数据库连接-登录

public class Demo3 {
    public static void main(String[] args) throws SQLException, ClassNotFoundException {
        //1.注册驱动
        Class.forName("com.mysql.jdbc.Driver");
        //2.获取连接对象
        String url="jdbc:mysql://localhost:3306/day22_JDBC?characterEncoding=UTF-8";
        String username="root";
        String password="123456";
        Connection conn=DriverManager
                        .getConnection(url,username,password);
        //3.获取语句执行对象
        Statement sta=conn.createStatement();
        //让用户输入用户名和密码
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入用户名");
        String uname=sc.next();
        System.out.println("请输入密码");
        String pwd=sc.next();
    
        //4.执行sql
        //用户信息写死
        String sql="SELECT COUNT(*) FROM USER WHERE uname='"+uname+"' AND pwd='"+pwd+"'";
        //
        //
        ResultSet rs=sta.executeQuery(sql);
        //5.处理结果集
        //
        int count=0;
        while(rs.next()){
            count=rs.getInt(1);
        }
        if(count>0){
            System.out.println("登陆成功~");
        }
        else{
            System.out.println("登陆失败~");
            
        }
        //6.释放资源
        rs.close();
        sta.close();
        conn.close();
    }
}

public class Demo3 {public static void main(String[] args) throws SQLException, ClassNotFoundException {//1.注册驱动Class.forName("com.mysql.jdbc.Driver");//2.获取连接对象String url="jdbc:mysql://localhost:3306/day22_JDBC?characterEncoding=UTF-8";String username="root";String password="123456";Connection conn=DriverManager.getConnection(url,username,password);//3.获取语句执行对象Statement sta=conn.createStatement();//让用户输入用户名和密码Scanner sc=new Scanner(System.in);System.out.println("请输入用户名");String uname=sc.next();System.out.println("请输入密码");String pwd=sc.next();//4.执行sql//用户信息写死String sql="SELECT COUNT(*) FROM USER WHERE uname='"+uname+"' AND pwd='"+pwd+"'";////ResultSet rs=sta.executeQuery(sql);//5.处理结果集//int count=0;while(rs.next()){count=rs.getInt(1);}if(count>0){System.out.println("登陆成功~");}else{System.out.println("登陆失败~");}//6.释放资源rs.close();sta.close();conn.close();}}