用户登录模拟

工具：mysql 5.7 Navicat for MySQL eclipse
User
数据库设计：

---

username varchar(10)
password varchar(10)

create database User;
create table user(
    username varchar(10) not null,
    password varchar(10) not null
);
insert into user values('2012015358','123456');
select * from user;

Java代码:

package com.pengmin.test;

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

import com.mysql.jdbc.Driver;
import com.pengmin.util.DBUtils;

public class UserTest {
    public static void main(String[] args) {
        Connection conn = null;
        Statement stat = null;
        ResultSet rs = null;
        Scanner sc = new Scanner(System.in);
        // 注册驱动
        try {
            DriverManager.registerDriver(new Driver());
            // 建立连接
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/User", "root", "123456");
            System.out.println("请输入用户名：");
            String username = sc.next();
            System.out.println("请输入密码：");
            String password = sc.next();
            // 定义sql语句
            String sql = "select * from user " + "where username='" + username + "' and password='" + password + "'";
            // 创建发送sql语句的容器
            stat = conn.createStatement();
            // 查询并返回结果集
            rs = stat.executeQuery(sql);
            // System.out.println(rs.next());
            if (rs.next()) {
                System.out.println("登录成功");
            } else {
                System.out.println("登录未成功");
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
                DBUtils.close(conn, stat, rs);
        }
    }
}