php - 另一个类中的 MySQLi 连接

Question

这个问题在这里已经有了答案:





PHP Fatal error: Cannot redeclare class

(19 个回答)


7年前关闭。




我有这个代码:

<?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', '**', '**', '**');
?>

但我无法在其他类(class)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.';
        }
    }
}
?>

我怎样才能让它工作？

这是错误:

Fatal error: Cannot redeclare class DBconnection in /home/raoul/domains/internetfaq.nl/public_html/dev/mysqli.php on line 6

Answer 1

您需要制作 $mysqli在类内可用。由于范围，它不可用。这可以通过将其传递给 activate() 来克服。方法作为参数:

private function activate($mysqli) {

并称:

$activator->activate($mysqli);

您不应该多次声明该类。将该类定义放在它自己的文件中，然后将该文件包含在需要它的每个页面上。

DBconnection.php

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

文件1.php

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

文件2.php

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

有更好的方法可以做到这一点，但这会让您走上更好组织代码的道路。