MySQLi连接在另一个类里面

Question

我有这段代码：

<?php
class DBconnection extends Mysqli {
    public $mysql;
    public function __construct($host, $user, $pass, $db) {
        $mysql = parent::__construct($host, $user, $pass, $db);     
    }
}

$mysql = new DBconnection('localhost', '**', '**', '**');
?>

但我不能在另一堂课中建立联系。

<?php
require_once('./mysqli.php');

class Activator {
    private $key;
    public $status;

    public function __construct($key) {
        $this->key = $key;
        $this->status = array();

        $this->activate();
    }

    private function activate() {
        $query = $mysql->query("SELECT email, COUNT(email) AS founds FROM activation WHERE activationKey = '".$mysql->real_escape_string($this->key)."' LIMIT 1");

        if($query) {
            $query = $query->fetch_assoc();

            if($query['founds'] == 0) {
                $this->status['error'] = 'Deze code is verlopen of ongeldig.';
            } else {
                if($mysql->query("UPDATE users SET activation = '1' WHERE email = '".$mysql->real_escape_string($query['email'])."'")) {
                    $this->status['res'] = 'Uw account is geactiveerd!';
                } else {
                    $this->status['error'] = 'Oeps, een fout! Neem contact op per email als dit over 5 minuten nog steeds zo is. Exuses voor het ongemak.';
                }
            }
        } else {
            $this->status['error'] = 'Oeps, een fout! Neem contact op per email als dit over 5 minuten nog steeds zo is. Exuses voor het ongemak.';
        }
    }
}
?>

我怎样才能让它发挥作用？

这是错误：

  

致命错误：无法在第6行的/home/raoul/domains/internetfaq.nl/public_html/dev/mysqli.php中重新声明类DBconnection

Answer 1

您需要在课程中提供$mysqli。由于范围不适用。这可以通过将其作为参数传递给activate()方法来克服：

private function activate($mysqli) {

并致电：

$activator->activate($mysqli);

你不应该多次宣布这个课程。将该类定义放在自己的文件中，然后将该文件包含在需要它的每个页面上。

<强> DBconnection.php

<?php
class DBconnection extends Mysqli {
public $mysql;
public function __construct($host, $user, $pass, $db) {
    $mysql = parent::__construct($host, $user, $pass, $db);     
}
}

<强> file1.php

<?php
require_once('DBconnection.php');
$mysql = new DBconnection('localhost', '**', '**', '**');
 ?>

<强> file2.php

<?php
require_once('DBconnection.php');
$mysql = new DBconnection('localhost', '**', '**', '**');
 ?>

有更好的方法可以做到这一点，但这会让你开始更好地组织代码。