java - SQLException - 未请求生成的键 (MySQL)

Question

我在为我的游戏制作新角色时收到此错误，在 CreateCharHandler 中它发送“saveToDb(false);”但是当我与另一个我手动创建的字符进行游戏时，我可以 saveToDb(true);没有错误。请帮忙，为什么会这样？

http://i56.tinypic.com/oh1pn5.png

SaveToDb 方法 http://pastebin.com/9sT5XBxp

第 3514 行是:

ResultSet rs = ps.getGeneratedKeys();

提前致谢!

Answer 1

您的 SQLException 明确指出:

You need to specify Statement.RETURN_GENERATED_KEYS to the Statement.executeUpdate() or Connection.prepareStatement().

这可以通过以下方式实现(在 Connection.prepareStatement() 方法上添加一个附加值):

String SQL = ""; //whatever my String is
PreparedStatement ps = connection.prepareStatement(SQL, Statement.RETURN_GENERATED_KEYS);
ps.setString(1, "value");
//Other necessary ps.setXXX() methods

//now update
ps.executeUpdate();

ResultSet rs = ps.getGeneratedKeys();

Statement.RETURN_GENERATED_KEYS 是这里的关键。

希望这对您有所帮助!

附言:Useful resource .

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@Charlie berg，因为你喜欢偷懒，我更改了你代码的第 13 行以包含 Statement.RETURN_GENERATED_KEYS:

ps = con.prepareStatement("INSERT INTO characters (level, fame, str, dex, luk, `int`, exp, hp, mp, maxhp, maxmp, sp, ap, gm, skincolor, gender, job, hair, face, map, meso, hpMpUsed, spawnpoint, party, buddyCapacity, messengerid, messengerposition, mountlevel, mounttiredness, mountexp, equipslots, useslots, setupslots, etcslots, monsterbookcover, watchedcygnusintro, vanquisherStage, dojopoints, lastDojoStage, finishedDojoTutorial, vanquisherKills, matchcardwins, matchcardlosses, matchcardties, omokwins, omoklosses, omokties, givenRiceCakes, partyquestitems, jailtime, accountid, name, world) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)", Statement.RETURN_GENERATED_KEYS);

此外，Statement 类属于 java.sql 包(确保导入正确)。 :-)