Weblogic BLOB Cast Exception

Question

We have an interesting situation where have to support our application on
both Weblogic 6.1 SP2 using an Oracle Type 2 driver and iPlanet using an
Oracle Type 4 driver. In our application we are using blob's, and in order
for our blob's to work with the Type 4 driver we must do a two stage process
where we insert an Oracle EMPTY_BLOB and then select the newly inserted
blob, cast it to oracle.sql.BLOB and upload it using streams.
Unfortunately, when this code runs on WLS the datasource/connection pool
substitutes some wrapper classes (or something) behind the scenes and we get
class cast exceptions as the blob is of type
weblogic.jdbc.rmi.SerialOracleBlob.
Is there any way to configure WLS connection pools/datasources so that it
doesn't use any weblogic classes and only uses oracle classes? We currently
have our 3rd Party Oracle drivers as the first entry in our classpath. We
can't switch to Oracle Type 2 on iPlanet (too buggy), or this would all be
moot and we'd simply use the more generic non-vendor specific way of
uploading blob's. And we can't cast to weblogic classes, because then that
would break on iPlanet.
Here's the code snippet that we can't change, because we have to support
Oracle Type 4 on iPlanet.
ResultSet blobs = ustmt.executeQuery();
blobs.next();
Blob blob = blobs.getBlob(1);
OutputStream blobOut = ((oracle.sql.BLOB)
blob).getBinaryOutputStream();
try {
blobOut.write(attachment.getFile());
} catch (IOException e) {
throw new ServletException(e);
} finally {
try {
blobOut.close();
} catch (IOException e) {
throw new ServletException(e);
blobs.close();
Thanks,
Gary

Answer 1

Hi Gary!
Blob oracle extensions are implemented internally in weblogic as
weblogic.jdbc.rmi.SerialOracleBlob. As we wrap objects internally for
serialization purpose, we can not use oracle objects directly. So, you have to
use SerialBlob in weblogic.
Mitesh
Gary Rudolph wrote:
We have an interesting situation where have to support our application on
both Weblogic 6.1 SP2 using an Oracle Type 2 driver and iPlanet using an
Oracle Type 4 driver. In our application we are using blob's, and in order
for our blob's to work with the Type 4 driver we must do a two stage process
where we insert an Oracle EMPTY_BLOB and then select the newly inserted
blob, cast it to oracle.sql.BLOB and upload it using streams.
Unfortunately, when this code runs on WLS the datasource/connection pool
substitutes some wrapper classes (or something) behind the scenes and we get
class cast exceptions as the blob is of type
weblogic.jdbc.rmi.SerialOracleBlob.
Is there any way to configure WLS connection pools/datasources so that it
doesn't use any weblogic classes and only uses oracle classes? We currently
have our 3rd Party Oracle drivers as the first entry in our classpath. We
can't switch to Oracle Type 2 on iPlanet (too buggy), or this would all be
moot and we'd simply use the more generic non-vendor specific way of
uploading blob's. And we can't cast to weblogic classes, because then that
would break on iPlanet.
Here's the code snippet that we can't change, because we have to support
Oracle Type 4 on iPlanet.
ResultSet blobs = ustmt.executeQuery();
blobs.next();
Blob blob = blobs.getBlob(1);
OutputStream blobOut = ((oracle.sql.BLOB)
blob).getBinaryOutputStream();
try {
blobOut.write(attachment.getFile());
} catch (IOException e) {
throw new ServletException(e);
} finally {
try {
blobOut.close();
} catch (IOException e) {
throw new ServletException(e);
blobs.close();
Thanks,
Gary