EJB-BLOB problem.

[rohit]

Hi,
I am trying to insert a blob object in the oracle 8i database using ejb session bean .i am using the BLOB class of oracle.sql package however it throws the following exception
java.lang.ClassCastException: org.jboss.pool.jdbc.ResultSetInPool.

when the method is executed.

i am using the following code.

strQuery="SELECT APPL_REF_MATERIAL_BLOB FROM PTS_APPL_REF_MATERIAL WHERE APPL_REF_MATERIAL_ID="+strPk;
//strPk is the primary key.
stmt=con.createStatement();
rs=stmt.executeQuery(strQuery);
while(rs.next())
{

BLOB blob=((OracleResultSet)rs).getBLOB(1);
//error is thrown on above line
FileInputStream instream=new FileInputStream(appRef.getRefMaterial());//returns a file object
OutputStream outStream=blob.getBinaryOutputStream();
int size=blob.getBufferSize();
byte buffer[]=new byte[size];
int length=-1;
while((length=instream.read(buffer))!=-1)
{
outStream.write(buffer,0,length);
}
instream.close();
outStream.close();

}

[amccullo]

I am fairly new at this so I may be way off but it is probably better to use the java.sql.Blob class instead of the Oracle specific BLOB object.

Blob blob = rs.getBlob(1);

Your class cast exception comes from the fact that the ResultSet you get back does not inherit from the Oracle version. I don't think you can use JBoss connection pooling and still use the non-standard Oracle functionality. If you need the Oracle functionality you will have to use the DriverManager.getConnection(url). Or at least that is what I have found.

[rohit]

Hello ,
I am intending to save a blob to the table and not retrieve it.The original code saves a blob to the database.
Blob interface which is provided by java.sql.* package doesnt have any method which returns the outputstream object.
That is the reason why I have used BLOB of oracle.sql package.

[davidjencks]

BLOB blob=((OracleResultSet)(rs.getUnderlyingResultSet())).getBLOB(1);

[rohit]

Thanks.
I tried this code but it throws the following compilation error.
cannot resolve symbol
symbol : method getUnderlyingResultSet ()
location: interface java.sql.ResultSet
BLOB blob=((OracleResultSet)(rs.getUnderlyingResultSet())).getBLOB(1);

Compiler tries to find the method getUnderlyingResultSet() in java.sql.ResultSet interface which it doesnt find hence the error.

[amccullo]

You must cast the 'rs' object to "org.jboss.pool.jdbc.ResultSetInPool" before you can call the getUnderlyingResultSet method.

BLOB blob =
((OracleResultSet)(((org.jboss.pool.jdbc.ResultSetInPool)rs).getUnderlyingResultSet())).getBLOB(1);

Let me know if that works as I have not tried it.

[davidjencks]

Yes, use your imagination;-). You may also need to cast to the Oracle blob type.