CSV类如何与模型类连接

Question

我有一个CSV类，可以读取和写入CSV文件。 我有一个模型类User，我想要一个方法，该方法通过ID（getUserById）从CSV返回我一个User对象； 因此，CSV应该返回User类对象。 问题是我希望CSV从Book对象调用时也返回Book对象。

我阅读了有关DI和反射的信息，但我不明白如何使用它。

import accounts from '../models/account/'
class Transaction {

    static debitAccount(req, res) {


        let m = moment();
        const created_on = m.format('dddd, MMMM Do YYYY, h:mm a');

        const {
            amount,
            old_balance,
            transaction_type,
            cashier
        } = req.body;

        let x, y, sum;
        x = amount
        y = old_balance;
        sum = parseFloat(x) + parseFloat(y);


        accounts.forEach((account) => {
           const  account_id = account.account_number;
        });


        const newDebit = {
            created_on: created_on,
            transaction_id: transactions.length + 1,
            account_number: account_id,
            cashier: parseInt(cashier),
            transaction_type: transaction_type,
            old_balance: parseFloat(old_balance),
            amount: parseFloat(amount),
            new_balance: sum
        }

        console.log('New Debit', newDebit);
        transactions.push(newDebit);
        res.status(201).send({
            status: 201,
            message: 'Amount successfully debited!',
            data: newDebit
        })
    }

class User
{
    private $firstname;
    private $lastname;
    private $username;
    private $password;

    public function __construct($firstname, $lastname, $username, $password)
    {
        $this->firstname = $firstname;
        $this->lastname = $lastname;
        $this->username = $username;
        $this->password = $password;

    }


    public static function getUsers()
    {
       require_once 'CSV.php';
       $csv=new CSV('r',USERS);
       $CSVusers= $csv->getAll();
       $users=array();
       foreach ($CSVusers as $CSVuser){
           $users[]=new User($CSVuser[0],$CSVuser[1],$CSVuser[2],$CSVuser[3],$CSVuser[4],$CSVuser[5],$CSVuser[6]);
       }
       return $users;
    }

    public static function getUserByUsername($username )
    {


       require_once 'CSV.php';
       $csv=new CSV('r',USERS);
       $CSVusers= $csv->getAll();
       $users=array();
       foreach ($CSVusers as $CSVuser){
       $users[]=new User($CSVuser[0],$CSVuser[1],$CSVuser[2],$CSVuser[3]);
       }
        foreach ($users as $user){
            if($user->getUsername()==$username){
                return $user;
            }
        }


    }
}

此刻，我从CSV文件获取了一个数组，并将其转换为模型中的对象，但我认为这不是最佳解决方案。