Why I cannot cast oracle BLOB from native java Blob

Question

I am reading file from ResultSet and it's required to save file into Oracle Database.

...
ResultSet rs = ...
java.sql.Blob myfile = rs.getBlob("field")
java.io.OutputStream os = ((oracle.sql.BLOB) myfile).getBinaryOutputStream();

I get get this error message

java.lang.ClassCastException

Any one have solution to this? Thanks!

Answer 1

I have found the solution. I'd like to share with those who has this problem.

The code to get outputstream from oracle blob is:

java.io.OutputStream os = ((oracle.sql.BLOB) myBlob).setBinaryStream(1L);

setBinaryStream() is actually returning java.io.OutputStream object

Answer 2

java.sql.Blob is an interface. Presumably the implementation returned in your ResultSet is a different implementation to oracle.sql.BLOB?

What does myfile.getClass() return?