登录案例练习

分析：

1. 创建数据库表
   

2. 设计

package cn.itcast.jdbc;

import util.JDBCUtils;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Scanner;


public class login {

    public static void main(String[] args) {
        //键盘输入，接受用户名和密码
        Scanner sc = new Scanner(System.in);
        System.out.println("用户名：");
        String username = sc.nextLine();
        System.out.println("密码：");
        String password = sc.nextLine();
        //调用方法
        boolean flag = new login().login(username, password);
        //判断结果，输出不同语句
        if(flag){
            System.out.println("登陆成功！");
        }else{
            System.out.println("用户名或密码错误。");
        }
    }

    
    public boolean login(String username,String password){
        if(username==null || password==null){
            return false;
        }
        //连接数据库判断是否登录成功
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        
        try {
            conn = JDBCUtils.getConnection();
            String sql = "select * from user where username='"+ username +"' and password='"+ password +"'";
            stmt = conn.createStatement();
            rs = stmt.executeQuery(sql);
            return rs.next();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            JDBCUtils.close(rs,stmt,conn);
        }

        return false;
    }
}

运行结果：

优化后：文章指路