Jython: cannot import Java packages

[Jindra]

Hello,
I developed some useful Jython script in Eclipse, using ojdbc6.jar as driver library (attached to the project as "external library"). When debugging in Eclipse, everything goes fine. Also standalone run on the development PC runs OK.

Then I copied the complete Jython 2.5.2 installation to another machine (with Java JRE 1.6.30), copied my script and the ojdbc6.jar library in the same directory as the script.

I call it with

<pathtojava>\ja va.exe -cp ojdbc6.jar -jar ..\jython2.5.2\ jython.jar myscript.py (which works on the original PC)

Now, it throws exception in this code:

from oracle.jdbc import OracleDriver
...
class SqlTester:
...
def connect( self ):
self.driver = OracleDriver()
self.connection = DriverManager.g etConnection( "jdbc:oracle:th in:@%s:%s:%s" % ( self.host, self.port, self.sid ), self.user, self.psw )
...

The exception is:

Traceback (most recent call last):
File "myscript.p y", line 119, in <module>
tester.run_all_ tests()
File "myscript.p y", line 79, in run_all_tests
self.connect()
File "myscript.p y", line 60, in connect
self.connection = DriverManager.g etConnection( "jdbc:oracle:th in:@%s:%s:%s" % ( self.host, self.port, self.sid )
at java.sql.Driver Manager.getConn ection(Unknown Source)
at java.sql.Driver Manager.getConn ection(Unknown Source)
at sun.reflect.Nat iveMethodAccess orImpl.invoke0( Native Method)
at sun.reflect.Nat iveMethodAccess orImpl.invoke(U nknown Source)
at sun.reflect.Del egatingMethodAc cessorImpl.invo ke(Unknown Source)
at java.lang.refle ct.Method.invok e(Unknown Source)
java.sql.SQLExc eption: java.sql.SQLExc eption: No suitable driver found for jdbc:oracle:thi n:@xxxxxx:1521: DWH

What am I doing wrong?

[sourabh mittal]

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[Jindra]

Hello,
finally resolved. It is not an import problem (driver imports OK, when instantiated, call to main() prints driver info).

The real problem is non-functional java.sql.Driver Manager in Jython

java.sql.Driver Manager.getConn ection() will always report "no suitable driver found" or similar, depending if it is Java 5 or Java 6.

The solution is very simple: since I have the OracleDriver class already imported, I just use it:

drv = OracleDriver()
connection = drv.connect( myJdbcUrl, java.util.Prope rties() )

In Python you can easily select and instantiate your java.sql.Driver for any database connection dynamically. So you don't need java.sql.Driver Manager, which was actually invented in Java to allow for dynamic driver selection...

I am only puzzled by one thing. This DriverManager problem seems to be the most frequent problem in Jython when using JDBC. Yet, I have not seen a single answer (on Google) to describe the correct way how to use JDBC; on the contrary, jython tutorials I saw all copy the Java stuff using DriverManager. Have nobody ever made any test to see whether what they teach is true?

[satishmoningi]

Hi Jindra,
I am also facing same issue with following jython script. Could you please verify where I went wrong.

from java.lang import Class
import sys
from java.util import Properties
sys.path.append('/opt/IBM/WASLogs/shared-libs/ojdbc6.jar')
from oracle.jdbc import OracleDriver
 
 
driver = OracleDriver()
myJdbcUrl = "jdbc:oracle:thin:@localhost:2347:PRBPMDB1"
info = Properties()
info.put ("user", "user");
info.put ("password","user1");
conn = driver.connect(myJdbcUrl,info)
stmt = conn.createStatement()
rs = stmt.executeQuery("select * from wom_message_status where id=1067")
 
while rs.next():
        print "%s" % rs.getString(3)
 
rs.close()
stmt.close()
conn.close()
 
 

Thanks,
Satish Moningi
[phone]