1 public int add(SalesOrder so) { 2 int orderId = -1; 3 DB db = new DB(); 4 Connection connection = db.getConn(); 5 boolean autoCommit = true; 6 try { 7 autoCommit = connection.getAutoCommit();//将默认的提交方式先记下来,以恢复现场用 8 connection.setAutoCommit(false); 9 } catch (SQLException e1) { 10 // TODO Auto-generated catch block 11 e1.printStackTrace(); 12 } 13 String sql = "insert into SalesOrder(uid,status) values(?,?)"; 14 try { 15 // 订单写入数据库 16 PreparedStatement ps = connection.prepareStatement(sql, 17 Statement.RETURN_GENERATED_KEYS);//在添加订单的同时,获得该订单的自动生成的id 18 ps.setInt(1, so.getCustomer().getCid()); 19 ps.setInt(2, so.getStatus()); 20 ps.executeUpdate(); 21 22 // 获得自动生成的新订单号 23 ResultSet rsKey = ps.getGeneratedKeys(); 24 rsKey.next(); 25 orderId = rsKey.getInt(1); 26 27 // 将所有的订单项写入数据库 28 String sqlItem = "insert into salesItem(pid,pcount,oid) values(?,?,?)"; 29 PreparedStatement psItem = connection.prepareStatement(sqlItem); 30 List<SalesItem> items = so.getItems(); 31 Iterator<SalesItem> it = items.iterator(); 32 while (it.hasNext()) { 33 SalesItem item = it.next(); 34 psItem.setInt(1, item.getItem().getProduct().getPid()); 35 psItem.setInt(2, item.getItem().getCount()); 36 psItem.setInt(3, orderId); 37 psItem.addBatch();//将每个订单项添加操作加入批处理作业中 38 } 39 psItem.executeBatch();//执行批处理 40 connection.commit();//手动提交数据库 41 ps.close(); 42 psItem.close(); 43 44 } catch (SQLException e) { 45 try { 46 connection.rollback(); 47 } catch (SQLException e1) { 48 e1.printStackTrace(); 49 } 50 e.printStackTrace(); 51 } finally { 52 try { 53 connection.setAutoCommit(autoCommit); 54 connection.close(); 55 db.close(); 56 } catch (SQLException e) { 57 e.printStackTrace(); 58 } 59 } 60 return orderId; 61 }
这样做的目的就是只有在我们成功添加新订单后,才可以将购物项加入该订单。以保持数据的一致性
ps:
commit的作用:就是把緩沖區的數據提交到數據庫
autocommit=true就是你無須執行commit,程序就自動幫你執行
autocommit=false,直到你commit或disconnect才執行commit
时间: 2024-11-13 08:57:03