package com.itheima.login.dao;



import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.Statement;



import com.itheima.login.domain.User;

import com.itheima.login.utils.JdbcUtils;



public class UserDao {



	//查询 单个 用户 , 这里 是dao的核心类, 封装了对数据源 的操作

	public User selectOne(User user) {

		

		

		Connection conn = null;

		PreparedStatement stmt = null;

		ResultSet rs = null;

		try {

			

//			获得链接

			conn = JdbcUtils.getConnection();

			

			// ? 表示占位符 

			String sql ="select * from users where username=? and password=?";

			

			//获得PreparedStatement对象

			stmt = conn.prepareStatement(sql);

			

			//替换占位符

			stmt.setString(1, user.getUsername());

			stmt.setString(2, user.getPassword());

			

			

			//拿到结果集

			rs = stmt.executeQuery();

			User loginUser = null;

			

			//解析结果集 

			if(rs.next()){

				

				loginUser = new User();

				int id = rs.getInt("id");

				String username = rs.getString("username");

				String password = rs.getString("password");

				String nickname = rs.getString("nickname");

				

				//封装登录用户的信息

				loginUser.setId(id);

				loginUser.setUsername(username);

				loginUser.setPassword(password);

				loginUser.setNickname(nickname);

				

			}

			

			return loginUser;

			

		} catch (Exception e) {

			e.printStackTrace();

			return null;

		}finally{

			

			

			JdbcUtils.release(rs, stmt, conn);

		}

		

	}

	//查询 单个 用户 , 这里 是dao的核心类, 封装了对数据源 的操作

	public User selectOne1(User user) {

		

		

		Connection conn = null;

		Statement stmt = null;

		ResultSet rs = null;

		try {

			

//			获得链接

			conn = JdbcUtils.getConnection();

			

			//获得statement对象

			stmt = conn.createStatement();

			

			// select * from users where username='' and password='';

			String sql = "select * from users where username='"+user.getUsername()+"' and password='"+user.getPassword()+"'";

			

			// select * from users where username='hehui' or '1'='1' and password='';

			//拿到结果集

			rs = stmt.executeQuery(sql);

			

			User loginUser = null;

			//解析结果集 

			if(rs.next()){

				

				loginUser = new User();

				int id = rs.getInt("id");

				String username = rs.getString("username");

				String password = rs.getString("password");

				String nickname = rs.getString("nickname");

				

				//封装登录用户的信息

				loginUser.setId(id);

				loginUser.setUsername(username);

				loginUser.setPassword(password);

				loginUser.setNickname(nickname);

				

			}

			

			return loginUser;

			

		} catch (Exception e) {

			e.printStackTrace();

			return null;

		}finally{

			

			

			JdbcUtils.release(rs, stmt, conn);

		}

		

	}



}