package finalexam.Database; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Scanner; public class UserLogin { private static final String DBDRIVER = "com.mysql.cj.jdbc.Driver"; private static final String DBURL = "jdbc:mysql://localhost:3306/xiaoshou?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT"; public static void main(String[] args) throws Exception { Class.forName(DBDRIVER); Connection conn = DriverManager.getConnection(DBURL); PreparedStatement pstmt = null; ResultSet rs = null; Scanner scanner = new Scanner(System.in); int attempts = 0; boolean loginSuccess = false; while (attempts < 3 && !loginSuccess) { System.out.println("欢迎使用阳光超市收银系统,请登陆"); System.out.print("请输入用户名: "); String username = scanner.nextLine(); System.out.print("请输入密码: "); String password = scanner.nextLine(); String sql = "SELECT xingming FROM t_yong WHERE yonghuming=? AND mima=?"; pstmt = conn.prepareStatement(sql); pstmt.setString(1, username); pstmt.setString(2, Encrypt.MD5(password)); rs = pstmt.executeQuery(); if (rs.next()) { loginSuccess = true; String xingming = rs.getString("xingming"); SimpleDateFormat formatter = new SimpleDateFormat("yyyy年MM月dd日HH时mm分ss秒"); String currentTime = formatter.format(new Date()); System.out.println("欢迎使用阳光超市收银系统"); System.out.println("当前收银员:" + xingming); System.out.println("当前时间:" + currentTime); } else { System.out.println("用户名或密码不正确,请重新输入"); attempts++; } } if (!loginSuccess) System.out.println("最多只能尝试3次"); rs.close(); pstmt.close(); conn.close(); } }