package dao.impl; import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.handlers.BeanHandler; import utils.JdbcUtils; import dao.AdminDao; import domain.Admin; public class AdminDaoImpl implements AdminDao { public Admin find(String username, String password){ try{ QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource()); String sql = "select * from admin where username=? and password=?"; Object params[] = {username, password}; return (Admin)runner.query(sql, params, new BeanHandler(Admin.class)); } catch(Exception e){ throw new RuntimeException(e); } } }帮我把这段代码加一下注释

package dao.impl;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;

import utils.JdbcUtils;
import dao.AdminDao;
import domain.Admin;

public class AdminDaoImpl implements AdminDao {

    // 根据用户名和密码查找管理员信息
    public Admin find(String username, String password){
        try{
            QueryRunner runner = new QueryRunner(JdbcUtils.getDataSource()); // 创建QueryRunner对象
            String sql = "select * from admin where username=? and password=?"; // SQL查询语句
            Object params[] = {username, password}; // 查询参数
            return (Admin)runner.query(sql, params, new BeanHandler(Admin.class)); // 执行查询并返回结果
        } catch(Exception e){
            throw new RuntimeException(e); // 抛出运行时异常
        }
    }

}

这段代码实现了根据用户名和密码查询管理员信息的功能。首先创建了一个QueryRunner对象，然后定义了SQL查询语句和查询参数。最后通过调用QueryRunner对象的query方法执行查询，并返回结果。