Zipping multiple BLOBs

cdefelice <>
Thu, 18 Feb 2010 14:37:30 -0800 (PST)

First of all, I have virtually no experience with Java but I've been
tasked with putting this thing together and I've finally hit a dead
end. Basically, what I am creating is a PL/SQL (Oracle 10g) web form
so that clients may download specific files stored as BLOBs from the
database. This is fine and dandy if they want to download one file at
a time. What I need to do is come up with a way to pull multiple BLOB
files, zip them up in one big BLOB, and serve it as a download. Since
this cannot be done in PL/SQL alone, I turned to Java.

So far I have not been able to find one successful example of how to
do this. What I have so far produces a zip file with only the first of
the selected BLOBs inside of it. I am basically just looping through
the list of selected BLOBs while passing each selected BLOB to the
Java procedure as well as the zip BLOB but it doesn't seem to be
appending anything to the zipped BLOB after the first iteration. Here
is the code:

        public static void zipBlob(oracle.sql.BLOB srcBlob, oracle.sql.BLOB
dstBlob[],java.lang.String name)
                Connection conn =

                OutputStream outBuffer = dstBlob[0].setBinaryStream(0);
                InputStream inBuffer = srcBlob.getBinaryStream();
                ZipOutputStream zip = new ZipOutputStream(outBuffer);
                byte[] tmpBuffer = new byte[1024];
                ZipEntry entry = new ZipEntry(name);
                int n;

                while ((n = >= 0)
                    zip.write(tmpBuffer, 0, n);

            catch (SQLException e)
            catch (IOException e)

I appreciate any examples or pointers as to why this is not working.

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