:

  • <cffunction
  • name="GetJarClasses"
  • access="public"
  • returntype="array"
  • output="false"
  • hint="I return an array of classes in the given JAR file (expanded path).">
  •  
  • <!--- Define arguments. --->
  • <cfargument
  • name="JarFilePath"
  • type="string"
  • required="true"
  • 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(
  • "java",
  • "java.util.jar.JarInputStream"
  • ).Init(
  •  
  • CreateObject(
  • "java",
  • "java.io.FileInputStream"
  • ).Init(
  •  
  • JavaCast(
  • "string",
  • ARGUMENTS.JarFilePath
  • )
  • )
  • )
  • />
  •  
  •  
  • <!---
  • 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$", LOCAL.JarEntry.GetName() )>
  •  
  • <!---
  • Add this class to the array. Since the JAR
  • file really has a directory structure, let's
  • replace the path separators with dots.
  • --->
  • <cfset LOCAL.ClassName = REReplace(
  • LOCAL.JarEntry.GetName(),
  • "[\\/]",
  • ".",
  • "all"
  • ) />
  •  
  • <!--- Strip off the ".class" path item. --->
  • <cfset LOCAL.ClassName = REReplaceNoCase(
  • LOCAL.ClassName,
  • "\.class$",
  • "",
  • "one"
  • ) />
  •  
  • <!--- Add the formatted class name. --->
  • <cfset ArrayAppend(
  • LOCAL.Classes,
  • LOCAL.ClassName
  • ) />
  •  
  • </cfif>
  •  
  • <cfelse>
  •  
  • <cfbreak />
  •  
  • </cfif>
  •  
  • </cfloop>
  •  
  •  
  • <!--- Return the array of classes. --->
  • <cfreturn LOCAL.Classes />
  • </cffunction>

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(
  • "./poi-2.5.1-final-20040804.jar"
  • ) />
  •  
  • <!--- Output the classes. --->
  • <cfdump
  • var="#GetJarClasses( strJarFilePath )#"
  • label="POI 2.5.1 Final Classes"
  • />

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

org.apache.poi.ddf.DefaultEscherRecordFactory
org.apache.poi.ddf.EscherArrayProperty
org.apache.poi.ddf.EscherBSERecord
org.apache.poi.ddf.EscherBlipRecord
..... several hundred classes .....
org.apache.poi.util.ShortList
org.apache.poi.util.StringUtil
org.apache.poi.util.SystemOutLogger

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




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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