MySQL & Java-获取上一个插入值(JDBC)的 id

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如何在 JDBC 中获取插入 ID

嗨，我正在使用 JDBC 通过 Java 连接数据库。

现在，我执行一些插入查询，并且需要获取上次插入值的 id (因此，在 stmt.executeUpdate之后)。

我不需要像 SELECT id FROM table ORDER BY id DESC LIMIT 1这样的东西，因为我可能有并发性问题。

我只需要检索与最后一次插入相关联的 id (关于我的语句实例)。

我试过这种方法，但似乎在 JDBC 上不起作用:

public Integer insertQueryGetId(String query) {
Integer numero=0;
Integer risultato=-1;
try {
Statement stmt = db.createStatement();
numero = stmt.executeUpdate(query);


ResultSet rs = stmt.getGeneratedKeys();
if (rs.next()){
risultato=rs.getInt(1);
}
rs.close();


stmt.close();
} catch (Exception e) {
e.printStackTrace();
errore = e.getMessage();
risultato=-1;
}
return risultato;
}

事实上，每次 risultato = -1，我得到 java.sql.SQLException: Generated keys not requested. You need to specify Statement.RETURN_GENERATED_KEYS to Statement.executeUpdate() or Connection.prepareStatement().

我该如何解决这个问题

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最佳答案

Wouldn't you just change:

numero = stmt.executeUpdate(query);

to:

numero = stmt.executeUpdate(query, Statement.RETURN_GENERATED_KEYS);

Take a look at the documentation for the JDBC Statement interface.

Update: Apparently there is a lot of confusion about this answer, but my guess is that the people that are confused are not reading it in the context of the question that was asked. If you take the code that the OP provided in his question and replace the single line (line 6) that I am suggesting, everything will work. The numero variable is completely irrelevant and its value is never read after it is set.

小开

Alternatively you can do:

Statement stmt = db.prepareStatement(query, Statement.RETURN_GENERATED_KEYS);
numero = stmt.executeUpdate();


ResultSet rs = stmt.getGeneratedKeys();
if (rs.next()){
risultato=rs.getString(1);
}

But use Sean Bright's answer instead for your scenario.


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