import java.util.*;

import java.sql.*;

public class FruitDao {

    private Connection conn;

    private PreparedStatement pre;

    private ResultSet rs;

    public FruitDao() throws Exception {

        conn = DBConnection.aa();

    }

    //返回总页数

    public int yeshu(int meiyegeshu) throws SQLException{

        //求有多少行

        int yeshu = 0;

        String sql = "select count(*)from fruit";

        pre = conn.prepareStatement(sql);

        rs = pre.executeQuery();

        rs.next();

        int hangshu = rs.getInt(1);

        //求有多少页

        yeshu = (int)Math.ceil(1.0*hangshu/meiyegeshu);//取上限值

        conn.close();

        return yeshu;

    }

    //返回指定页的数据

    public ArrayList<Fruit> selest(int yaozhaoyeshu,int meiyegeshu) throws Exception{

        ArrayList<Fruit> list = new ArrayList<Fruit>();

        String sql = "select * from fruit limit ?,?";

        pre = conn.prepareStatement(sql);

        pre.setInt(1, meiyegeshu*(yaozhaoyeshu-1));//要找第几页，从多少行开始

        pre.setInt(2, meiyegeshu);//找的页有多少行

        rs = pre.executeQuery();

        while (rs.next()){

            Fruit data = new Fruit();

            data.setIds(rs.getString(1));

            data.setName(rs.getString(2));

            data.setPrice(rs.getDouble(3));

            data.setSource(rs.getString(4));

            data.setNumbers(rs.getInt(5));

            data.setImage(rs.getString(6));

            list.add(data);

        }

        conn.close();

        return list;

    }

}