java大量数据加载时resultSetType参数的设置 TYPE_FORWARD_ONLY

    /**
     * Load each the elements using a SQL statement specifying a list of fields to be retrieved and dealt by action.
     * @param sql the SQL statement for retrieving
     * @param argList the arguments to use fill given prepared statement,may be null
     * @param fieldList table of the field's associated constants
     * @param startRow the start row to be used (first row = 1, last row = -1)//起始行号
     * @param numRows the number of rows to be retrieved (all rows = a negative number)//行数
     * @param action Action object for do something(not null)
     * @return the count dealt by action
     * @throws DAOException
     */
    public int loadBySqlForAction(String sql, Object[] argList, int[] fieldList,int startRow, int numRows,Action action) throws DAOException{
        PreparedStatement ps = null;
        Connection connection = null;
        try {
            //获取数据库连接
            connection = this.getConnection();
            //创建PreparedStatement 
            ps = connection.prepareStatement(sql,
                    1==startRow?ResultSet.TYPE_SCROLL_INSENSITIVE:ResultSet.TYPE_SCROLL_SENSITIVE,
                    ResultSet.CONCUR_READ_ONLY);
            //填充PrepareStatement中的?占位符
            fillPrepareStatement(ps, argList);
            //执行PreparedStatement 
            return this.loadByPreparedStatement(ps, fieldList, startRow, numRows, action);
        } catch (DAOException e) {
            throw e;
        }catch (SQLException e) {
            throw new DataAccessException(e);
        } finally {
            this.getManager().close(ps);
            this.freeConnection(connection);
        }
    }

            ps = connection.prepareStatement(sql,
                    ResultSet.TYPE_FORWARD_ONLY,
                    ResultSet.CONCUR_READ_ONLY);