在没有结果集的情况下使用JDBC Spring读取blob

我有一个Oracle存储过程,它在输出参数中返回一个blob:

PROCEDURE GET_IMAGE_DATA(i_image_type IN NUMBER, o_image_data OUT BLOB) IS
BEGIN
        SELECT IMAGE_DATA 
         INTO o_image_data 
         FROM IMAGES 
        WHERE IMAGE_TYPE = i_image_type;

END GET_IMAGE_DATA;

我想使用JDBCSpring来读取这些数据。但是,DefaultLobHandler(我认为是OracleLobHandler)getBlobAsBytes()需要一个结果集。

private static class QueryForBinaryCryptKey extends StoredProcedure {

        private static final String SQL = "IMAGE_PKG.GET_IMAGE_DATA";
        private DefaultLobHandler lobHandler;

        QueryForImageData(DataSource dataSource) {
            super(dataSource, SQL);
            setFunction(false);
            lobHandler = new DefaultLobHandler();

            declareParameter(new SqlParameter(KEY_TYPE, OracleTypes.NUMBER));
            declareParameter(new SqlOutParameter(KEY_BLOB, OracleTypes.BLOB));

        }

        public Map getImage(int keyType) {
            Map outParams = super.execute(inParams(keyType));
                    //how can I get the contents of the blob right here since
                    //getBlobAsBytes requires a resultSet???
            return outParams;
        }

        private Map inParams(int keyType) {
            Map params = new HashMap();
            params.put(KEY_TYPE, new Integer(keyType));
            return params;
        }   
    }   

当我只有out参数而不是resultset时,如何获取blob数据?