resultset-->executeQuery

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class Demo3 {
    public static void main(String[] args) throws Exception {
        //1.注册驱动
        Class.forName("com.mysql.jdbc.Driver");
        //2.获取连接对象//url数据库
        Connection connection= DriverManager.getConnection("jdbc:mysql://localhost:3306/demo","root","root");
        //3.获取执行SQL语句的对象
        Statement statement=connection.createStatement();
        //4.执行SQL语句，
        //resultset以表结构进行临时结果存储，要通过jdbc api 将其依次获取
        ResultSet resultSet= statement.executeQuery("select *from user");
        //5.处理结果
        while(resultSet.next()){//判断下一行是否有数据；
            //对当前列编号数据进行获取，根据列的编号
            int id= resultSet.getInt(1);
            String username= resultSet.getString(2);
            String password= resultSet.getString(3);
            System.out.println(id+"\t"+username+"\t"+password);
        }
        //6.释放资源
        resultSet.close();
        statement.close();
        connection.close();
    }
}