[java/jdbc]插入数据时获取自增长主键的值
需求
数据库中的unum字段为自增长主键，使用sql语句插入时需要获取主键的值
insert into udata(upwd,utime,upath) values(?,?,?)插入之后再查找显然效率太慢，其实jdbc提供了getGeneratedKeys()方法来获取主键
代码
PreparedStatement ps = conn.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS);
ps.setObject(1,XXX);
.....
int rs=ps.executeUpdate();ResultSet generatedKeys = ps.getGeneratedKeys();
if (generatedKeys.next()) {unum=generatedKeys.getInt(1); //得到主键
}
说明
如果报异常
Generated keys not requested. You need to specify Statement.RETURN_GENERATED_KEYS to Statement.execu
mysql-connector包在5.1.17之后需要在prepareStatement里加上额外参数(Statement.RETURN_GENERATED_KEYS或Statement.NO_GENERATED_KEYS)
ps = conn.prepareStatement(sql,PreparedStatement.RETURN_GENERATED_KEYS);