problems with getting blob from database

I`m writing from file to blob. Than I need to get blob content again
and write it to file. When I open this file, I see the wrong symbols.
Can anybody help me?
Here is my code:

////////////////////////////
to update file content
///////////////////////////

private void updateFileContent(File serverFile, java.io.File
clientContentFile) throws MainException
    {
        PreparedStatement preparedStatement = null;
        try
        {

            connection = connect();
           String query = "update panta_file_substance\n" +
                                "set content = ?\n" +
                                "where\n" +
                                " file_id = ?"
            preparedStatement = getPreparedStatement
                            (query, connection);

            int fileLenght = (int) clientContentFile.length();
            InputStream is = new FileInputStream(clientContentFile);
            preparedStatement.setBinaryStream(1, is, fileLenght);
            preparedStatement.setLong( 2,
serverFile.getId().longValue() );
            int result = preparedStatement.executeUpdate();
            is.close();
        }
        catch (SQLException e)
        { throw new MainException(e.getMessage(), e); }

        catch (FileNotFoundException e)
        { throw new MainException(e.getMessage(), e); }

        catch (IOException e)
        { throw new MainException(e.getMessage(), e); }

        finally
        {
            disconnect(null, preparedStatement, null);
        }
    }

//////////////////////////////////////////////////////////////////////////
to get file
/////////////////////////////////////////////////////////////////////////

    public static void getFile(Connection connection) throws
SQLException
    {
        String query = "select \n" +
                               " panta_file_substance.content \n" +
                               "from \n" +
                               " panta_file_substance\n" +
                               "where \n" +
                               " file_id=?";
        PreparedStatement preparedStatement = connection.
prepareStatement(ServerSQLProjectDAO.getFileContent());
        preparedStatement.setLong(1, 7801295236381635588l);
        ResultSet resultSet = preparedStatement.executeQuery();
        Blob content = null;
        if (resultSet.next())
        {
            content = (Blob) resultSet.getBlob("CONTENT");
        }
        java.io.File contentffFile = new java.io.File("C:\\Temp\\new");
        try
        {
            OutputStream os = new FileOutputStream(contentffFile);
            int bufferSize = 2048;
            byte[] array = new byte[bufferSize];
            BufferedOutputStream bos = new BufferedOutputStream(os,
bufferSize);

            InputStream is = content.getBinaryStream();
            BufferedInputStream bis = new BufferedInputStream(is);

            int nBytes;

            while ((nBytes = bis.read(array)) != -1)
                bos.write(array, 0, nBytes);

            bos.close();
            bis.close();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }

    }