JDBC: Send BLOB field to a file

Question

Hi all,
I'm sending a JDBC record to a file but I'm wondering how I can send a BLOB (Binary large object) to a file.
Can anyone advise me how I can write such a file (eg a JPEG file) on a directory?
Thanks in advance!
Regards,
Wouter.

Answer 1

Hi,
I have found some java code that should help me write a BLOB column to a OS file:
     * Method used to write the contents (data) from an Oracle BLOB column to
     * an O/S file. This method uses one of two ways to get data from the BLOB
     * column - namely the getBytes() method. The other way to read data from an
     * Oracle BLOB column is to use Streams.
     * @throws java.io.IOException
     * @throws java.sql.SQLException
   // public void readBLOBToFileGet()
     //       throws IOException, SQLException {
        Connection      conn                    = null;
        String          outputBinaryFileName1   = null;
        File            outputBinaryFile1       = null;
        FileOutputStream    outputFileOutputStream      = null;
        String              sqlText                     = null;
        Statement           stmt                        = null;
        ResultSet           rset                        = null;
        BLOB                image                       = null;
        long                blobLength;
        long                position;
        int                 chunkSize;
        byte[]              binaryBuffer;
        int                 bytesRead                   = 0;
        int                 bytesWritten                = 0;
        int                 totbytesRead                = 0;
        int                 totbytesWritten             = 0;
        try {
            stmt = conn.createStatement();
            outputBinaryFile1       = new File(outputBinaryFileName1);
            outputFileOutputStream  = new FileOutputStream(outputBinaryFile1);
            sqlText =
                "SELECT image " +
                "FROM   test_blob " +
                "WHERE  id = 1 " +
                "FOR UPDATE";
            rset = stmt.executeQuery(sqlText);
            rset.next();
            image = ((OracleResultSet) rset).getBLOB("image");
            blobLength = image.length();
            chunkSize = image.getChunkSize();
            binaryBuffer = new byte[chunkSize];
            for (position = 1; position <= blobLength; position += chunkSize) {
                // Loop through while reading a chunk of data from the BLOB
                // column using the getBytes() method. This data will be stored
                // in a temporary buffer that will be written to disk.
                bytesRead = image.getBytes(position, chunkSize, binaryBuffer);
                // Now write the buffer to disk.
                outputFileOutputStream.write(binaryBuffer, 0, bytesRead);
                totbytesRead += bytesRead;
                totbytesWritten += bytesRead;
            outputFileOutputStream.close();
            conn.commit();
            rset.close();
            stmt.close();
            System.out.println(
                "==========================================================\n" +
                "  GET METHOD\n" +
                "==========================================================\n" +
                "Wrote BLOB column data to file " + outputBinaryFile1.getName() + ".\n" +
                totbytesRead + " bytes read.\n" +
                totbytesWritten + " bytes written.\n"
        } catch (IOException e) {
            System.out.println("Caught I/O Exception: (Write BLOB value to file - Get Method).");
            e.printStackTrace();
            throw e;
        } catch (SQLException e) {
            System.out.println("Caught SQL Exception: (Write BLOB value to file - Get Method).");
            System.out.println("SQL:\n" + sqlText);
            e.printStackTrace();
            throw e;
But how I should import the package in order to use the BLOB datatype?
Thx already for your help!
Regards,
Wouter.