public interface Command {
    public void execute();
}

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

public class PrepareQueryCommand implements Command {

    @Override
    public void execute() {
        System.out.println("请输入商品价格查询的最大值：");
        Scanner sc=new Scanner(System.in);
        float max=sc.nextFloat();
        //1、加载并注册JDBC驱动
        Connection conn=null;
        PreparedStatement pstmt=null;
        ResultSet rs=null;
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2、创建数据库连接
            String url="jdbc:mysql://localhost:3306/jdbc?useSSL=false&useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&allowPublicKeyRetrieval=true";
            conn=DriverManager.getConnection(url,"root","root");
            //3、创建PreparedStatement对象
            String sql="select * from goods where price<=?";
            pstmt=conn.prepareStatement(sql);
            pstmt.setFloat(1,max);
            rs=pstmt.executeQuery();
            //4、遍历查询结果
            int count=1;
            System.out.printf("%-4s%-6s%-5s%-7s%-10s","序号","商品id","商品名称","商品价格","商品描述");
            System.out.println();
            while(rs.next()){
                int id=rs.getInt(1);
                String name= rs.getString(2);
                float price=rs.getFloat(3);
                String desp=rs.getString(4);
                System.out.printf("%-5s%-7s%-7s%-10s%-10s",count,id,name,price,desp);
                System.out.println();
                count++;
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }finally {
            //5、关闭连接，释放资源
            try {
                if (rs!=null){
                    rs.close();
                }
                if (pstmt!=null){
                    pstmt.close();
                }
                if (conn!=null&&!conn.isClosed()){
                    conn.close();
                }
            } catch (SQLException ex) {
                ex.printStackTrace();
            }

        }
    }
}

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class GoodsQuery {
public static void main(String[] args) {
Command command=new PrepareQueryCommand();
command.execute();
    }
}