import java.io.PrintWriter;
import java.sql.*;

public class Main {
    public static void main(String[] args) {
        try (
                Connection connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/study","root","123456");
                Statement statement = connection.createStatement();
        ){
            int i = statement.executeUpdate("insert into student values(4,'monkey','男')");
            // statement.executeUpdate("delete from student where sid = 4");
            // int i = statement.executeUpdate("update student set name = 'dog' where sid=3");
            System.out.println("生效了："+i+"行");
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
}

try (Connection connection = DriverManager.getConnection("URL","用户名","密码");
     Statement statement = connection.createStatement();
     Scanner scanner = new Scanner(System.in)){
    ResultSet res = statement.executeQuery("select * from user where username='"+scanner.nextLine()+"'and pwd='"+scanner.nextLine()+"';");
    while (res.next()){
        String username = res.getString(1);
        System.out.println(username+" 登陆成功！");
    }
}catch (SQLException e){
    e.printStackTrace();
}