获得数据库自动生成的主键

package cn.itcast.jdbc;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import org.junit.Test;
import cn.itcast.utils.JdbcUtils;
/*
create table test1(
id int primary key auto_increment,
name varchar(100)
);
*/
public class Demo4 {
@Test
public void test1() throws Exception{
Connection conn =null;
PreparedStatement st =null;
ResultSet rs =null;
try
{
conn  =JdbcUtils.getConnection();
String sql= "insert into test1(name) values (?)";
st =conn.prepareStatement(sql);
st.setString(1,"aaa");
st.executeUpdate();
//下面的ResultSet中封装了数据库自动生成的id
rs=st.getGeneratedKeys();
if(rs.next()){
System.out.println(rs.getInt(1));
}
}catch (Exception e){
e.printStackTrace();
}finally{
JdbcUtils.release(conn, st, rs);
}
}
}