How to register a JDBC driver using jruby-complete.jar?

Question

I'm trying to write a script that is executed with the jruby-complete.jar like so:

java -cp derby.jar; -Djdbc.drivers=org.apache.derby.jdbc.EmbeddedDriver -jar jruby-complete.jar -S my_script.rb

I'm using JVM 1.6.0_11 and JRuby 1.4.

In my jruby script I attempt to connect to the database like this.

connection = Java::com.sql.DriverManager.getConnection("jdbc:derby:path_to_my_DB")

This throws a java.sql.SQLException: "No suitable driver found" exception.

I've tried manually loading the driver into the class loader using Class.forName which gives me the same error.

It looks like to me that the class loader being used by the DriverManager is not the same as the current thread's. I've tried setting the current thread's class loader using:

JThread = java.lang.Thread 
...
class_loader = JavaLang::URLClassLoader.new(  
  [JavaLang::URL.new("jar:file:/derby.jar!/")].to_java(
    JavaLang::URL),JRuby.runtime.jruby_class_loader)      

JThread.currentThread().setContextClassLoader(class_loader )

But this doesn't help.

Any ideas?

Answer 1

First, make sure your driver jar is not corrupted (this made me waste a couple of days one time).

Second, read this about JRuby/Java classloade: JRuby Wiki

Third (because I haven't played with "jruby-complete") try this simple script and then see if you can adapt as you need.

require 'java'
require 'C:\ruby\db-derby-10.5.3.0-bin\lib\derby.jar'  # adjust for your machine
include_class "java.sql.DriverManager"
derby = org.apache.derby.jdbc.EmbeddedDriver.new
connection = DriverManager.getConnection("jdbc:derby:derbyDB;create=true")

Answer 2

OK I downloaded jruby-complete.jar and had a go....

This seems to work for me:

java -classpath c:\ruby\db-derby-10.5.3.0-bin\lib\derby.jar;jruby-complete-1.4.0.jar org.jruby.Main -S derby.rb

When using the -jar switch, the -classpath option is ignored (maybe the CLASSPATH shell var is too). But on the above line, we put both required jars on the class path and pass the class name to execute (i.e. org.jruby.Main). The script being passed in is as per my other answer.

Another option (which I have not tried) would be to alter the jruby-complete.jar manifest file to specify as classpath, as described here: Adding Classes to the JAR File's Classpath