PreparedStatement连接数据库实现登录验证，避免sql注入问题

package d03_system;

import java.sql.*;
import java.util.Scanner;

/**
 * zt
 * 2020/8/20
 * 14:19
 * 1.注册驱动（可省略）
 * 2.创建链接
 * 3.创建命令
 * 4.执行命令
 * 5.关闭资源
 *
 * PreparedStatement pstat = conn.prepareStatement("select * from user where name=? and password=?");避免sql注入，出现（大明' or 1=1;#）错误
 */
public class Login {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        System.out.println("------------------欢迎登录-------------------");
        System.out.println("请输入你的用户名 （づ￣3￣）づ╭❤～");
        String username = sc.nextLine();
        System.out.println("请输入你的密码 ︿(￣︶￣)︿");
        String password = sc.nextLine();

        //1.注册驱动
        Class.forName("com.mysql.jdbc.Driver");
        //2.创建链接
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/gp2002?useSSL=false&characterEncoding=utf8", "root", "root");
        //3.创建命令
//        Statement stat = conn.createStatement();
        //3.1?占位符，执行时会替换为实际数据(自动转译不会出现sql注入)
        PreparedStatement pstat = conn.prepareStatement("select * from user where name=? and password=?");
        //3.2给占位符赋值
        pstat.setString(1, username);
        pstat.setString(2, password);
        ResultSet rs = pstat.executeQuery();
        //4.执行命令
//        ResultSet rs = stat.executeQuery("select * from user where name='" + username + "' and password ='" + password + "';");

        //5.遍历
        if(rs.next()){
            System.out.println("登陆成功ヽ(✿ﾟ▽ﾟ)ノ");
        }else{
            System.out.println("登陆失败Σ( ° △ °|||)︴");
        }

        /*ResultSet rs = stat.executeQuery("select name,password from user;");
        while(rs.next()) {
            String name1 = rs.getString("name");
            String password1 = rs.getString("password");
            if (name1.equals(username) && password1.equals(password)) {
                    System.out.println("登陆成功ヽ(✿ﾟ▽ﾟ)ノ");
                    break;
//                    return;
            } else {
                System.out.println("登陆失败Σ( ° △ °|||)︴");
            }
        }*/


        //6.关闭
        rs.close();
        pstat.close();
        conn.close();



    }
}

------------------欢迎登录-------------------
请输入你的用户名 （づ￣3￣）づ╭❤～
saf' or 1=1;#
请输入你的密码 ︿(￣︶￣)︿
4564
登陆失败Σ( ° △ °|||)︴

Process finished with exit code 0