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;
}
}