Javaweb新手入门案例 数据库连接登录注册

package com.binglian.dao; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import com.binglian.utils.MD5Utils; import com.binglian.utils.MySQLUtils; /** * 创建作者:冰怜 * 创建时间:2018/12/25 16:50 */ public class UserDao { //�����û��������û����� public String findUser(String username){ String psw=null; String sql="select * from user where username=?"; Connection con =MySQLUtils.getConnection(); PreparedStatement pstmt=null; ResultSet rs=null; try{ pstmt=con.prepareStatement(sql);//�������ݿ����� pstmt.setString(1, username);//��Ӧ��1���������û��� username rs=pstmt.executeQuery();//ִ��SQL��� ���ѷ������ݸ����ؼ� if (rs.next()) {//�ж�rsָ����û�����ݣ�Ȼ���ȡ���� psw=rs.getString("password"); } }catch (SQLException e) { e.printStackTrace(); }finally { try{ if(pstmt !=null) pstmt.close();//�ر����ݿ����� if(con !=null) con.close(); }catch (SQLException e) { e.printStackTrace(); } } return psw; } //����û� public void addUser(String username,String password){ Connection con=MySQLUtils.getConnection(); PreparedStatement pstmt=null; String sql="INSERT INTO user(username,password,createTime) VALUES(?,?,?)"; try { pstmt=con.prepareStatement(sql);//��ȡ�������ӣ� pstmt.setString(1, username);//һһ��Ӧ�ɴ�������username��password����ӵ����ݿ����һһ��Ӧ pstmt.setString(2, MD5Utils.md5(password)); pstmt.setDate(3, new java.sql.Date(System.currentTimeMillis()));//��ΪҪ����ʱ�䣬��������Ҫ����� pstmt.executeUpdate();//ִ�����ݿ���� } catch (SQLException e) { e.printStackTrace(); }finally{ try{ if (pstmt !=null) pstmt.close(); if(con!=null) con.close(); }catch (SQLException e) { e.printStackTrace(); } } } public static void main(String[] aegs){ //���Է��� System.out.println(new UserDao().findUser("11")); new UserDao().addUser("1123456", "123456"); } }