Question

我在使用Java的PreparedStatements尝试将列插入数据库时锁定等待超时的情况下感到困惑，但如果我使用MySQL执行此操作，则不会遇到类似的问题

我正在处理的两个表名为项和 inventory_items 。 Inventory_items具有对 inventoryitemid 列的项目的外键引用。

我目前在Java中使用的是对项目进行批量插入，然后获取返回的密钥，然后将相关信息插入inventory_items。还有其他表对项目具有相同的外键引用，但是对于这种情况，如果我可以修复项目和inventory_items之间的问题，那么我确定我可以为其余部分修复它。

inventory_items

的表格结构

CREATE TABLE `inventory_items` (
  `inventoryitemid` int(11) unsigned NOT NULL,
  `characterid` int(11) DEFAULT NULL,
  `inventorytype` int(11) NOT NULL DEFAULT '0',
  PRIMARY KEY (`inventoryitemid`),
  KEY `charid` (`characterid`),
  CONSTRAINT `INVENTORYITEM_FK` FOREIGN KEY (`inventoryitemid`) REFERENCES `items` (`inventoryitemid`) ON DELETE CASCADE ON UPDATE NO ACTION
) ENGINE=InnoDB DEFAULT CHARSET=latin1

项目的表格结构

CREATE TABLE `items` (
  `inventoryitemid` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `itemid` int(11) NOT NULL DEFAULT '0',
  `quantity` int(11) NOT NULL DEFAULT '0',
  `owner` tinytext NOT NULL,
  `petid` int(11) NOT NULL DEFAULT '-1',
  `flag` int(11) NOT NULL,
  `expiration` bigint(20) NOT NULL DEFAULT '-1',
  `giftFrom` varchar(26) NOT NULL,
  `position` tinyint(4) DEFAULT NULL,
  PRIMARY KEY (`inventoryitemid`)
) ENGINE=InnoDB AUTO_INCREMENT=733 DEFAULT CHARSET=latin1

项目图片

inventory_items的图片

Java Prepared Statement（超时）

con.prepareStatement("INSERT INTO inventory_items (inventoryitemid, characterid, inventorytype) VALUES (?, ?, ?)");

MySQL等价物

INSERT INTO inventory_items (inventoryitemid, characterid, inventorytype) VALUES (730, 38843, 3)

请注意，我已经输入了SQL语句中的实际值，以查看它是否可以插入。

完整Java SQL代码

@Override
        public void batch(Pair<Item, MapleInventoryType> entry, int key, int id) {
            try {
                if (ps.isClosed())
                    ps = con.prepareStatement("INSERT INTO inventory_items (inventoryitemid, characterid, inventorytype) VALUES (?, ?, ?)");
                //System.out.println("Batching! " + ps.isClosed());
                System.out.println("KEY IS " + key);
                ps.setInt(1, key);
                ps.setInt(2, id);
                ps.setInt(3, entry.getRight().getType());
                ps.addBatch();
            } catch (Exception e) {
                LogHelper.GENERAL_EXCEPTION.get().info("InventoryWorker batch: " + e);
            }

        }

        @Override
        public void executeBatch(int id) throws SQLException {
            // TODO Auto-generated method stub
            try (PreparedStatement delete = con.prepareStatement("DELETE FROM items WHERE EXISTS (SELECT * FROM inventory_items WHERE inventory_items.inventoryitemid = items.inventoryitemid AND characterid = ?)")) {
                System.out.println("DELETE BY " + id); 
                delete.setInt(1, id);
                delete.execute(); 

                if (!ps.isClosed()) {
                    ps.executeBatch();
                }
            } catch (SQLException e) {
                LogHelper.GENERAL_EXCEPTION.get().info("InventoryWorker executeBatch: " + e);
            } finally {
                ps.close();
            }
        }

我将它拆分为两种方法的原因是因为我正在进行不同类型的节省，所以我将保存拆分为类来处理保存类型。我不认为我们应该关注准备好的语句永远不会关闭的可能性，因为我在这个范围之外有一个finally子句，只是在异常的情况下关闭所有内容。

调用上述2种方法的整个save子句。 请注意，这两个方法位于名为 worker 的类下。在代码中，它将被称为 worker.batch（）和 worker.executeBatch（）

    public void saveItems(List<Pair<Item, MapleInventoryType>> items, int id, Connection con) throws SQLException {
        lock.lock();
        long start = System.currentTimeMillis();
//        StringBuilder query = new StringBuilder();
//        query.append(
//                "UPDATE `inventoryitems` SET characterid = -1 WHERE `");
//        query.append(account ? "accountid" : "characterid").append("` = ? AND `type` = ? LIMIT 128");
        try {
//            try (PreparedStatement ps = con.prepareStatement(query.toString())) {                
//                ps.setInt(1, id);
//                ps.setInt(2, value);
//                ps.executeUpdate();
//            } catch (Exception e) {
//              LogHelper.GENERAL_EXCEPTION.get().info("ItemFactory updateItems: " + e);
//            }
            System.out.println("Time to delete items " + (System.currentTimeMillis() - start));
            start = System.currentTimeMillis();
            try (PreparedStatement ps = con.prepareStatement("INSERT INTO `items` (`itemid`"+
                    ", `quantity`, `owner`, `petid`, `flag`, `expiration`, `giftFrom`, `position`) VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
                 Statement.RETURN_GENERATED_KEYS);
                 PreparedStatement pse = con.prepareStatement(
                 "INSERT INTO `inventoryequipment` (`inventoryequipmentid`, `inventoryitemid`, `upgradeslots`, `level`, `str`, `dex`, `int`"+
                 ", `luk`, `hp`, `mp`, `watk`, `matk`, `wdef`, `mdef`, `acc`, `avoid`, `hands`, `speed`, `jump`, `vicious`, `itemLevel`, `itemexp`, `ringid`, `skill`) VALUES (DEFAULT, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)");
                ) {

                LinkedList<Pair<Item, MapleInventoryType>> saved_items = new LinkedList<>();

                if (!items.isEmpty()) {
                    for (Pair<Item, MapleInventoryType> pair : items) {
                        Item item = pair.getLeft();
                        if (item.disappearsAtLogout())
                            continue;
                        MapleInventoryType mit = pair.getRight();
                        ps.setInt(1, item.getItemId());
                        ps.setInt(2, item.getQuantity());
                        ps.setString(3, item.getOwner());
                        ps.setInt(4, item.getPetId());
                        ps.setInt(5, item.getFlag());
                        ps.setLong(6, item.getExpiration());
                        ps.setString(7, item.getGiftFrom());
                        ps.setInt(8, item.getPosition());
//                        ps.setInt(1, value);
//                        ps.setString(2, account ? null : String.valueOf(id));
//                        ps.setString(3, account ? String.valueOf(id) : null);
//                        ps.setInt(4, item.getItemId());
//                        ps.setInt(5, mit.getType());
//                        ps.setInt(6, item.getPosition());
//                        ps.setInt(7, item.getQuantity());
//                        ps.setString(8, item.getOwner());
//                        ps.setInt(9, item.getPetId());
//                        ps.setInt(10, item.getFlag());
//                        ps.setLong(11, item.getExpiration());
//                        ps.setString(12, item.getGiftFrom());
                        saved_items.add(pair);
                        ps.addBatch();
                    }

                    ps.executeBatch();
                    System.out.println("Time to save items " + (System.currentTimeMillis() - start));
                    start = System.currentTimeMillis();
                    System.out.println("RIGHT BEFORE EQUIPMENT");
                    try (ResultSet rs = ps.getGeneratedKeys()) {
                        for (Pair<Item, MapleInventoryType> item : saved_items) {  
                            int key = -1;
                            if (rs.next()) {                            
                                key = rs.getInt(1);
                            }

                            if (key == 0) {
                                key = item.getLeft().getInventoryItemId();
                            }

                            worker.batch(item, key, id);
                            MapleInventoryType mit = item.right; 
                            if (mit.equals(MapleInventoryType.EQUIP) || mit.equals(MapleInventoryType.EQUIPPED)) {
                                pse.setInt(1, key);
                                Equip equip = (Equip) item.left;
                                pse.setInt(2, equip.getUpgradeSlots());
                                pse.setInt(3, equip.getLevel());
                                pse.setInt(4, equip.getStr());
                                pse.setInt(5, equip.getDex());
                                pse.setInt(6, equip.getInt());
                                pse.setInt(7, equip.getLuk());
                                pse.setInt(8, equip.getHp());
                                pse.setInt(9, equip.getMp());
                                pse.setInt(10, equip.getWatk());
                                pse.setInt(11, equip.getMatk());
                                pse.setInt(12, equip.getWdef());
                                pse.setInt(13, equip.getMdef());
                                pse.setInt(14, equip.getAcc());
                                pse.setInt(15, equip.getAvoid());
                                pse.setInt(16, equip.getHands());
                                pse.setInt(17, equip.getSpeed());
                                pse.setInt(18, equip.getJump());
                                pse.setInt(19, equip.getVicious());
                                pse.setInt(20, equip.getItemLevel());
                                pse.setInt(21, equip.getItemExp());
                                pse.setInt(22, equip.getRingId());
                                pse.setBoolean(23, equip.hasSkill());
                                pse.addBatch(); 
                            }
                        }
                        pse.executeBatch();
                    }
                }
                worker.executeBatch(id);
            }
            System.out.println("Time to save equipment " + (System.currentTimeMillis() - start));
        } catch (Exception e) {
            LogHelper.GENERAL_EXCEPTION.get().info("ItemFactory saveItems: " + e);
        } finally {
            worker.close();
            lock.unlock();
        }
    }

为什么这个PreparedStatement在MySQL而不是Java中工作

0 个答案: