Java後臺-數據庫jdbc查找與插入操作

package com.xzy.dao;

import com.xzy.dao.FlowerDao;
import com.xzy.pojo.Flower;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class FlowerDaoImpl implements FlowerDao {
    public List<Flower> selAll(){
        List<Flower> list=new ArrayList<>();
        Connection conn=null;
        PreparedStatement ps=null;
        ResultSet rs=null;
        try{
            Class.forName("com.mysql.jdbc.Driver");
            conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/flower?serverTimezone=UTC&characterEncoding=utf-8","root","Xiao1234!");
            ps=conn.prepareStatement("select * from flower");
            rs=ps.executeQuery();//rs是一行數據,只要是jdbc，都是一行行通過遊標指引
            while(rs.next()){           //re,next() 將光標從當前位置向前移一行。
                list.add(new Flower(rs.getInt(1),rs.getString(2),rs.getDouble(3),rs.getString(4)));
            }
        }catch (ClassNotFoundException e){
            e.printStackTrace();
        }catch (SQLException e){
            e.printStackTrace();
        }finally {
            try {
                rs.close();
                ps.close();
                conn.close();
            }catch (SQLException e){
                e.printStackTrace();
            }
        }

        return list;
    }

    @Override
    public int insFlower(Flower flower) {
        int index=0;
        Connection conn=null;
        PreparedStatement ps=null;
        try{
            Class.forName("com.mysql.jdbc.Driver");
            conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/flower?serverTimezone=UTC&characterEncoding=utf-8","root","Xiao1234!");

            ps=conn.prepareStatement("insert into flower values (default ,?,?,?)");//!!!! default ?

            ps.setObject(1,flower.getName());
            ps.setObject(2,flower.getPrice());
            ps.setObject(3,flower.getProduction());

            index=ps.executeUpdate();
        }catch (ClassNotFoundException e){
            e.printStackTrace();
        }catch (SQLException e){
            e.printStackTrace();
        }finally {
            try {
                ps.close();
                conn.close();
            }catch (SQLException e){
                e.printStackTrace();
            }
        }
        return index;
    }
}