public String leerBlob(ResultSet rs,String blob){
        String returndata="";
        ByteArrayOutputStream baos = new ByteArrayOutputStream(1024);
        BufferedInputStream bis;
        try {
            bis = new BufferedInputStream(rs.getBinaryStream(blob));
            byte[] bindata=new byte[1024];
            int bytesread = 0;
            try {
                if ( !rs.wasNull() ) {
                    if ( (bytesread = bis.read(bindata,0,bindata.length)) != -1 ) {
                        baos.write(bindata,0,bytesread);
                        returndata= baos.toString();
                    }
                    bis.close();
                }
            } catch (IOException e) {
                System.out.println("leerBlob -- Se produjo un error en la consulta");
                System.out.println(e.getMessage());
            }
        } catch (SQLException ex) {
            System.out.println("leerBlob -- Se produjo un error en la consulta");
            System.out.println(ex.getMessage());
        }
        return returndata;
    }