致命错误：无法在第3行的C：\\ xampp \\ htdocs \\ includes \\ classes \\ class.login.php中重新声明类登录名

Question

I'm working on a login. As the base I took PHP-Login because it provides a lot of stuff at forehand. Now I'm getting this error:

Fatal error: Cannot redeclare class Login in C:\xampp\htdocs\includes\classes\class.login.php on line 3

When looking at the first few lines of class.login.php I don't see any mistakes:

<?php
class Login {
    private $db_connection = null;
    public $errors = array();
    public $messages = array();
    public function __construct() {
        if (isset($_GET["logout"])) {
            $this->doLogout();
        }
        elseif (isset($_POST["login"])) {
            $this->dologinWithPostData();
        }
    }

If anyone sees the error, please tell me.

Answer 1

The error message indicates that a class of that name is already declared when this part of the code is reached. This can have multiple reasons:

1. You included php code that declares a class of the same name

2. You included the file "class.login.php" twice using include() or require() instead of include_once() or require_once(). *_once() functions will make sure that contained code is only considered once (as the name suggests) to avoid such errors.

3. You are using a class loader and screwed it up. If this was the case my strong advice is to go without dynamic class loading. It is difficult to read and understand and adds "magic" to the behaviour of your code which in most cases is only clear to one person in the world - to you. Code should be easy to read and understand though.

I hope this helps.