java 使用 JDBC PreparedStatement 在 MySql 中返回生成的键
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Returning generated keys in MySql with JDBC PreparedStatement
提问by Paul Vargas
I'm programming with plain JDBCa DAOlayer because I only have 61.38 MBon Java Memoryin my Tomcat(service hosting). I have a table with an AUTO_INCREMENTcolumn in MySQL. The current implementation has no problems. But I would like to know the value that was generated in the AUTO_INCREMENTcolumn.
我用普通的编程JDBC一个DAO层，因为我只有 61.38 MB对Java内存在我的Tomcat（服务主机）。我AUTO_INCREMENT在 MySQL 中有一个包含一列的表。当前的实现没有问题。但我想知道AUTO_INCREMENT列中生成的值。
The current code looks as follows in the method that inserts a new row.
当前代码在插入新行的方法中如下所示。
public Integer store(MyBean bean) throws DAOException {
Connection conn = null;
PreparedStatement ps = null;
try {
conn = getConnection();
ps = conn.prepareStatement("INSERT ...");
if (bean.getSomeProperty() != null) {
ps.setShort(1, bean.getSomeProperty());
} else {
ps.setNull(1, Types.SMALLINT);
}
/* Other fields */
int rows = ps.executeUpdate();
if (rows == 1) {
// RETURN the generated value
}
return null;
} catch (SQLException e) {
throw new DAOException(e);
} finally {
...
}
}
I have seen that this is possible in Hibernate, but because I have little memory, is not a feasible option.
我已经看到这在 中是可能的Hibernate，但是因为我的记忆力很小，所以不是一个可行的选择。
I appreciate the help.
我很感激你的帮助。
回答by Mark Rotteveel
There are two ways:
有两种方式：
Using the JDBC concept of
getGeneratedKeys(). See http://dev.mysql.com/doc/connector-j/en/connector-j-usagenotes-last-insert-id.html#connector-j-examples-autoincrement-getgeneratedkeysOr use the MySQL function
LAST_INSERT_ID(). See http://dev.mysql.com/doc/connector-j/en/connector-j-usagenotes-last-insert-id.html#connector-j-examples-autoincrement-select
使用 JDBC 概念
getGeneratedKeys(). 请参阅http://dev.mysql.com/doc/connector-j/en/connector-j-usagenotes-last-insert-id.html#connector-j-examples-autoincrement-getgeneratedkeys或者使用 MySQL 函数
LAST_INSERT_ID()。见http://dev.mysql.com/doc/connector-j/en/connector-j-usagenotes-last-insert-id.html#connector-j-examples-autoincrement-select
