sql插入并返回自增主键

          Connection conn = ConnectionManager.getConnection();        try {            conn.setAutoCommit(false);           String brand_id=null;                sql = "INSERT INTO `ig_brand`(name,icon,description,brand_label) VALUES(?,?,?,?)";                PreparedStatement pstmt = conn.prepareStatement(sb2.toString(), Statement.RETURN_GENERATED_KEYS);                     pstmt.setString(1, brand);                     pstmt.setString(2, brand_logo);                     pstmt.setString(3, madein);                     pstmt.executeUpdate();                     //检索由于执行此 Statement 对象而创建的所有自动生成的键                     ResultSet rs = pstmt.getGeneratedKeys();                     if (rs.next()) {                         //知其仅有一列，故获取第一列                         brand_id = rs.getLong(1)+"";                     }                 sql = "UPDATE quick_order a SET a.`status` = 2, a.send_time = now()  WHERE a.brand_id=? and merchant_id=?";                int count = DbTools.executeUpdate(sql, DbTools.makeParams(express_number, brand_id, merchant_id));                  }        } catch (Exception e) {            e.printStackTrace();            try {                conn.rollback();            } catch (SQLException e1) {                e.printStackTrace();            }        } finally {            try {                conn.setAutoCommit(true);            } catch (SQLException e) {                e.printStackTrace();                throw new RuntimeException();            }            ConnectionManager.returnConnection(conn);        }