How do I auto load a database jar in Groovy without using the -cp switch?

Question

I want to simplify my execution of a Groovy script that makes calls to an Oracle database. How do I add the ojdbc jar to the default classpath so that I can run:

groovy RunScript.groovy

instead of:

groovy -cp ojdbc5.jar RunScript.groovy

Answer 1

Summarized from Groovy Recipes, by Scott Davis, Automatically Including JARs in the ./groovy/lib Directory:

1. Create .groovy/lib in your login directory

2. Uncomment the following line in ${GROOVY_HOME}/conf/groovy-starter.conf

   load !{user.home}/.groovy/lib/*.jar

3. Copy the jars you want included to .groovy/lib

It appears that for Groovy 1.5 or later you get this by default (no need to edit the conf), just drop the jars in the /lib dir.

Answer 2

There are a few ways to do it. You can add the jar to your system's CLASSPATH variable. You can create a directory called .groovy/lib in your home directory and put the jar in there. It will be automatically added to your classpath at runtime. Or, you can do it in code:

this.class.classLoader.rootLoader.addURL(new URL("file:///path to file"))

Answer 3

groovy is just a wrapper script for the Groovy JAR that sets up the Java classpath. You could modify that script to add the path to your own JAR, as well, I suppose.

Answer 4

You could add the following shebang to the first line of your Groovy script:

#!/usr/bin/env groovy -cp ojdbc5.jar

Then, mark the script executable:

chmod u+x RunScript.groovy

Now, running the script by itself will set the classpath automatically.

./RunScript.groovy