[armedbear-devel] Connection to database via JDBC and classpath

[Mark Evenson]

On 5/18/12 12:14 , Alessio Stalla wrote:
> On Fri, May 18, 2012 at 11:20 AM, Francisco Vides Fernández
>
[…]
>> I intend to use ABCL in one of my projects. I've started to connectiing to a
>> postgresq database via jdbc. I've tried something like:
>>
>> -------8<-------
>> (add-to-classpath
>>   (merge-pathnames
>> #p".m2/repository/postgresql/postgresql/8.4-702.jdbc4/postgresql-8.4-702.jdbc4.jar"
>>            (user-homedir-pathname)))
>>
>> (jstatic "forName" "java.lang.Class"  "org.postgresql.Driver")
>> -------8<-------
>>
>> But it always returns
>> -------8<-------
>> Java exception 'java.lang.ClassNotFoundException: org.postgresql.Driver'.
>>     [Condition of type JAVA-EXCEPTION]

> Or you can revert to Class.forName, but ensuring to use the overload
> that takes an explicit classloader, and feeding it the one used by
> ABCL (look in java.lisp to see how to retrieve it).
>
> On the long term, though, jclass really needs to take an extra
> argument to force initialization.

[…]

One might try using the JSS:NEW operator which has a slightly more 
aggressive method of locating Java classes with the 
[java.sql.DriverManager API][1], which is the preferred way of loading 
JDBC drivers rather than the Class.forName() method.

[1]: http://docs.oracle.com/javase/6/docs/api/java/sql/DriverManager.html

For loading Oracle drivers, the following code works for me.  I would 
expect that it would for Postgres as well with suitable modification of 
the parameters.

(require 'abcl-contrib)
(require 'abcl-asdf)
(require 'jss)

(defparameter *driver-pathname*
   "~/dist/ojdbc6.jar")
(defparameter *driver-class*
   "oracle.jdbc.OracleDriver")

(defun ensure-driver ()
   (java:add-to-classpath *driver-pathname*)
   (#"registerDriver" 'java.sql.DriverManager (new *driver-class*)))


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